IkAWSecond symposiumon the geologyof LibyaUniversity of Al-Fateh -Faculty of Science 'Geology Department

September 16-21, 1978Tripoli 3 iSocialist People s Libyan Arab 0am

Second symposiumon the geologyof Libya5 8 y

University of Al-FatehFaculty of ScienceGeology Department

September 16-21, 1978TripoliSocialist People's Libyan Arab Jamahiriya

TABLE OF CONTENTS

3 Welcome

4 Symposium Committe

5 Symposia on the geology of Libya

7 The University of Al-Fateh

11 Abstracts

67 Biographies

WELCOME TO THEUNIVERSITY OF AL-FATEHTRIPOLI

The University of Al-Fateh welcomes you to theSecond Symposium on the Geology of Libya. Withsuch an international gathering, it is our hope thatyou will enjoy your stay here in the Jamahiriya bothtechnically and socially. The Geology Department,having the honour of organizing this meeting, willendeavour to make it memorable for all.

Dr. Khairi SgaierPresident of the Higher Popular Committee

University of Al-Fatehand Chairman of the Symposium

SYMPOSIUM COMMITTEE

Dr. K. Sgaier ChairmanDr. M. H. Naggar General Secretary

Members of the Committee(Staff members of the Geology Department)

Dr. Z. Abdel KaderDr. F. Al-SawafDr. A. AshourDr. R. BakbakDr. M. T. Busrewil Chairman of the Department

Dr. B. A. EliagoubiDr. A. N. FatmiDr. S. M. GhellaliDr. M. A. GhumaDr. R. KebeasyDr. A. MissallatiDr. M. J. SalemDr. S. L. SarkarDr. A. M. Sbeta

SYMPOSIA ON THE GEOLOGY OF LIBYA

In 1969, the Department of Geology, Faculty of Science, Al-FatehUniversity (then the University of Libya) organized the first internationalsymposium on the geology of Libya. This first symposium was under theChairmanship of Dr. Khairi Sgaier who was then the Dean of the Faculty ofScience. The organizing committee included all members of the staff in theGeology Department and the committee was chaired by Dr. Carlyle Graywho was also the Chairman of the Department at the time.

The response to this first symposium was gratifying. Thirty three paperswere presented at the meetings, 29 of which were subsequently published ina book entitled "The Geology of Libya". This book received a wide nationaland international distribution.

Since 1969, a vast amount of new data has accumulated, adding to andenabling revision of the existing knowledge on the geology of the country.At the same time, there has been a rapid advance is geologic concepts andmethodology. As such, it was therefore decided to hold this secondinternational symposium to provide an opportunity for the discussion andpublication of the new data.

The response to this second symposium was even more gratifying. Over300 geologists from different universities and geological institutionsrepresenting 23 countries will be attending the Symposium. About 110 ofthese will present papers at the meetings of the symposium.

We are very grateful to the University of Al-Fateh for sponsoring thisSymposium. Without such help from the University, its various departmentsand personnel, the Symposium would never have materialized. We are alsograteful for the help offered by the following:- The Geology Department, Faculty of Science, Garyounis University,

Benghazi for co-organizing and co-leading the Jabal Al Akhdar excursion.

The Arabian Gulf Exploration Co. for their part in the organization andhelp in the Jabal Al Akhdar excursion.The Industrial Research Centre for their help and for supplying maps andother publications.The Earth Science Society of Libya.The Secretariat of Foreign Affairs for their help in facilitating visaprocedures.The Secretariat of Internal Affairs for their help in customs andimmigration procedures.The Secretariat of Information for providing information on touristfacilities.The Secretary of Dams and Water Resources for co-leading the Jabal AlAkhdar excursion.The Oasis Oil Co.The Arab Development Centre for printing the field guide book of theJabal Nefusa and Ghadames areas.The National Oil Corporation for their help in organizing the Jabal Gargafand Wadi Al-Shatti field excursion.

The Geology Dept.Faculty of Science

University of Al-Fateh

THE UNIVERSITY OF AL-FATEH

Historical Background

The first university in Libya was established in 1955. It was called "TheUniversity of Libya" and started with the Faculty of Arts. Other facultieswere later established in the three towns of Tripoli, Benghazi and Al Baida(East of Benghazi).- In 1957, the Faculty of Science was established in Tripoli (this faculty later

formed the nucleus of the University of Al Fateh). In the same year theFaculty of Economics and Commerce was established in Benghazi.

- In 1962, the Faculty of Law was established in Benghazi.- In 1966, the Faculty of Agriculture was established in Tripoli.- I n 1967, the two Colleges of Higher Technology and Higher Education

which were previously established in Tripoli with the help of UNESCO,were amalgamated with the University of Libya as the Faculty ofEngineering and Faculty of Education.

- The year 1969 was a corner stone in the evolution and development of theUniversity.With the First ('Al-Fateh' in Arabic) of the September Revolution andemphasis on education and social development, a closer look at theUniversity and its role in the new society was needed. As a result, thedifferent facilities expanded and the curricula were examined and revisedaccordingly. The emphasis was on the University as a scientific and culturalcentre reacting with society and not detached from it, geared to the realneeds of the country rather than staying aloof within the confines of itswalls, producing a new and competent graduate who believes in hisheritage and culture. With this social awareness in mind, new facultieswere planned to fulfill the needs of the country.

- In 1970, the Faculty of Medicine was established in Benghazi. In the sameyear, the existing colleges of Islamic Studies at Al Baida were grouped intoone faculty — Faculty of Arabic Language and Islamic Studies.

- In 1972, the Faculty of Mining and Petroleum Engineering was establishedin Tripoli.

- By 1973, the University of Libya included ten faculties. However, duringthe four years following the Al-Fateh Revolution, social and industrialdevelopments were rapidly achieved with concomitant increase in thenumbers of those seeking higher education. To cope with this newsituation, the University of Libya was split into two independentUniversities in August 1973. viz. the University of Tripoli to include all thefaculties in Tripoli and the University of Benghazi (presently re-namedGaryounis) to include all the faculties in Benghazi and Al Baida. Newfaculties were added to the University of Tripoli e.g. Faculty of Medicine(1973), Faculty of Pharmacy (197S), Faculty of Veterenary Science(1976), Faculty of Education in Sebha (1976), Faculty of NuclearEngineering (1978), thus making a total of ten new faculties.

- I n April 1976 and following the cultural revolution in the University, theUniversity of Tripoli was renamed the University of Al-Fateh.

Facts and Figures about the University of Al-Fateh:Administration:

The University is run by the Higher Popular Committee and theChairman of the Higher Popular Committee (who is equivalent to thePresident or the Chancellor of other Universities).The Higher Popular Committee consists of:- the Chairman of the Higher Popular Committee- the two Vice Chairmen- the Chairmen of the Popular Committees of the various faculties- the General Secretary of the University- A member of staff from each faculty (by election among students)- the President of the Students' Union- A student from each faculty (by election among students)- An elected member of the University non-academic employees and

workers.

Degrees Awarded

The following degrees are awarded by the University- Bachelor Degree (All Faculties)- Diploma (Engineering, Science. Education)- Master (Engineering, Science. Agriculture and Humanities)

Language of Teaching:

Arabic for all Humanities, and mostly English for all other subjects.Feasibility studies are being carried out to evaluate the use of Arabic for theApplied Sciences.

Admission of students and the Yearly Academic System:

Full-time students are accepted on the basis of their marks in G.C.E.examination and the number of available places in each faculty. Sinceeducation is free, this method of selection provides an equal opportunity foreach student.

Faculties of Science, Agriculture, Pharmacy and Medicine follow atwo-term system with an examination period at the end of each term(February and June). Faculties of Education, Engineering, Mining andPetroleum Engineering and Veterenary Science follow a full year systemwith one examination period at the end of the Academic Year (June).

Budget:

Since the division of the University of Libya in 1974, the budget of theUniversity of Al-Fateh alone is as follows:Year Current Expenditure Development

(millions L.D.) (millions L.D.)1974 6.6 10.1197.-5 7.5 36.61976 9.6 29.91977 11.0 29.01978 14.5 30.0

Library

The University Central Library houses approximately 19,500 books inArabic and 10,400 books in English. It also subscribes to approximately 400international journals.

Staffing

Non-academic Staff: A total of 935 out of which 117 are non-Libyan of10 different nationalities.

Academic Staff: A total of 762 staff members out of which 410 arenon-Libyan of 12 different nationalities. This is apart from the distinguishedVisiting Professors who are frequently invited on a short term basis.

Students

(A) Post graduates: A total of 724 distributed as follows: 533 studyingabroad for M. Sc. and/or Ph. D. degree and 119 demonstrators studyingat the Al Fateh University.

(B) Undergraduate Students: A total of 5488 students (4152 males, 1336females) compared to a total of 1374 students (1213 males, 161females) in 1969/1970.

Data on the Faculty of Science

Departments: Mathematics, Physics, Chemistry, Zoology, Botany,Statistics, Geology and Computer Science.

Members of Staff: 251 members (154 non-Libyans)Students: 763 students (Libyans: 454 males, 161 females -

Non-Libyans: 90 males, 58 females).The Faculty of Science is also responsible for teaching the science subjectsrelevant to various other faculties in the University.

The Geology Department

The Geology Department started in 1960 with Dr. Chapman as theChairman and only staff member. The number of the students then was 13.Presently, the Department comprises 15 Staff members, 5 demonstratorsand research assistants and 80 students (excluding the first year students).

The present Chairman is Dr. M. Busrewil.Since its establishment, about 285 geology students graduated and took

employment in different secretariats and institutions (e.g.) 30% inSecretariat of Petroleum, 16% in the Secretariat of Dams and WaterResources, 15% in the University of Al-Fateh, 8% in the Secretariat ofIndustry.

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ABSTRACTS

Second symposiumon the geologyof Libya

University of Al-FatehFaculty of ScienceGeology Department

September 16-21, 1978TripoliSocialist People's Libyan Arab Jamahiriya

The Abstracts have not been edited by the SymposiumCommittee and are presented here in the form in which theywere received from the authors.

I I

Geophysical Analyses of Gravity data inthe Northern Borderland Between Egyptand Libya

Y. E. Abdelhady

Recent work by Agarwal and Lai (1972),Mufti (1972) and others made availablesome information concerning subsurfaceshallow and deep seated structures fromgravity analyses. Second vertical derivative,residual, regional and downwardcontinuation maps were constructed onmathematical basis for the area underinvestigation. The computation operationswere carried out using I.B.M. 1620Computer. All maps were constructed usingdifferent grid spacing and various cocfficicnsjust to select the maps which bring up betterunderstanding of the subsurface structuralpattern of the area under study.

Geldart et al (1966) method was followedto evaluate faults parameters within the areaunder study along representitivc profiles.

After making comparative study betweenthe oldest methods of gravity analyses suchas Griffin (1949), Rosenbach (19S3 a),Constantincscu (1961) and the up to datemethods as Agarwal and Lai (1972) andMufti (1972), the author found that the up todate methods are more reliable and havehigh resolution power in sedimentary basinshaving the same conditions as the area underinvestigation.

From this study the author constructed amap of the major tectenic trends in the areawhich is of importance as potential sector foroil exploration.

Mineralogical Properties of the ClayFraction of Sarir Shara Soils andSediments

Gilani Abdelgawad, Ezzedein Rahoma andW. Busch

A study of the clay fraction of major soilseries and sediments in the Sarir area,southeast of Libya, disclosed a number of (a)morphological features reflecting a minimumof pedogenic processes (aeolian as well asalluviation activities), and (b) mineralogicalstructures exhibiting domination of the clayfraction by expansible 2: 1 - layer silicates.

Fibrous clays of the attapulgite(palygorskite) form appear to be present inthese soils, but the evidence obtained is to beconfirmed.

Water Resources of South-easternLibyan Sahara

Moid U. Ahmad

The Kufra and Sarir basins have huge groundwater resources. Kufra basin alone containsabout 25,000 Km3 of good quality water.

In the middle of the Sahara desert, a waterwell field (KPP) consisting of 102 wells wasconstructed by the end of 1972. Each well is300 meters deep, designed to produce 76L/S, and fitted with a self-propelled sprinklerwhich rotates over 100 ha in 60 hours. Thedistance between-each well is 1120 meters.By using fertilizers and continuous irrigationover the coarse sand, a very high yield ofalfalfa has been obtained.

In 1974-7.5, another well field consisting of35 wells, Kufra Settlement Project (KSP)was constructed adjacent to KPP. At therecommendation of Ahmad, the wells weredrilled up to a depth of 475 meters. Thespecific capacity of these wells doubled andtripled those of KPP wells.

Analytical and digital models indicatethat the aquifer is behaving as leakyaquifer and most of the water isobtained from the shallow aquifer. The effectof partial penetration is greater than hasbeen p rev ious ly a c k n o w l e d g e d .Transmissivitles appear to be increasingas the cone of depression affects greaterdepths of saturated thickness. Thetransmissivity may be of the order 3700M2/D in contrast to 1000 M2/D determinedby pump tests.

In 1974, Ahmad designed the South Sarirwell field consisting of 159 wells about 400km north of Kufra well field. Thirty wells intwo rows, 2'/2 kms apart, are about 300meters deep and screened from 150 to 300meters. Six lines of 30 wells are spaced 10kms apart perpendicular to the piezometricgradient. Long term pumping levels werepredicted using Hantush leaky equation. 40to 55 wells were pumped till April 1977. Thedrawdown data indicated an apparentstorage coefficient of 02 after 600 days ofpumping.

Ahmad designed the North Sarir WellField which is situated near 28° N. latitudeand 22° E. longitude, about 30 kms west ofSarir Oil Field. 80 wells have been drilledsince 1977. The wells, 300 meters deep andscreen ed between- 150 and 300 meters, aredesigned to pump 76 L/S.

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Wells of exceptionally high capacity(30-60 MVHrM and transmissivity rangingfrom 3600 to 9800 M2/D) are found in sandygravel which arc overlain by thick beds ofplastic shale containing lamillibranchiata.The shale beds disappear to the east andwest in the adjacent wells but persist in anorth-south direction. The variable contentof feldspars & three types of quartz grainindicate that the source is an ancient terrane,perhaps the Pre-Cambrian rocks of theTibesti Range. The hydrological studyindicates the existence of an ancient riverchannel which has been named Sarir channel.

The existence of this and otherundiscovered channels near Kufra, Sarir,Ta^erbo and Jalo well fields may alter thepresent mining concept because thesechannels may be recharged from rains inTibesti and Sudan.

A study of Landsat data since 1972.indicated that the cloud coverconcentrateshto the northwest and northeastof Tibesti Mountains between 23° N. and20° N. latitude. The color composites ofLansat 1 on 2-5, 26 Sept. and 30 Oct., 1972show the presence of near surface groundwater in several streams coming from themountain and then infiltrates into the sands.

Salama has determined the magnitude ofrecharge in the Sudanese Sahara Nubianbasin which is in the southeast of Kufrabasin. The amount of water recharged isestimated to be 20.6 million cubic meters peryear, the abstraction rates are 1.2 millioncubic meters per year and the amount ofwater permanent storage is 9740 millioncubic meters.

A new well field to irrigate 10,000 has isbeing planned at Tazerbo and a well fieldconsisting of 33 wells is under construction atJalo.

On the basis of the behavior of Sarir andKufra well fields, it would be possible toconstruct several more highly productive wellfields in the Kufra and Sarir basins.

Palynology and biostratigraphy of theTanezzuft and Acacus formations fromthe Ghadames basin, Tripolitania, Libya

T. K. Al-Ameri and J. B. Richardson

Palynological studies on more than iOOsamples from 13 boreholes of marinedeposits of upper Ordovician and Silurian(Llandovery, Wenlock, Ludlovian and

"Downtonian") and possibly LowerDevonian age from the Ghadames basin inTripolitania — Libia have revealedacritarchs, tasmanites, miosporcs, chitinozoa,scolecodonts, plant tissues, eurypterid cuticleand graptolite siculae. 18 palynological zonesbased on miospores, acritarchs, andchitinozoa from the upper Ordovician topossibly Lower Devonian have beenestablished. Six distinct types of palynofaciesare fitted into a hypothetical model relatedto distance from shore line and it istentatively suggested that they may relate tolagoonal, intermediate and open marineenvironments.

Lower Tertiary Stratigraphy andTectonics of Northeastern Libya

/•'. T. Ban

The importance of early Senoniantectonics has been demonstrated in the coreof Jabal al Akhdar. However, it appears thatorogenic movements culminating in the EarlyTertiary (late Landenian) may be responsiblefor some of the most widespreaddeformation recognized over much ofnorthern Cyrenaica.

Paleocenc outcrops in Jabal al Akhdar arerare; however, the presence of Paleocenefossils in distant parts of this region suggeststhat outer neritic seas covered the northernjabal perhaps even depositing a uniformchalk sequence, similar to the Al UwayliahFormation, over much of this area. Thescarcity of Paleocene sediments is the resultof erosion following a major orogeny whichfolded and uplifted the entire Jabal alAkhdar. This strong tectonic event, herereferred to as the Cyrenaican Orogeny,probably produced its first labor pains duringthe Late Creataccous (possibly Campanian),and reached its maximum intensity in theEarly Tertiary bringing the Paleocenc to aconclusion. The result being that most if notthe entire region was subjected to severesubaerial erosion at the end of Paleocenetime. Final movements, albeit weak, mayhave persisted into the Early Eocene. Theorogeny has not been recognized in the SirtcBasin where, in its deeper parts,sedimentation appears to be continuousthroughout the Maestrichtian, Paleocene andEarly Eocene.

Following the Cyrenaican Orogeny, aLower Eocene (Ypresian) transgression

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commenced, with seas slowly onlapping thesteep flanks of the folded-uplifted highlands.This transgression continued its advance intothe Middle Eocene (Lutetian) when most ofnorthern Cyrenaica was again innundated bywarm neritic Tethyan water. Thistransgression is evidenced by the depositionof the Apollonia Limestone. Stratigraphicsections have been measured along the coastbetween Derna and Susa which demonstratethis transgression. In the area of Marsa alHilal, one of the few areas where the UpperCretaceous Atrun Limestone — EoceneApollonia Limestone unconformable contactis exposed, considwrable evidence isavailable indicating the duration of thistransgression. In Wadi al Atrun, a LowerEocene (Ypresian) section of bathyalApollonia Limestone unconformably overlieslower Maestrichtian Atrun Limestone. Ninekms to the west, in Wadi al Qalah, MiddleEocene (Lutetian) Apollonia Limestoneunconformably overlies the AtrunLimestone. These sections indicate thatduring the Ypresian, on the flanks of a majorCyrenaican orogenic fold, bathyal conditionsoccurred, while only a few miles to the west,the structural axis was emergent. This wasfollowed by Lutetian Limestones of the sameformation, representing outer neriticdeposition, which covered the entire area.These observations are in part corroboratedby subsurface information.

Mineralogical composition of JabalNofusa phonolitesW. M. Bausch

The Jabal Nefusa phonolites arecharacterised by dominance of felsiccomponents, or a very low color ratio. Asmentioned by Almond et al. (1974), theremay occur phenocrysts (mostly of alcalifelspar), but generally the phonolites are finegrained, poorly crystallised or even aphyric.

Besides microscopical analysis, themineralogical composition has to beinvestigated essentially by means of X-raydiffraction. As main (felsic) componentswere found: sanidine, analcite, nepheline,sodalite and albite (given in order ofapproximately decreasing frequency).

The frequency of analcite is astonishing,and was not described before. There aregiven the relations of changing proportionsof mineralogical compositions and detailedX-ray data.

Gravity Anomalies in Coordination withFault Parameters and Geotectonic setup in the Northern Western Desert ofEgypt

A. I. Bayoumi and M. B. Awad

The critical analysis of the observedgravity anomalies in the central portion ofthe Northern Western Desert of Egypt,particularly along an E-W trending profilestretching over S00 kms. across the desertand including the Qattara Depression revealsthat the area is generally characterized byseveral structural features in the form ofnormal faulting of different ages and depthextents, with a maximum throw of 3000meters.

Trucations and wedging ups of particularinterest seem to be also complicating therelatively thick sedimentay section overlyingthe basement complex which lies inthis particular area at depths greater thanS kms.

Fault parameters including the densitycontrasts between the faulted "slabs" and thecountry rocks either sedimentary orcrystalline, have been also evaluated, using asimple, rapid and consistent technique,illustrated mainly in the form of a new set ofnomographs that have been theoreticallycomputed by making use of fault slabformulae.

To narrow the wide range of possiblesolutions arising from ambiguities in gravityinterpretations, seismic reflection control hasbeen taken into consideration.

The present study, which also includesstatistical analysis of gravity anomalies;namely, in the form of residuals, indicatesthat the geotectonic lateral compressionalfroces acting on the Northern portion of theAfrican Shield seem to develop three majorsets of Stress/Strain trend patterns ofdifferent tectonic phases. The oldest one,which runs almost along a N 3">°W, seems tohave been rotated anticlockwise (westwards)through a maximum angle of about 30°,initiating, the second phase of tectonismwhich is responsible for developing thesecond Stress/Strain trend pattern. Thisanticlockwise rotation in the originaldirection of the geotectonic forces isprobably due to the anticlockwise rotation ofAfrica relative to Arabia.

As a result of the clockwise rotation of

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Africa relative of Arabia the direction of thegeotectonic forces changed again eastwardsfrom its old direction to reach a new positionhaving a N 5°W direction.

Accordingly, it is stated here that:1) The Gulf of Suez is not a conjugate

shear of the Gulf of Aqaba as has beenalways assumed by many authors.

2) The theree phases of deformations wereactually responsible for the development ofthe Gulf of Suez, Gulf of Aqaba, and theMediterranean trends, rcspectivly.

Implications of geotectonic setting of ELHamada El Hamra, Western Libya inview of potential field data

A. Bayoumi and A. Missalati

The present study is mainly concernedwith the analysis of the anomalous featurescomplicating the normal distribution of theearth's gravitational field in an area lyingwithin EL Hamada EL Hamra Basin,Western Libya between Latitudes 28°30' N -30°()0' N and longitudes l()°00' E - 13c00'E.

The study emphasizes that such an area —being bounded from the south by the GargafUplift and from the north by the southernflank of the Ghadamis Trough — ischaracterized by several local structuralfeatures, mainly in the form of horsts,grabens, and step faulting. Such structuralfeatures, which seem to have been originallyinitiated and developed by crustalmovements at depth, are of differentintensities, and trend patterns.

The present work also indicates thatseveral of the observed anomalies signifyeither local structures complicating thebasement complex or being associated withlithologic variations within the basementitself from metasediments and metavolcanicsto granites.

On the other hand, the statistical analysis,which has been carried out on the "keyvariables" of the different local gravityanomalies, particularly those which havebeen analytically continued downwards tofive different levels below the Bouguer one,readily reveals the following;

1) The area seems to have been subject toseveral tectonic cycles during the differenttectonic phases which prevailed the areathrough its geologic history. Such tectoniccycles are considered to be generally

responsible for the developement of majordeformation trends corresponding faily wellwith those of the Gulf of Suez, Gulf Aqaba,Mediterranean and with intensitiesexponentially decreasing with increasingdepth as well as the formation of a numberof stratigraphic and structural traps ofeconomic interest.

2) The depth to the top of the basementcomplex, which corresponds to the levelalong which maximum variations in thetectonic parameters occur ranges between afew hundred feet in the southern portion ofthe area to more than 4 kms, in the north,with an average of about 2.5 kms.

3) The level along which the strainvanishes lies at about 10 kms, whereas thelevel along which the applied geotectonicforces reaches a minimum occurs at about 30kms, which is more or less comparable tothat of the lower limit of the base of the crustin Northern Africa.

Ground Water Nitrate Pollution in theQuaternary Aquifer, Eastern and CentralGefara Plain, S.P.L.A.J.

Dr. Mohamed N. Belaid

Concentrations of nitrate in the groundwater of the Quaternary aquifer of theGefara Plain are relatively high. Water from6.94 percent of the sampled wells had nitrateconcentrations less than 10 ppm, 93.06percent had greater than 10 ppm and 48.55percent had greater than 45 ppm. Groundwater with nitrate concentrations exceeding45 ppm can cause nitrate poisoning(oyanesis) to infants. Progressive increase ofnitrate concentrations has occured in somewells. Concentrations decrease withincreasing well depth and well penetrationbelow the water table. Quanternary deposits,composed mainly of sand and gravel containabnormal nitrate concentrations. Potentialsources of nitrate are fertilizers, feed lots,several types of legumes and the evaporitedeposits in the south-western part of thestudy area.

Stratigraphic contributionto the Paleozoic of SouthernBasins of Libya

E. Bellini - D. Massa

Part I - General Framework of the Murzukand Ghadames Basins (D. Massa).

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The geology of the southern basins ofLibya is particularly important in the generalcontext of Africa. In our work the Paleozoicof these basins will be studied, from theCambrian to Upper Carboniferous. The mostrecent publications concerning Libya and itsneighbouring countries will be taken intoaccount.

The Murzuk and Kufra basins represent infact the two easternmost intracratonic basinsof North Africa. They are sedimentary basinsof prevailingly marine fades, affected byrecurrent continental influences morefrequent in the Kufra basin.

The paleogeographic and faciologicevolution of these basins are directlyconnected with Caledonian and Hercynianorogenic events which are clearly recordedand dated.

The knowledge about the geology ofsouthern Libya has evolved in a progressiveway. From 1930 to 1940, reconaissance tripsand first systematic observations were mademainly by italian geologists under thedirection of A. Desio.

From 1944 to 1955, due to the efforts offrench geologists, mainly M. Lelubrc andJ.M. Freulon, the geological knowledge ofLibya advanced considerably, especially inthe western part.

Since 1956, a very important work hasbeen realized by petroleum geologists(Fezzan and Ghadames basin); a greatnumber of boreholes have been drilled inLibya, mostly in the Sirte and Ghadamesbasins.

From 1961 to 1976, AGIP improved thestratigraphic data about the Paleozoicoutcrops of the Kufra basin and thesubsurface Paleozoic sequences ofcentral-eastern Cyrenaica.

Finally, the efforts of the Libyan geologistslargely contributed to the knowledge of thegeologic framework of this huge country.Some of their views have been published.

Now, 20 years after the beginning ofpetroleum exploration, a synthesis might beattempted. The work, however, is still inprogress and certainly will further specify thecontents of the present study. Unfortunately,a detailed geological map of these two basinsdoes not yet exist.

Part II - The Murzuk Basin (D. Massa).This huge intracratonic basin is situated

East of the Hoggar Massif and West of the

Tibesti. It presents a complete Paleozoicseries, from Cambrian to Carboniferous, ofwhich the geological age has been establishedby means of correlations with the wellstudied Ghadames basin.

Sediments of the Infracambrian/Cambriancycle are overlain by a reduced thickness ofLower and Middle Ordovician. The greatglacio-marine episode of Upper Ordovicianage, known all over North Africa, exists inLibya, where it has been dated Caradocianand Ashgillian. The wide Siluriantransgression throughout North Africa, hasreached the Murzuk basin during theLlandoverian.

After the long Middle and Upper Silurianemersion, the region was submitted to theeffects of the Caledonian orogenesis. Thepost-Caledonian sedimentary mega-cyclc isof Early Devonian age (Tadrart and OuanKasa Fms: Pragian and Emsian). The Middleand Upper Devonian (Aouinet Ouenine Fm)with marine influences is related with theDevonian of Europe (Couvinian, Givetian,Frasnian and Famennian).

The Devonian mega-cycle ended withregressive sequences (Tahara Fm) ofStrunian age.

The marine Carboniferous was the lastepisode of the Paleozoic. The transgressionhas been dated Upper Tournaisian: theCarboniferous sediments show mixed marineand lagoonal facies.

Locally sediments of Visean, Namurian,Bashkirian and Moscovian age have beenidentified.

During the Upper Carboniferous, redcontinental sediments were deposited(Tiguentourine Fm).

The Hercynian orogenic phase is apparentthrough the folding of the Paleozoic seriesand through magmatism phenomena.

Part 111 - The Kufra Basin (E. Bellini).The Kufra basin lies South-East of the

Sirte basin, between the Tibesti Massif to theWest and the high plutonic ring complexes ofJebels Archenu and Uweinat to the East.

The stratigraphic data available about thisbasin are mostly due to geological andphotogeological surveys. Petroleumexploration is just beginning and no deepwell has been drilled so far.

Stratigraphic boundaries in the geologicalmaps arc mainly based on mapped lithostratigraphic units but most of them lack

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of sound biostratigraphic evidence and fossilsrecords which might allow a confident anddetailed dating of the sediments.

In their broad lines the Kufra and theMurzuk basins show a parallel geologic-evolution. A wholly clastic sedimentarysequence is present in the Paleozoic (andPost-Paleozoic) of the subject basin.

The metamorphic Pre-Cambrian Basementis overlain by a very thick sequence ofCambrian and Ordovician age; locally anerosional surface, formed at the time of thegreat north african ice sheet, separatesCambrian (Hassaouna Fm) and UpperOrdovician sediments (Memouniat Fm).

In the Kufra basin, the Silurian marineingression reached the south-eastern areaand, probably, the northern area during theUppermost Ordovician (Ashgillian). Lowerto middle Silurian sediments consitute acomplete sedimentary cycle; a very shallowmarine environment is dominant (AcacusFm).

Again the post-Caledonian sequencerepresents a sedimentary cycle of dominantlycontinental environment at the base (Tadrart- Ouan Kasa Fms) passing to open shallowmarine during Middle-Upper Devonian(Binem Fm) and, locally, to marinc-lagoonalin the uppermost part.

The Carboniferous sequence is mostly ofcontinental environment and withpronounced thickness (Dalma Fm); a shortmarine episode, of probable Visean age, hasbeen found both in the south-western andnorth-eastern outcrops of the basin.

Hercynian orogenic events caused theuplifting of the basin during Carboniferoustimes; as far as we know the presence ofUpper Paleozoic or Lower Mesozoic(continental) sediments in the most sinkingareas of the basin, is only hypothetical.

Post-Eocene Sedimentation in theEastern Sirte Basin, Libya

A. C. Ben field and E. P. Wright

Reinterpretation and synthesis of oilcompany well logs supplemented by sampleand geophysical log data fromhydrogeological exploration boreholes hasprovided new information on thePost-Eocene succession in a 76,000 squarekilometre area of Central Cyrenaica situatedin the east of the Sirte Basin. In the southwest of this area Oligocene sediments,

commonly between 700 ft and 1000 ft thick,comprise glauconitic sands and sandstoneswith interbedded shales, deposited intransitional and marine environments,overlain by fine to coarse sands withoccasional clays, of fluvio-contincntal origin.Northwards the fluvial sands thin out withina dominantly marine sequence of shales,sands and carbonates which exceed 2300 feetin thickness in a northerly plunging troughmidway between Jebel and Amal oil fields.

The full thickness of the succeding Lowerand Hiddle Miocene Marada Formationreaches over 3000 ft in the same trough, butelsewhere is around 1200 ft. Fine to coarsesands dominate the formation in the westand south shales, evaporites, sandy shalesand sandy carbonates and ultimately die outnorth eastwards within interbedded clays andcarbonates. Facies relationships indicate thatthe shoreline complex recognised at outcropfurther west extends into the sub-surfacewith a south easterly trend.

Over the north eastern half of the area theMarada Formation is overlain with sharpdisconformity by the newly recognisedPost-Middle Miocene Calanscio Formationcomprising up to 600 ft of unfossiliferous,fine to coarse sands, pebbly in part, withimpersistent thin clays, which was depositedunder fluvial conditions.

The Quaternary is chiefly represented bythe aeolian sands of the Calanscio andRebiana Sand Seas, together with thingravels, surface calcretes, residual soils andLacustrine deposits.

The paper concludes with a resume of thePost-Eocene sedimentation in the area inrelation to its regional stratigraphic context.

Foraminiferal Biostratigraphy andPaleoecology of the ApolloniaLimestone (Eocene) of Cyrenaica (NeLibya)

W. A. Berggren

Foraminiferal biostratigraphy and ecologyof the Apollonia Limestone (Eocene) atthree sections in NE Libya (Cyrenaica) isdescribed.

The lower 110' (33.•> m) of the 220' (67m) thick section of Apollonia Limestoneexposed at Wadi al Atrun essentially spansthe Early Eocene (Zones P6-basal P10) andlies unconformably upon the earlyMaestrichtian (Globotruncana tricarinata

17

Zone) Atrun Limestone. At Wadi al Qualah(~ 8-9 km west of Wadi at Atrun) theApollonia Limestone is of Middle Eocene(upper part of Zone Pll) age and liesunconformably upon the late Maestrichtian(Ahathomphalus mayaroensis Zone) AtrunLimestone. The lower 36i' (11 m) of the42")' (130 m) "Pyramid Peak" section ofApollonia Limestone (~ 6 km east of Wadial Atrun) essentially spans the MiddleEocene (upper part of Zone P10-P14). Abasal contact has not been observed in thissection.

Morozovellids (subbotinae, gracilis,aragonensis) and acarininids (soldadoenis,coalingensis, pentacamerata) characterize thelower part of the lower Eocene section atWadi al Atrun. The appearance of Subbutinasenni and Acarinina densa and the relativelycommon occurrence of the Acarininapentacamerata-aspensis group is used todenote the P9-10 interval in the upper part.Reworked Maestrichtian (globotruncanids)and (? reworked) Paleoccne (Morozovellavelascoensis, Planoroialites pseudomenardii,Subbotina velascoensis) elements are presentin the basal sediments immediately above theunconformity. This is the first record ofPaleocene in north central Cyrenaica.

A nearly complete Middle Eoceneplanktonic foraminiferal succession is presentin the Pyramid Peak section. Commonplanktonic elements include Truncorotaloides{rohri, collactea), Globigerapsis (kugleri,barri-mexicana group, subconglobatus),Subbotina senni and the "Turborotalia"pomeroli group.

The single sample examined fromimmediately above the unconformity at Wadial Qalah contains a rich planktonic faunaincluding, i.al., Morozovella (Lehneri,broedermanni), Acarinina densa,Truncorotaloides (rohri and topilensis),Globigerapsis kugleri, "Turborotalia"possagnoensis and Subbotina linaperta whichindicates a position within the upper part ofZone Pll.

The lower Eocene section at Wadi alAtrun exhibits a pronounced shallowing inthe Zone P9-10 interval from (probably)upper bathyal (200-600 m) to mid-neritic (<100 m) depths. The bathyal fauna (ZonesP6-P9) is characterized by Nuttallidestruempyi, Vulvulina spinosa, Alabaminadissonala, Globocassidulina subglobosa and"Planulina" cushmani. This fuana is replaced

rapidly within Zone P9 by one characterizedby hispido-costate (gardnerae-rippensisgroup) uvigerinids, costate (jacksonensis,instabilis, macilenta) buliminids, Cibicidoidcs(alleni, spp.), Operculina and Nummulites.Planktonic foraminifera, common in thelower part of this section, exhibit a markeddiminution towards the upper part, anddisappear in the uppermost part, above thelevel of the appearance of Nummulites. The(local) termination of several bathyal taxa inthe later part of the early Eocene mirrorsthat seen at equivalent horizons in California(Lodo Formation) and coincides closely withrecent interpretations made by seismicstratigraphy of a major eustatic sea-levelchange near the early/middle Eoceneboundary. However, the presence ofcontorted slump masses in the Wadi al Atrunsection within this interval suggests that localtectonism may also have been a factor in thechange in bathymetry seen in this section.

The Middle Eocene "Pyramid Peak"section contains a rich and well preservedbenthonic foraminiferal fauna which remainsessentially uniform throughout and exhibits amarked affinity with the upper Eocene(Jackson) faunas of the Gulf Coastal regionof the United States. The diachroneity inbenthonic foraminiferal assemblages isattributed to the fact that Middle Eocenefacies in the Gulf Coastal region contain astrong terrigenous component, wherascarbonate sequences, similar to that inCyrenaica, are characteristic of the LateEocene (Jacksonian).

Characteris t ic elements includehispido-costate (gardnerae) and striate(dumblei) uvigerinids, costate (jacksonensis)buliminids, Cibicidoides (cocoaensis,pippeni), Anomalinoides bilate ralis,Planulina sp. cf. P. cocoaensis andcompressed and inflated lenticulinids andcostate marginulinids. The appearance ofBaggina sp. and Florilus spissa in theP12-P14 interval suggest moderateshallowing in the younger part of the MiddleEocene. The total absence of nummulitidsand operculinids is noted and, together withthe relatively abundant planktonic fauna andabsence of typically bathyal elements,suggests that deposition occurred on theouter part of a carbonate shelf (outer neritic:~ 100-200 m).

The single sample examined from theWadi al Qualah section (Zone PI 1) contains

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a benthonic fauna essentially identical to thatfound at comparable levels in the PyramidPeak section with the notable addition ofNummulites and Operculina. This suggestsdeposition at somewhat shallower depths(middle neritic: ~ iO-lOO m) than thePyramid Peak section.

Infiltration Conditions of MajorSandstone Aquifer Around Ghat, Libya

David J. Burdon

Ghat and Wadi Tanezzuft are situated onthe outcrop of Cambro-Ordoviciansandstones on the south-western flank of theFezzan Groundwatcr Basin. Thesesandstones are major aquifers extendingbeneath most of the Basin, which has an areaof the o rder of 4->0,000 km 2 .Hydrogeological investigations over the past25 years have generally led to the acceptanceof the Ghat region as one of groundwaterinfiltration and aquifer recharge, so thatgroundwater flow is assumed from the southand south-west to the north and north-east.These concepts are based on limited data atpoints which are far apart, and with atendency to assign to unexamined orinaccessible areas, characteristics which fitthe general accepted concept for the Basin.

Field investigations in the Ghat area earlyin 1977 showed that many of the phenomenaobserved were incompatible with the conceptof the area being one of infiltration andaquifer recharge. It appeared that infiltrationdocs not occur as there are perennial poolson the sandstone in some wadis; that thegroundwater is generally confined even withno definite impermeable cover; that in placesthe sandstones have been cemented toquartzites; that groundwater temperaturesare high, but not abnormally so; and thatgroundwater mineralisation is low.

A working hypothesis is presented whichseems to reconcile these contradictory factsand fit them into a coherent picture of whatmay have occurred following decreased or nilinfiltration after the end of the last fluvial,say 10,000 years ago. Then decreasedgroundwater put-through allowed thegeothermal heat flux to warm up thegroundwater; in turn geothermally inducedconvection flow reversed groundwater flowon the recharge limb and boosted flow on thediscarge limb; this was reinforced byaqua-thermal effects in the sandstones and

the shales. Meanwhile, initial falls ingroundwater levels in the recharge area hadproduced a vadose zone at the base of whichsilica was precipitated, sealed the aquifer andprovided an impermeable carapace with thesandstone when the groundwatcr again roseunder geothermal heat and pressure effects.In this way, confined groundwater is nowfound in what appears to be an opensandstone aquifer. The hydrochemical dataneither favours nor disproves this workinghypothesis, which may be referred to as a"hydrothermal" working hypothesis.

The paper does not present this workinghypothesis as if it were a proven explanationof the hydrostatics and hydrodynamics of amajor groundwater basin. It draws attentionto the danger of accepting one conventionalhypothesis as proven, and emphasises theneed for the multiple hypotheses approachwhen data is scarce and spread over vastareas, some almost totally inaccessible.

On the origin of the Messak Mellet andPlateau du Mangueni escarpment

Dellef Busche

The Messak Mel le t /Pla teau duMangueni-escarpment, which is up to 300 mhigh, separates the Nubian sandstone surface(up to 1.100 m high) of the south andsouthwest margin of the Murzuk basin fromthe foreland surface (600 - 700 m high),which is largely developed in uppercarboniferous limestone.

Strata generally dip towards the center ofthe Murzuk basin at a very low angle, but 'still somewhat steeper than the slope of theplateau surface toward the Murzuk sand sea.Geological profiles taken along theescarpment show that the border betweenthe limestones and the Nubian sandstone, orbetween triassic red clays and the sandstonevaries in altitude as the result of morepronounced uplift in the region south ofAnai and in the Enneri Achelouma region onone side and relative depressions in theSalvador area and north of Anai. E.g. southof Col d'Anai less than the upper third of theescarpment face is in Nubian sandstone, asis the case in the El Oumr area. Theseobservations, together with aerialphotograph interpretation, lead to theconclusion that the upper plateau surface isfully denudational, lowered beneath theinferred structural surface of the Nubian

sandstone by at least 100 to HO m.Morphological features older than the

escarpment are two surfaces linked by gentleslopes, insclbergs of various heights withbevelled tops, steep-sided valleys with rockterraces converging toward the basin center,and numerous endorheic non-structuraldepressions ranging from a few meters toseveral kilometers in diameter. The largevalleys are best preserved north of Salvador,where all of them strike out into the air atthe plateau rim at full width and depth,indicating that they are much truncatedremnants of much longer valleys oncecoming from the west. It is through these oldvalleys that much of the sand seems to havebeen transported into the center of the basinto be transformed into the Murzuk sand sea.The presentday watersheds are much tosmall to have served as principal supplyareas. The sand sea lies on the lowest anddissected erosion surface of the plateau.

In the course of surface lowering inprc-escarpment times the less resistant strataof triassic clays must have appeared at thesurface first in the above-mentioned areas ofgentle uplift. Facilitated erosion in the softclays appears to have resulted in differentiallowering of those surface areas as comparedto those parts of the surface still being insandstone. Thereby was initiated the growthof the escarpment, and the old drainagesystem was gradually dismembered. In thePlateau du Mangueni traces of W-E-trendingpre-escarpment drainage are cut at rightangles by vylleys tributary to the EnneriAchelouma plain.

Lowering of the foreland seems to haveprogressed step-wise, so that the escarpmentgradually grew from a gentle rise to a heightof sometimes more than 300 m. This processcan be traced in numerous slope profiles andsurface remnants preserved on the tops ofinsclbergs along the whole escarpment. Twoperiods of development have to bedistinguished: the more important older oneof step-wise vertical lowering almost down tothe lowermost rock surface, for which gentlesigmoidal slopes between" the upper andrespective lower surfaces were characteristic,and a younger phase of progressivesteepening of the escarpment slopes up tothe point of slope failure along all thosesections it is where clays were present.During the latter phase the lower most rocksurface was not remarkably lowered, but

toward the end of this phase consiferabledissection seems to have set in. Thisoversteepening, which seems to have been areflection of changing climatic conditionstoward more aridity, has led to large-scalelandsliding (cf. abstract and paper byGrunert in this volume).

Parallel to the growth of the escarpmentand the dismembering of the old riversystems a new dendritic runoff patternestablished itself on the (upper) plateausurface, developed best north of Anai. Withthe exception of one area in the south of thestudy region the regional divide closelyfollows the plateau rim, often less than 100m from it. Water-courses whose headreaches have been truncated by slope retreatare virtually absent, even where landslidinghas taken place. This indicates that theescarpment has practically not changed itsposition since the initial stages of itsdevelopment, with the exception of tahtaslope retreat that occured with thelandsliding. The dendritic drainage system inits present form has originated after thelandslide phase.

No evidence could be found for thesupport of the commonly held opinion ofsubparallel slope retreat over manykilometers. The reconstructed model ofdifferential surface lowering is in agreementwith results obtained in the Tibesti andHoggar Mts.

The Basanitic Volcanoes of the Charianarea, N. W. Libya

M. T. Busrewil and W. J. Wadsworth

The most recent phase of Tertiary —Quaternary volcanic activity in the Gharianarea of N. W. Libya gave rise to a series ofsmall volcanic vents and associated minorintrusions, less than 12 m.y. old. These arcmainly of basanitic composition, althoughsmall quantities of undersaturatedtrachybasaltic differentiates have developedlocally. Lherzolite fragments have beenrecorded from a number of localities. Brieffield and pctrographic descriptions arepresented, together with 21 new chemicalanalyses.

A two-stage petrogenetic scheme isproposed. It is suggested that the basaniticmagma was generated by partial meltingof upper mantle lhcrzolites, possiblyaccompanied by eclogitc or olivine opx

20

fractionation. Subsequently, limitedlow-pressure fractionation involving oliviencpx is believed to have occurred insub-volcanic chambers or within the volcanicedifices, to produce small volumes of residualtrachybasaltic material.

The Cainozoic Igneous rocks of Jabal alHaruj al Aswad, Libya

M. T. Busrewil and W. J. Wadsworth

The Haruj volcanics comprise one ofNorth Africa's most voluminous alkalineigneous provinces. The volcanics rangingfrom olivinc basalt to hawaiite are mostlyporphyritic with combination of olivine andto a lesser extent clinopyroxene phenocrysts.Major element concentration and traceelement abundances were determined forselected rocks from the Haruj area. Theavailable chemical data suggest that the rocksbelong to the alkali olivine basalt associationand are slightly less alkalic than modernalkali suites. There is considerable variationin concentration of the minor and traceelements. The differentiated rocks are likelyto have evolved by fractionation of theundersaturated alkalic basalts at a high levelin the crust, the process being controlledlargely by precipitation of olivine andclinopyroxeno. perphaps aided by differentdegress of partial melting mantle materials orpossibly high pressure fractionation..

To the Sedimentology and faciesdevelopment of Hasawnah formation inLibya

Petr Cepek

The whole sequence of sandstones ofHas&wnah Formation in the area of Jabal alHasa\vnah/Jabal Fezzan, middle part ofwestern Libya/appears to be dominantlymarine in its origin.

Following sedimentary structures,significant for environmental interpretationhave been observed: the cross-bedding, mostfrequent structure at all, is developed inseveral types; high angle cross stratification isa dominant type, having both unimodal asbimodal orientation. Occurences ofbimodal-bipolar herringbone crossstratification are rare. The sharp basedcross-bedding associated with thecorss-bedding with truncated top of sets arc

most frequent modifications. The convolutbedding, speciphic type of graded beddingand parallel lamination are also present.Typical sand bars could be distinguished onmany places. The desiccation cracs have beenobserved too. They are very oftenaccompanied by mechanoglyphs and deepcutted bioglyphic trace fossils.

Facies analysis of all observed sedimentarycharacteristics, particulary of the structuresmentioned above, suggests tide dominantenvironment. The depositional environmenton the transition of subtidal to intcrtidalzone, combined with fluvio-deltaicdepositional influence/supply of terrigenousclastic material/appears to be most probablefacies model.

The Cretaceous/Tertiary boundery in thenorthwestern part of the Hamada alHamra basin in northwertern Libya

J. CHaloupsky, E. Hanzlikovd, B. Zdruba

During the geological mapping organized atthe present time by the I.R.C., Tripoli, in thenorthwestern part of the Hamada al Hamrabasin new geological and paleontologicaldata have been obtained which makepossible to precise the stratigraphic positionof the Senonian and Lower Palcoconelithostratigraphic units the Lower Tfir, UpperT3r and HSd Members of the ZimdmFormation/. The Cretaceous/Teriaryboundary, often discussed in the prevouspapera, is traced close to the boundary of theLower TSr and Upper TSr Members. It isevidenced by a great amount of welldctcrminable macro and microfossils.

The paleogeographic changes near theCretaceous/Tertiary Boundary, the lithofacialdevelopment of marine sediments, mostlycarbonatic as well as rich macro andmicropaleontological assemblages occurringin the delimited lithostratigraphic units aredescribed in the submitted article. Thestratigraphic correlation of the studiedsequence with that of the Sirte basin inCentral Libya is also presented.

Depositional Environment of the Lowerand Middle Devonian Tadrart and UanCaza Formations of the South WestFezzan and their relationship to theunderlying Silurian Deposits

D. D. Clark-LowesThe Tadrart Formation outcrops in a 180

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km north south trending belt to the east ofGhat and through Aouinat to the north whilethe younger Uan Caza Formation is exposedin an area to the east of the TadrartFormation east and south east of Ghat. Themost comprehensive previous work on theseformations is that of E. Klitzsch who haspublished type sections (196x and 1970 inEnglish Translation). Displaying a low angle(1° -- 6°) eastward dip the Tadrart and UanCaza Formations comprise part of thePalaeozoic succession exposed at the westernmargin of the Murzuk basin. Measuredvertical sections systematically recordingrock type (mineralogy and texture), primarysedimentary structures, and biologicalfeatures (trace fossils) have been used inconjunction with photomosaics of continuouslateral exposure in the field to define faciesand to study their geometry. The TadrartFormation with a maximum measuredthickness of 320 mm and the conformablyoverlying Uan Caza Formation (maximummeasured thickness of 4"> m) represent thebroadly transgressive phase of aregressive/transgrcssive cycle in the MurzukBasin from the Silurian (Llandovery) to theMiddle Devonian (Eifelian). Llandovcrianmarine graptolitic shales and siltstones of theTaneszuft Formation are overlain by thecoarsening upwards Acacus Formation,representing a prograding deltaic succession,which is in turn overlain by the DevonianTadrart Formation, which in its lower partcomprises a braided stream delta top setsequence which passes up in the upper partof the formation to a coastal foreshore,shoreface, and proximal offshore sequencecut by tidal channels and offshore shoalsandstones. Lastly the" marine spirrifer andpelecypod fauna of the Uan,Caza Formationclaystones indicate the culmination of thecycle in marine continental shelf conditions.

The lower part of the Tadrart Formationconsist mainly of fine and mediumsandstones though very fine to coarsesandstones are present, the sorting is veryvariable but frequently poorly sorted, andclaystone intraclasts are often present. Thehigh percentage of quartz in the sandstones(quartz arenites), the absence of any detritalcxtraclasts of larger than very coarse sandgrade, the presence of sanstone intraclastsand the remarkable paucity of argillaceoussediments is evidence for a polycyclic source

of the sand grains and a source area whichwas actively shedding detritus fromweathered sandstone fromations throughoutmuch of the period of deposition of theTedrart Formation. Planar tabular crossbedding with sets up to 2.8 m thick butusually less than 1 m thick and frequentintraformational recumbent folded cross bedsis the dominant bedding type in the lowerpart of the Tadrart Formation and thesubsidiary horizontal, homogeneous, rippledand trough cross bedding together withchannel scour and fill features indicate anenvironment of great fluctuation of Howstrength. The recumbent folded cross bedsand other deformed beds (slumping andconvolute bedding are present) suggest rapiddeposition and the entrapment of intersticial ,water the presence of which allows the bedsto undergo plastic deformation by thesemihorizontal shear of sediment ladencurrents on their upper surfaces, and theexpulsion of which on subsequent burialresults in fluidized beds. The bedding typesare grouped into those interpreted as being Iformed by high water stage braided streambedform migration, i.e. transverse bar andlinguoid bar downstream migration, byaccretion on bar avalanche slopes, and thoseformed by low water stage accretion andmodification processes and channel scourand fill. Channels of up to 2"> m in widthbasal scour deposits lying with cross cuttingrelationship to lower beds and containingangular intraformational elaystone andsandstone clasts are abundant in the upperpart of the lower 1 SO m of the formation.They are interpreted as lateral accretion •deposits in low sinuosity laterally shiftingbraided delta distributory channels. Theupward transition to this facies represents ashift from proximal to distal fluviatilesedimentation and the initation of someminor meandering. Palaeocurrent directionsfrom cross bedding dip azimuths within thefluviatile facies indicate unidirectional flowto the west and north west with a range of13"S°. Finer grained sediments (very finesandstones and siltstones) containing marinetrace fossils (Arthrophycus, Skolithos andothers) are present in 2.*> m to 20 m unitswithin the succession of fluviatile deposits.An interpretation of these incursions into thecontinental sequence based upon a highconstructive elongate braided delta complexmodel (interdistributory bays open to the sea

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generate thin lenticular marine fades withincontinental fluviatile deposits) is comparedwith a model which requires (unlike theformer model) an alternation in detrital inoutto the delta complex to explain the marineincursions, which are interpreted as marinetransgressions consequent upon reduced orabsent detrital input. The upper 170 m of theTedrart Formation consists of mainly fineand silty fine sandstones with horizontalbioturbatcd bedding. Sublittoral and littoraloffshore, shorefacc and foreshore depositsare recognized with horizontal burrows sandtrails (Cruziana Ichnofacics) in the deeperwater deposits through to vertical burrows(Skolithos Ichnofacies) in the shallower moreturbid water deposits. Cross cutting these aretrough cross-bedded intertidal to subtidalchannel bodies composed of slightly coarsergrade sand. A laterally persistent S m thickmassive horizontally bedded andcrossbedded fine sandstone unit, withabundant indistinct pelecypod shell moulds,within the thin bedded bioturbatcd coastalsandstones and siltstones is interpreted as alenticular offshore shoal sandstone. Theevidence of transported and reworkedpelecypod snails, the polydirectional currentindicators, and the absence of channelingdistinguish it from other massive sanstonebodies in the section. The dominantpalaeocurrent direction in this upper part ofthe Tadrart Formation is to the south with astrongly bipolar subsidiary east-westcomponent. This probably represents anonshore-offshore bipolarity a strong currentlongshore dirft to the sout. The Uan CazaFormation is an offshore clean, siltfrecclavstonc deposit. It contains siltstonehorizons displaying current ripples andin-drift climbing ripple lamination indicativeof subtidal sheet deposits which may resultfrom eceptional tides and consequentsediment-laden subtidal currents.

Finally a palaeogeography is proposedwhereby the sediments studied are those laiddown on the cast and wouth east margin ofan epicontinental sea (opening out to thenorth off the African Craton) where majordetrital influx and rapid sedimentation hasbuilt progreding delta complexes during theSilurian and Lower Devonian periods(Acacus Formation and lower part of TadratFormation) the upper parts of which arereworked later in the Lower Devonian togenerate the coastal sandstones of the upper

part of the Tadrart Formation. Reduction ofrelief and peneplanation in the source area tothe south east caused decreased sedimentsupply and the transgressive shales of theI lan Caza Formation were laid down. Adepocentre to the west or north west of Ghatis indicated rather than at the centre of thepresent Murzuk Basin.

Isopachs of the Silurian TaneszuftFormation also suggest a depocentre well tothe west of the west of the Murzuk Basinaxis. As palaeocurrent directions fromPalaeozoic fluviatile sequences in the KufraBasin to the north west of the Tibesti Massifalso indicate a source to the south east theinfluence of this massif upon the Palaeozoicsedimentation is questionable. Uplift of thesource region and the sediment generatedfrom its erosion may be the major controllingfactor in the Silurian and Devonian depositsof the study area.

Geology of a stratigraphic giant - TheMessla oil field

//. J. Clifford

The Messla Oil Field is the most recentaddition to the imposing list of some twentygiant fields discovered within the prolificSirtc Basin of Libya. The field, discovered in1971, is located in the southeastern portiohof the Sirte Basin, approximately 40kilometers north of the supergiant Sarir OilField. Although in an early stage ofdevelopment the field is estimated to containapproximately three billion barrels oforiginal oil-in-place. The essential trappingmechanism is the updip truncation of theLower Cretaceous Sarir Sandstone on abroad plunging nose.

The maximum oil column is 2S0 feetproductive from an average depth of 8800feet over a 200 square kilometer area.

The Messla Field is a seismically definedstratigraphic accumulation located on theeasterly plunging nose of an ancestralbasement ridge. The productive unit is theLower Cretaceous fluviatile Sarir Sanstonewhich wedges out westward on thePrecambrian Basement and is truncated by aprofound unconformity at the base of thecapping Upper Cretaceous marine shales.

The reservoirs consist of two Sarir sandsseparated by a continuous shale bed.Porosity values average 16 percent and thepermeability, four hundred and fifty

23

millidarcies. Production as of early 1978 is inexcess of 100,000 barrels per day of 40° APIgravity oil with a cumulative production of45 million barrels.

Synthesis of the Lower PaleozoicPalynostratigraphyof northern Africa

F. H. Cramer & M.D.C.R. Diez

The interval beginning at the Cambrianthrough the Devonian transition in NorthernAfrica (Morocco, Algeria, Tunisia, andLibya) and areas in its immediatepaleovicinity (Brazil, Iberia, SE Turkey, andArabia) generally yield very well preservedpalynomorph assemblages in rocks withthermal alteration indexes that place them atlevels better than the upper limit of the oiland gas window.

Based in points of arrival, acmes, horizonsof co-extinction, and homotactic sequences, apalynostratigraphic succession with fair toexcellent chronologic precision has beenconstructed which is valid for this entireregion. Acritarchs s.l., chitinozoans, andmiospores (for the Silurian and Devonian),have been used. The region is now known tobelong to the same series of succeedingpaleophytoplankton provinces throughout upto the early Devonian so that correlationseven over very long distances presenthomotaxis even in very detailed aspects;from the middle Devonian onward theincreasing palynologic endemism precludessuch long distance correlations.

Hydrogeological Conditions of theNorthern part of the Western Desert,Egypt

M. S. Diab • F. A. Hammad -5. M. Aiwa

The main objectives of this study are toasses in general aspects the quantity, qualityand most promising aquifers for further landreclamation projects. Neddless to say thatthese objectives neccessitate the thoroughexamination of the relevant hydrological,geological, geophysical observations.

The p r i m a r y r e c o n n a i s s a n c ehydrogeological studies done on the northernPart of the Western desert of Egypt revealsmany new foundations. The area was foundto comprise the following aquifers:

(1) The dune water table aquifers.(2) The elevated water table aquifers.(3) The fissured limestone water table

aqufers.(4) The Artesian aquifers.

Syenite and Carbonatite Plugs West ofJabal Awaynat, Southeastern Libya

A. K. Doughri - D. S. Sinha & R. S. Yeats

Two syenite plugs, each nearly 4 km indiameter, intrude nearly flat-lyingCretaceous sandstone in southeastren Kufrabasin 100 km west of Jabal Awaynat nearthe Libyan-Egyptian-Sudanese commonborder. Forceful intrusion was accompaniedby tilting outward of the sandstone to dips ashigh as 70° and by conjugate shear fracturingof the sandstone, indicating maximumprincipal compressive stress radial to thecentre of each plug. Magnetic anomaliesrecorded at the intrusive borders suggest theintrusive contacts are near-vertical,discordant to sandstone bedding at depth.The syenite is lcucocratic and fine to mediumgrained with local vertical foliation. Pods ofbiotite-apatite rock, sanidinite and magnetiterock are most abundant in the eastern body;locally the apatite rock contains nepheline.The central part of the eastern body consistsof carbonatite agglomerate 500 metre indiameter, the first carbonatite rockdiscovered in Libya. The agglomeratecontains rounded to sub-rounded fragmentswith clinopyroxene, green hornblende,plagioclase, brown biotitc, magnetite, calcitcand potassium feldspar in an altered glassmatrix. Sovite occurs as fragments ofequigranular calcite rock in agglomerate anda small dike intruding agglomerate; calciteoccurs with potassium feldspar and brownbiotite. The plugs contain up to 730 ppm Ce,700 ppm, 7200 ppm Ba, 1330 Zr, 2100 Nb,900 ppm Y, 1600 ppm Sr, 340 ppm Rb, 100ppm U and 950 ppm Th; theseconcentrations vary widely. The plugs,characterized by local zones of high magneticsusceptibility and moderate to- strongradioactivity, are in contrast to the largesyenitic and granitic ring complexes of Jabalal Awaynat and Jabal Arknu, which lackcarbonatite and concentrations of rareearths.

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Groundwater in Wadi Shati, Fezzan;a Case History of ResourceDevelopment

Laszlo Dubay

By late 1973 the Council for LandReclamation and Development entrustedItalconsult SpA with the executuion of a3000 ha, land reclamation project in theWadi Shati Brak- Eshkeda area, Fezzan,.

The agricultural development was basedon the groundwater resources. Earlyhydrogeological investigations indicated theCambro-Ordovician sandstone formations asthe most likely source of groundwater,suitable for large scale development. Thewater wells drilled subsequently to provideirrigation water and aquifer performancemonitoring facilities confirmed theexpectations and idenfied in theCambro-Ordovician sandstone one of themost important regional aquifer systems ofLibya.

In the course of the subsequenthydrogeological studies and after the firstappraisal of the hydraulic characteristics ofthe aquifer system, a groundwater model wasbuilt and operated with different hypothesesof additional groundwater extraction from61 x 106 to 200 x 106 nrVyear, to verifythe soundness of the design of irrigationwells which were to be completedsubsequently. According to the forecastdrawdowns resulting from modeloperations the exploitation of irrigationwells appeared possible for a period byfar in excess of the 3*> years periodconsidered.

The regional groundwater model,embracing nearly 125,000 km2 was of theR/C digital-analog type, using the AdvancedStatistical Analysis Program (ASTAP), anInstalled User Program of IBM.

The first part of the agriculturaldevelopment project became operational inlate 1975, and by mid 1977 the whole areawas under irrigation. The effects of theknown amount of new groundwaterextractions were closely followed for a periodof more than two years and are still underscrutiny; they enabled a comparison to bemade between effective and forecastdrawdowns. The exploitation period revealedin general a good correspondence betweenforecasts and effective situation, the

measured drawdowns being slightly less thanthose envisaged. Of particular importance is,however, the fact that a new dynamicequilibrium occured in a period of less thantwo years after exploitation started, incontrast with the model results which showeda new quasi equilibrium only after 20-2")years of operation. This very favorablesituation points to the paramount importanceof the unconfined portion of the prevailinglyartesian aquifer system, which acts as acompensating reservoir on the groundwaterextractions practiced in nearby areas.

The new groundwater development in theBrak-Hshkeda area has proved to be anexcellent testing ground for the quantitativeassessment of further development potentialof the Cambro-Ordovician aquifer systemand, at the same time, it allows to drawimportant conclusions on the mostadvantageous locations for furthergroundwater exploitations. The latter shouldbe preferably located in the vicinity of theJebel Fezzan, near to the outcrop area ofCambro - Ordovician saudstoncs, wherewater-table conditions prevail.

The hydrogeochemical characterisationof groundwaters in the Sirte basin,using Strontium and other elements

W. M. Edmunds

Strontium has been used an exploration tool,along with other minor elements duringevaluation of the groundwater resources ofthe Miocene and younger aquifers of theSirte Basin. A wide variation in Sr2+ from <0.1 to 29 mg/1 is found and this variation canbe related to lithofacies, reactions ofcarbonate and other minerals and to overallsalinity changes. Strontium is therefore avery useful indicator element which has beensuccessfully used, in conjunction withhydrogeological information and thegeochemistry of major elements to defineflow paths and groundwater evolution andorigin.

The Sr2+ has been used to distinguishmarine-derived from non-marine derivedMiocene groundwaters and thence to tracethe extent of leakage from one aquifer toanother and to define hydrogeochemicalfacics within the main aquifers. In this paperthe relevant hydrogcochemistry of strontiumis examined and the extent of attainment ofequilibrium with carbonate and sulphate

minerals and discussed. Lithium, boron andfluorine ha\c also been used in a similarmanner as potential trace elements todetermine groundwater origin. The likelycontrols on the distribution and mobility ofthese elements in the Sirte basin aquifers arediscussed in terms of mineral equilibria(fluorite) and other reactions.

The significance of these and other minorelements in relation to water supply andwater use in Libya is briefly reviewed.

Investigation of radioactivity in thewater Welis of Tripoli Area

E. A. tissu - A. A. Missullati andK. M. l-A-Sherief

This paper represents the prelimenaryresults of the initial stage of a researchproject concerning a large scale radiationsurvey of Libya. In this study samples ofwater from 68 (recorded) wells and springsin the metropolitan area of Tripoli wereinvestigated by means of an automaticspectrometer. In this spectrometer betaradiations are detected by the liquidscintillation technique and the gamma-raysare detected by a well type 3" x 3" Nal (Tl)crystal technique. Results of the analysisindicated that 34 wells are of high tritiumcontents. This will stand as a record ofi n t e r e s t for t h e g e o l o g i s t s andhydrogeologysts in studying the localvariations of the isotope composition of thesubsurface water and the nature of rechargefrom one season to another. Healthphysicists will be interested in the hazardscaused by these radioisotopes.

The geological interpretation of agravity map of northern part of Maradagraben (Sirte basin, Libya)

Salah I. L-'A-Batroukh & Ahmed S. Zeniani

A Bouguer anomaly map of the northernpart of Marada graben is presented andinterpreted. The main features of the maparc: (1) A negative anomaly trending NW—SE approaching — 16 mgal in the SE thendecreasing gradually up to — 2 mgal in theNW. (2) Steep anomaly gradient on bothsides of the negative anomaly indicating faultlines.

(3) A narrow flanking areas of strongpositive anomalies ranging from + 7 to + 1 7mgal on both sides of the negative anomaly.

These anomalies are all superimposed on astrong regional gradient of 0.3 mgal/km tothe south-west.

The negative anomaly is due to densitycontrast between the low density of thesediments and the high density of thebasement. The positive belts on both sides ofthe negative anomaly are interpreted ashorsts structures characterized by basementrocks at shallow depths.

The diminishing of the negative anomalytowards north-west is attributed tointerruption of a very strong positiveanomaly (3*> mgal) in the north.

Structural sections across the graben arepresented and compared with gravity modelscalculated by computer. Both show a verygood agreement.

Monitoring the Deserts from Space

I'-'amuk El-Baz

Although docits occupy approximately20% of the landmasses of the Earth, theyremain one of the least understood of all itsfeatures. Among the reasons for this is thefact that deserts cover immense areas whereharsh conditions prevail. Their remotenessand inaccessibility preclude their study byconventional means. However, remotesensing from space provides a uniqueopportunity to study monitor the desertenvironment. This is particularly truebecause deserts must be studied on aregional basis and because climaticconditions arc nearly always favorable tomonitoring from space.

Available data from manned spacemissions and Landsat satellites show that thereflectance properties of desert surfaces areindicative of the composition of the exposedrock rubble. Examples are given of distinctcolor zones in desert photographs thatcorrelate with the amount of sand,desert-varnished pebbeles, and clay mineralsin the exposed soil.

Similarly, it has been shown that desertsands become redder as their distance fromthe source increases. This is due to the factthat individual sand grains become coatedwith an increased amount of iron oxides withthe passage of time. This property is clearlydemonstrated in the Sturt and Simpsondeserts of south central Australia, the NamibDesert of southwest Africa, and the EmptlyQuarter of Saudi Arabia. Color zones in

26

space photographs of these areas can be usedto delineate relative age zones within thesand fields.

Space photographs also provide anefficient way to monitor the extent ofvegetation in arid regions. Photographs takenof the same area west of the Nile Delta byGemini (196~>) and Apollo-Soyuz (197"S)astronauts clearly delineate the success ofone desert reclamtion project and the lack ofprogress in another. Landsat images of anarea in southeastern Libya, which were takenat various times, show the stages of progressof a reclamation project based on theutilization of underground water.

These and other examples confirm theutility of space photographs and Landsatimages in the investigation of desertlandforms and of reclamation projects.However, the need exists for a completesurvey of all parameters of the aridenvironments that can be successfullymonitored from space; for example, theparameters that can be indicative ofdesertification, particularly in large regionssuch as the African Sahel. Similarly, the needexists to categorize the photocharacteristicsof areas that exhibit good soil and hence canbe reclaimed from the desert.

Today, the lack of meteorological dataprohibits a full understanding of the desertenvironment. Space age technilogy canremedy the situation. Meteorological stationscan be placed in remote areas to collect dataand beam them to orbiting communicationssatellites. The latter can transmit the data toground stations for analysis and synthesi.Monitoring the deserts from space in thisway will help us utilize more of the land areaof the T'arth for the benefit of mankind.

Utilization of Orbital Imagery andConventional Aerial Photography in theDelineation of the Regional LineationPattern of the Central Western desert ofEgypt with a particular Emphasis on theBahariya Region

//. A. lil-Etr and A. R. Moustafa

Multi-band landsat images (scale1:1,000,000 and l:S00.000) were used todelineate the photo lineations of an areaapproximating 281,280 sq km in the centralWestern Desert. A total of 481 lineamentsand lincars were detected of which 197 linearfeatures are in the Bahariya Region

(approximately 4-1,1 "50 sq km). Forcomparison purposes, aerial photographs(scale 1:60,00) and mosaics (scale1:100,000) were used to delineate thedetailed lineation pattern of the Central partof the Bahariya Region (approximately18,-530 sq km),. In this case, a total of 81326linears were identified.

A multi-stage procedure was adopted forthe recgnition of lineations on both orbitalimages and aerial photographs. All suchlineations were later sorted out, on reliabiltybasis, into three orders and were annot at ed,recorder for convenient equql unit areas thenespressed in frequency diagrams and, incases, isopleth maps.

The central Western Desert in the presentstudy represents the central (mainly Eocene)limestone plateau of this Desert and includesthe important Oases of Siwa, Bahariya, andFarafra. Miocene carbonate rocks areexposed, kowever, in Siwa Depression andCretaceous clastic and carbonate rocks arepresent in the Bahariya and FarafraDepressions respectively. Besides, Oligoceneclastic units are also reported in the BahariyaDepression.

The present study proved that the centralWestern Desert regional photo lineationpatternis characterized by a strong degree ofpreferred orientation in the trends NW andENE. Local deviations, however, are alsoreported in the Bahariya Region. These areattributed mainly to lithostratigraphiccontrol.

Space images proved their value indeciphering regional lineations that may beobscured and (or) mutilated in the largerscale aerial photographs and mosaics. Suchlineations proved to control, to as substantialdegree, the shapes of the Siwa. Bahariya, andFarafra Depressions. Aerial photography,however, is still, and believed will continueto be, an indepensable medium of dataacquisition that provides significant details ofdirect bearing on the local and semi-regionalscales and provides a high resolution mediumfor checking the details and "groundmeaning" of regional features on spaceimagery.

Inter-tidal and Storm Sedimentationfrom Wadi al Qattarah Member,Ar-Rajmah Formation (Middle Miocene),Jebel al Akhdar

A. S. El-Huwat

27

The occurcncc of tidal flat and saline ponddeposits within the dominantly carbonatemiddle Miocene Qattarah member(Ar-Rajmah Fm.). in Jcbel al Akhdar area,is in response to the influence of astorm-formed barrier beach. Tidal flatsdeveloped behind the barrier and on themarginal areas between saline Ponds, thatwere spasmodically fed by sea water duringstorms.

Carbonate - Terrigenous CyclicSedimentation and Palaeogeography ofthe Marada Formation (MiddleMiocene), Sirte Basin.

A. S. El-Ha war

The Marada Formation is a transgrcssivesequence that consists of carbo-nate-terrigenous cyclic succession. Sevensedimentary 'fades are distinguished: 1)Calcareous sandstone (estuarine channel), 2)Calcareous shale (lagoon), 3) Cross-beddedsandy grainstoe (tidal inlet, channel, anddelta); 4) Cross-bedded grainstone (barrierbars and beaches); 5) Dolomitic limestone(tidal flat); 6) Wackestone (marine bank); 7)Marl (marine deltaic fan). In cross-section,these fades arc arranged in three successiveinformal depositional members: a) basalestuarine; b) lagoonal-barrier complex and c)open marine.

The palaeogeography of the period wasdominated by inherited NNW-SSE trendingZelten Swell; which separates two parallelareas of subsidence, the Marada and EastZelten Basins. Over the swell, high energycarbonates accumulated; and in the basins,lower energy shale, marl and wackestoneattain maximum thickness. Palaeogeographywas maintained by syn-depositionaldifferential subsidence; which was attributedto differential compaction of shales andmarls, that was possibly, enhanced byspasmodic tectonic movement of pre-existingburied structures.

Cyc l i c c a r b o n a t e - t e r r i g e n o u ssedimentation evolved through interplay ofthe rate of sea level risel, differentialsubsidence, and palaeogeography. Thesefactors influenced trapping and releasing ofterrigenous sediments in the nearshore area;that caused corresponding re-starting andshutting off carbonate productivity andtransgression in the offshore area.

Biostratigraphy and Paleoenvironmentof Maastrichtian (upper CretaceousForaminifera from Northcentral andNorthwestern Libya

B. A. Eliagoubi and J. Dan Powell

The youngest Cretaceous foraminifera]faunas in Libya occur in the Sirte Basin andenvirons. These faunas consist of twenty-sixcosmopolitan planktonic and ben thonicgenera and three, more restricted generaI O m p h a I o c y c I u .i, S i d e r o I i t e a ,Siphogenerinoids) belongong exclusively tothe Tethyan Realm. Forty-six species andvarieties of foraminifcrs have been recordedand described by Eliagoubi (1978).

Two assemblage zones, The Zone ofGlobotruncana fornicata and the youngerZone of Globotruncana conica are proposed.Two subdivisions of the latter are thatGlobotruncana gansseri Subzone and theGlobotruncana contusa Subzone, which aretraceable across most of northern Libya.These zones provide precise correlations withthe type Maastrichtian in Holland, withNorth America and with other parts of theworld.

Three rock units, Waha Limestone, KalashLimestone, and Lower Tar Marl, contain theMaastrichtian faunas. These formations havebeen studied in the subsurface of the SirteBasin and at the Wadi Tar and Dor Talahsurface localities west of Sirte Basin.

Suggested paleoenvirnments for the lowerMaastrichtian limy sequence (Waha andKalash limestones) are shallow shelf andpossible offshore carbonate banks. Theupper argillaceous beds (lower Tar Marl)reflecte a general deepening of the water anda shift to an outer shelf-middle slopeenvironment. The impoverishment ofmiliolids in the shallow-depth limestones isenigmatic, and may indicate specialrestrictive conditions, perhaps related ofoffshore shoaling over faulted bottomtopography.

Kufra Pleistocene Lake Its Evolution &Role in the present Day LandReclamation

/. M. Elramly

The present paper forms a part of a largescale systematic investigations on WaterResources Development in Kufra Basin,presently undertaken by the Secretariat of

28

Dams and Water Resources, Tripoli.By the application of Landsat imago

interpretations for Kufra Basin, and as wellthe ground observations by the author duringhis trip to the region in November 1977,some scientific evidences were brought toour knowledge and helped in the preparationof this paper.

Actually, the study involved the expectedpaleoclimatic conditions which wereprevailing within this part of the GreatSahara during the Quaternary time.Reconstruction of the Pleistocene lakeshoreline is presented in this work. Thepresent day lakes of Buhayret Buwaymahand Bahr Ilet Geith located NE & West ofKufra Town respectively, are remnants of theprevious large lake.

Evolutionary stages of the lake based onthe presence of fresh water limostene layers,the finding of the Melania tubercolaiaPleistocene fossil, and the morphologicalfeatures of the Kufra depression added muchlight to the present study.

From shallow borings in the reclaimedareas of the Kufra Production Project, it isobvious that cyclic fluctuations in the climateresulted in the deposition of intercalatedcalcareous and loose sand layers withvariable thicknesses whitin the examinedprofiles. This phenomena may tesult aftersome time in the building up of a shallowwater table, from return irrigation water inthe irrigated fields, in both Kufra Productionand Settlement Projects. The present studyincludes some guidlines for future monitoringof shallow water tables. This will bring earlyattention to both projects personnel, beforeany drainage problem could occur.

Similarities between other inlandQuaternary Lakes in Africa and SouthwestAsia and the Kufra Lake are outlined in thiswork.

Stratigraphy and Lithofacies of theContinental elastics (upper Jurassicand Lower Cretaceous of Jebel Nefusa,N. W. Libya

A. Y. - El-Zouki

The stratigraphical relationship and thevarious lithofacies of the Chicla, Cabao, andChameau Mort Formations was undertakenin the present study. The Chicla Formation(Albian) shows lithofacies variation from oneregion to another. It mainly comprises of

supermature quartzarenite Sandstone andconglomerate units which were depositedunder differing alluvial conditions. In theeastern region the Sediments of the ChiolaFormation were laid down by turbulentcurrent activitly in a braided channel,whereas in the western region the Sedimentswere deposited by a large meandoring river.

The Cabao Formation (Wealen) comprisesof essentially Sublitharenite Sandstoneslocally containing thin horizons rich invertebrate fossils. In this study the vertebratefauna provides new stratigraphical evidence.They strongly support a wealden (L.Cretaceous) age for the cabao Formation.The Chameau Mort Formation (U. Jurassic)displays two main lithofacies, a lowersubarkosic sandstone facies and an uppergypsiferous mudstone sequence. Althoughthe plant fauna described from the ChameanMort Formation yielded no index fossils, it isseparated from the Cabao Formation by theShakshuk Limestone of Oxfordian —Kimmeridgian (U. Jurassic) age, and itsucceeds the Middle Jurassic TacbalLimostone. This means that the ChameauMort Formation must be Callovian —Kimmoridgian (U. Jurassic) in age. Severalprevious workers considered these clasticsequences as one formation. The mainconclusion drawn here is that the Chicla,Cabao, and Chameau Mort Sandstones arethreee separate stratigraphic units.

Depositional Environments of theChicla, Caboa, and Chameau mortformation as Revealed by scanningElectron Microscopy

A. Y. El-Zouki

The Chicla, Cabao, and Chameau MortFormations are Mesozoic continental clasticsequences exposed in Jebel Nefusa,North-Western Libya. The ScanningElectron Microscope analysis of sand grainsprovided useful criteria which can serve inthe distinction between these clastic depositsand also for recognition of depositionalenvironments.

The sand grains of the Chicla Formationarc dominated by v-shapes, impact pitting,and conchoidal breakage patterns. Thesefeatures are diagnostic of a fluviatileenvironment.

The sand grains of the Chameau MortFormation are distinguished by several

29

aeolian grain surface features such asdish-shape concavities, rounded grains andsmooth surfaces.

The sand grains of the Cabao Formationshow several mechanical patterns similar tothose observed on sand grains from theChicla and the Chameau Mort Formations.This may indicate a mixed continentalenvironment where alluvial and aeolianconditions alternated.

Structure and Strain Determinationsbetween Azizia and Garian/Tripolitania(Libya)

J. i.rdmunn

Investigations of the structural patternsand in-situ rock straine in the area betweenAzizia and Gar i an ( l o n g i t u d e s32°1071atitudes 13°00' - 13°l.->') have beencarried out in 1976 and 1977. The mainobjectives were to determine

a) the present tectonic stress field bymeans of the new overcoring method

b) the paleo-stress regimes from LowerTriassic to Upper Cretaceous by means ofmany small-scale tectonic features (such as ofjoints, stylolites, slickensides, faults, dikesand strike/dip).

The dominant structural features of theinvestigated area are orientated in anorthwest — southeast direction (140°). TheRas Hamia, Azizia and Bu Sceba formationsreveal tectonic features that result from amaximum horizontal compressive stress ofnorthwest — southeast direction. Thestructure of the Jurassic Bu Gheilandolomites imply an east — west (90°)orientated compressive stress. TheCretaceous Ain Tobi Formation has beendeposited during a period of tectonic quiet.From Oligoccne up to Early Pleistocene the140° orientations of Triassic age have beenrejuvenated, accompanied by intrusive andextrusive volcanism. This stress-fieldpreceded the Recent active maximum stressthat is Northeast — southwest (i0° to 70°)orientated.

At a few sites of in-situ strainmeasurements maximum horizontalcompressive stress is still orientated in thenorthwest — southeast direction. FromRecent rock strain investigations a boundarybetween two different Recent tectonicregimes is supposed running from Azizia toGarian.

Determinations of residual stress are inaccordance with the Tertiary northwest —southeast orientated stress — field (140°).The residual maximum horizontalcompressive stress has been revealed bysecond overcoring.

Stratigraphic Nomenclature of the preupper Cretaceous Mesozoic Rocks ofJabal Nefusa, Libya

A. N. Fatmi, B. A. Eliagoubi & O. S.Ha mm it da

The nomenclature, unit boundaries andage limits of the Upper Cretaceous Mesozoicof Jabal Nefusa are discussed.

A new group namely Jado Group toinclude Cabao and Kikla Formations, andtwo new members namely Al Qabil Member(Upper) and Sart Buon Member (Lower) ofAl Azizyah Formation are proposed.

The Tiji Group proposed by Hammuda(1969) and formally introduced by El Zouki(1976) for the Tiji Formation of Burollet(1963) is retained to include ShakshukFormation, Chameau Mort Formation withGiosh shale members and Tacbal Formation.The Tiji Group is overlain by Jado Groupand underlain by Bir el Ghenam Group.

The Bir al Ghanam Group of Christie(19*n) is considered a valid name consistingof two formations — an upper AbergheFormation with one Bu en Niran Member inthe lower part and a lower MahmelFormation of Burollet (1977). The BuGhaylan Formation is considered a faciesequivalent of lower part of MahmelFormation.

The Kurrush Formation is divisible intotwo members (not named), the uppermember (mixed clastic and carbonate)corresponds to the lower division of AlAzizyah Formation of Burollet (1963) andFatmi (1977). The lower member isdominantly a clastic unit.

Volcanics of Jabal Assawda, Libya

Frantiiek Fediuk - FrantiSek Waller

During the geological mapping, organizedby IRC, the volcanic complex of JabalAssawda was studied. This complex, whichcovers area of approximately 6,000 squarekilometers is situated in the central part ofLibya, south of Al Jufrah.

The bedrock of volcanites comprises a

30

complex of sedimentary rocks dated hackfrom Maastrichtian to probably Oligoccneage. At the northwestern margin of thevolcanics enolitcs of cristaline schists werefound. These represent fragments of thenorthern promotories of the African Shield.

Morphologically the Jabal Assawdavirtually forms a plateau composed ofmultiple, criss-crassing lava (lows, out ofwhich younger volcanic cones, shieldvolcanoes and intrusions emerge. Theobserved thickness of the basalt flowscomplex totals up to 100 meters. The largestshield volcanoe has 10 kilometers indiameter and the highest peaks reach up to800 meters a.s.l. Basalt cones are veryfrequenty, and their diameter is from 100meters to 1 kilometers mostly.

Intrusive types consists either of basalticrocks similar to the subcrustal volcanics, orof subvolcanic intrusions of a plutonicappearence. The former category occuringmainly in the form of plugs, dikes and sills,the subvolcanic intrusions can be divided intotwo subtypes: intrusions penetrating into theflood basalts and intrusions into the shieldvolcanoes and volcanic cones.

Pyroclastics were found only sporadically.The effusives as well as fine grained rocks ofintrusions are basalt rocks, but purelyaphync types were not found. In the mostcases, phenocrysts are represented by olivineand by less conspiceous augite. The groundmass is usaul ly a m i x t u r e ofp l a g i o c l a s e / a n o r t h i t e 6 0 % / andclinopyroxene. Less often olivine, oremineral and vitreous mesostase occurs.

The mineral compostion of the subvolcanicintrusions is basically identical with that ofeffusives. Some types contain a small amountof low sanidine. The porphyric texture isdeveloped in this bodies in a margin partonly, central parts are coarse grained, withgabboic texture.

According to the classification diagramtotal alcalis: SiCh which is recommended bythe IUGS Commision for Igneous RocksClassification in 1977, most of the chemicallyanalysed samples falls into olivine basaltgoup and occasional can be classified asbasanite, tholeiitic basalts, alcaline picritesand theralites. In the AFM diagram plots ofbasalts from the flows, cones, shieldvolcanoes and intrusions suggests a lawdegree of fractionation of this rocks. On thecontrary, a more advanced differentiation can

be assumed for the subvolcanic intrusions.The survey of trace elements content

shows a global similarity with thecorresponding results of the Gharyan areaAlmond et al. 1974/ with exceptions of thehigher Rb content in the rocks from JabalAssawda.

The Jabal Assawda is similar to otherLibyan volcanic complexes, spatially relatedto crossing of the old Paleozoic structuralelements/direction NNW-SSE/ and the youngPaleozoic to Mesozoic structuralelements/direction ENE-WSW/. Thedistribution of central eruptions andintrusions follows the above mentionedstructures. The age of volcanics of JabalAssawd£ range between 10."j and 12.3 m.y.,according to previous authors.

Lherzolite nodules in the JabalAssawda

Franii.ick I'ediuk

Detail studies of basalt volcanics werecarried out during the geological mapping onbehalf of the Industrial Research Centre.Tripoli.

Ultramafic nodules of Ihcrzoliticcomposition, occuring wordwide in alkalibasalts and related rocks, are also knownfrom Libyan Tertiary/Quaternary volcanicprovinces. They have been mentioned fromthe Ghirian \olcanica by Altomnd et al. 1974and schematically presented /not verycorrectly/ on a sketch map by Forbes andKuno 1967. It is highly reasonable tosuppose that the other volcanic areas. JabalAssawda, Haruj. Jabal Eghei and Tibesti.should them contain as well. For the JabalAsswda' area, this presumption has beenproved as a matter of fact.

The localities of nodules are numeroushere. In some of them, the nodules arepresent scarcely, but in others they areabundant. The most remarkable locality,extremely rich in nodules, is situated I ,"5 kmN of Oualait Ferjan hill, 11 km SW of Socna.It is a slowly wedging basaltic sill ."5 up to 20m thick which consist of three parts, theupper and lower being almost nodule-free,but the middle one containing more nodulesthan the host basaltic rock. This nodule-richpart seems to enable a look inside therelations between nodules and the basalt: thebrecciated peridotite is cemented by thebasalt apparently formed by partial melting

31

of the former rock. During the intrusion, thenodules lacking marginal parts acted aslubricant.

In all Jabal Assawda' localities, thenodules occur exclusively in basaltic dikes,sills, necks and lavas of volcanoes of centraltype, they have not been ascertained in lavaflows of fissure eruptions. Their mineralogyis very uniform. The predominant mineral isolivine with the range of Fo content between88,4 an 91,2%. It amount mostly notexceeding 30% there occur pyroxenes, fromwhich the orthopyroxene containes En 90.1 -91.1%. Comparatively high AI:03 content inclinopyroxene /up to 6.29%/, as well as othercriterias, indicate a very deep level ofequilibration. Clinopyroxene is also the maincarrier of CnOj. Following lherzolite vs.basalt trace elements rations have beenfound Cr= 4.9, Yb= 2.0, Co= 1.8, Rb= 0.5,Th= 0.3, V= 0.3, Y= 0.2, Ba= 0.02 etc.

Evidence for a passage betweennorthern and southern proto-Atlantic inAlbian times

Reinhard Forster

Since Wegcner presented his concept ofcontinental drift much efforts have beenundertaken to date the first open seawaybetween n o r t h e r n and sou thernproto-Atlantic. Recently collected faunasfrom SE-Nigeria reveal a first passage inLate Albian times. This is supported by thehigh degree of similarities between ammonitefaunas from Nigeria and northern Africa,and a minimum of endemic species not onlyin faunas from the the Late Albian, but fromthe Lower and Middle Ccnomanian.

Particularly convincing is the occurrence ofa new species of the genus Salaziceras andthe distribution of this genus and ofrepresentatives of the Stoliczkaia africana(Pervinquiere) group. The genus Salazicerasin known only by a small number ofspecimens from the Lower Vraconian ofSE-France, Hungary, Tunesia and southernMorocco. Specimens of the Stoliczkaiaafricana group have been recorded fromwestern Europe, northern Africa, Texas,Brazil, Angola and Zululand. This westernTethyan distribution and the absence ofrecords from the Middle East, Madagascar,India and East Africa suggest a western shortcut. This is more probable than a longmigration along the East African coast and

via the Cape Seaway. There are nosignificant arguments for a direct"trans-Saharan" passage at this time.

The record of the endemic south Atlanticgenus Elobiceras in a drilling core from theIvory Coast Basin, and the close affinities ofEarly Upper Albian faunas from Angolawith those of northern Africa, Texas andMexico even suggest an earlier open seawayin Early Upper Albian times. One of thereasons why Tethyan ammonites occurredearlier in time in greater quantity and varietyfarther to the south than southern Atlanticspecies did migrate to the north might be theexistence of unfavourable current systems inthe early Altantic.

Pan-African Age Granites ofNortheastern Africa: New or ReworkedSialic Materials?

Paul D. Fullagar

Pan African ages for granitic rocks ofnortheastern Africa often have beenattributed to remobilization of Archean sialiccrust. However, an ensialic origin for theserocks is incompatible with the limited Srisotopic data available for this region.

Six plutons representing several differenttypes of post-tectonic alkali granite from theRed Sea Hills region of eastern Egypt yieldRb-Sr whole-rock isochron ages of '595 to568 m.y. (These crystallization ages arebased on a Rb«? decay constant of 1.419 xlOn yr 1.) Five of these Egyptian YoungerGranites have initial Sr»7/Sr «6 rations of0.7016 to 0.7025; one pluton has an initialratio of 0.7061. These low rations (-0.702)could not be produced by mobilizingArchean sialic crust ~600 to 550 m.y. ago,but could be produced by derivation of thesegranites from a lower crust or upper mantlewith a low Rb/Sr ratio.

Rb-Sr isochron data for portions of thecalcaklaline Ben Ghnema batholith withinthe Tibesti Massif in southern Libya indicatean age of approximately 550 m.y. with aninitial Sr8?/Sr86 ratio of 0.706. Absence ofmetamorphic textures and structures make itunlikely that these rocks were rcmobilizedduring a Pan-African event. Even ifremobilization had occurred, it is unlikelythat the original rocks were older than 650m.y.

The only known ages of >2000 m.y. innortheastern Africa arc for samples from

32

Jcbel Owcynat. Published (Schiirmann,1974) Rb-Sr model ages on whole-rocksamples generally are 600 to 500 m.y. -old.Since the Sr isotopic composition ofwhole-rock samples would not be expectedto change as a result of metamorphism, thesedates probably are fairly close to the time ofigneous crystallization.

The isotopic data available indicate thatthe granitic rocks of northeastern Africawere produced 600 to 150 m.y. ago from alow Rb/Sr (probably non-sialic) source. TheJebel Oweynat area may simply represent acratonic fragment.

Comparative study of quaternary andactual lagoons populations of Cardiumglaucum (Mollusca, Bivalvia) aroundMediterranean Basin

Gaillard Jean M.

Cardium glaucum (Mollusca, Bivalvia)appears in Mediterranean localities as anextremely variable species. In fact somemorphological characters are dependent to amarked extent on the environment. Suchcharacters arc, to a high level, interesting incomparative paleoecological studies. Thelarge populations of quaternary Cardiumglaucum of paleoscdiments of lakes inFezzan can be comparatively studied withpopulations of the same species living inactual laggons along french mediterraneanseashores.

Hydrogeology and water resources ofthe Benghazi plain. Part II: Ground waterhydraulics

A. K. Ghosh

The flow conditions in the Benghazi plainaquifer are extremely complex. Not only themedium is highly anisotropic andheterogenous but also, the nature of flowvaries from laminar to turbulent. Theseconditions pose serious limitation on the useof standard techniques of estimating thehydraulic parameters like transmissibility,storage coefficient etc. In the present paperaquifer characteristics have been evaluatedboth by standard methods and also, by usingdata on water level fluotuation due tobarometric pressure and ocean tides.

In the Benghazi Plain transmissibilityvaries from very low (i.e. areas with no yield)to very high (i.e. karstic channels). The

present study reveals that the aquifer in theBenghazi plain area is neither completelyintergranular type it is completely dominatedby the presence of karstic channels. Boththese phenomena (i.e. intergranular natureand preferential channels) have their roles toplay in shaping the flow regime of theaquifer. The flow condition is essentiallylaminar in the intergranular part and itbecomes turbulent in the karstic channels.Further studies have been suggested in thepresent paper to examine the relativeimportance of the intergranular part and thechannels and their interrelationship.

These studies should include establishmentof separate piezometric network in theintergranular part and in the channels. Also,dye tracing should be performed to establishthe nature and extent of karstic channelspresent in the area.

Potassium argon, Rubidium Stronitiumages from the Tibesti Massif, S.P.L.A.J.

M. A. Ghuma

Potassium Argon and Rubidium Strontiumages (pairs) were done on biotits separatesand whole rock samples in the Ben Ghnemabatholith. The age pairs indicate animplacement age of 550 M.y. The K/Ar agesdone on biotite separates; and whole rockconform to an early Cabrian/late Protero/.oicage. The Ages range from 586 ± 23 M.y. toa low of 485 + 20 M.y. for the grandiorite,adamellite, granite and pegmatite,grapnophyr, ablite dikes. The granitic rocksyeilded 500 t 514 M.y. The adamelliteyielded a slightly higher K/Ar age at centerof batholight. The oldest K/Ar age werefound in the grandioritic rock to the east andextended to the southeast, of the hatholith.The gabbroic rocks yielded extremely lowK/Ar age.

The Rb/Sr age pairs for the granite andadamellites yielded the age 550 ± 11 M.v.The granodiorites and gabbro yield anisochron age of 556 ± 7. The adamellitesand granodiorite on the eastern part of thebatholith yielded an isochron age of 586 ±27. The initial ratio Sr8?/Sr86 for these suitesof the Ben Chnema batholith are lowconfirming the meniralogical finding that theBen Ghnema granitic batholith has evolvedfrom the lower crust-upper mantle sourceduring the Pan African event.

The K/Ar and Rb/Sr age in the Ben

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Ghnema batholith cover an age span of90-150 M.y. with an implacement age i-JOM.y. (early Cambrian/late Proterozoic). TheConcordence of K/Ar and Rb/Sr age withinlimits of experemental error further suggestthat the granitic rock of the Ben Ghnemabatholith and plutons further east in theTibesti massif are of primary magmaimplaced during the Pan African event inMiogeosynclinal environment to the west andeuogesynclinal environment to cast. The agesfrom the Tibisti massif conform with otherages further south done by Vachette (1964)in Chad and in the Sine basin done byWilliams (1968). The age pairs also conformwith other ages in North Africa as a whole,in the eastern Hoggar of Algeria (Ferra andGravelle, 1966) and southern Morroco(Hurley et Al., 1974).

The age relation in space and time indicatethat a whole region cast of Hoggar (includingthe Tibisti massif, the covered basement tonorth and east and regions west of JabalAwenat was formed during the earlyPaleozoic. The event 500-600 M.y. hadshaped the present configuration of NorthAfrican shield in the Jamahiriya, and most ofNorth Africa.

Pan African evolution in Jamahiriya andNorth Africa

Mohamed AH Ghuma & JohnJ. W.Rogers

In the Southern Jamahiriya and generalarea of North Africa a number of Plutonicigneous suites may be recognized ascalalkaline on the basis of published chemicalinformation. These suites are: the 550 M.y.old Ben Ghnema batholith of the Tibistis,Jamahirga (Ghuma & Rogers in press); the700 M.y. old batholithoc granite of Sudan(Neary et al., 1976) Some Pan Africanintrusive rocks near At Taif, Saudi Arabia(Marzouki & Fyfe, 1977) and 600-900 M.y.old plutonic rock associated with volcanicassembleges in South Western Saudi Arabia(Greenwood, et al., 1976). Petrographicdescriptions of other assembleges indicatethat calcalkaline plutonism was probablycommon throughout Archean to Pan-Africantime in Nigeria; in Archean to Kibaren timein the West African craton; in the 750 M.y.older granites of Egypt; and in lateProtorozoic time in Marocco, northwest ofthe West African craton. Adequate chemical

information on these petrographicallydescribed suites, however, is not available.Polarity has been demonstrated in the BenGhnema batholith and in the southwesternArabian shield Saudi Arabia.

The tentative impression obtained fromthe information summarized in the precedingparagraph is that the amount of calcalkalinemagnatism in North Africa decreased fromEarly Precambrian time. Much of themagmatic activity of the Late Proterozoic (toEarly Paleozoic) consisted of alkali-rich,silica-saturated granites that now extendfrom the western Ahoggar to the westernArabian shield. The full distribution and ageof these granites is not known, but it seemsa p p a r e n t t h a t t h e r a t i o ofalkali-granite/calcalkaline rocks has shown aprogressive increase from earlier to laterPrecambrian time in North Africa. It is notknown whether this increase has beengradual or episodic. :

Increase in the ratio of alkali granites tocalcalkaline rocks is probably related toprogressive increase in crustal stability inNorth Africa. At the present time there is noevidence that this crustal stabilization wascaused by, or even occurred at the same timeas, conventional plate-tectonics-styleorogenic activity. The segregation processmay, in fact, merely represent continuedsegregation of lithophilic elements upwardout of the mantle.

Structure-Libya

Gus H. Goudarzi

Libya situated on the Mediterraneanforeland of the African Shield, extends overa platform of cratonic basins. Severalorogenies affected the tableland and formedthe present major structural and tectonicfeatures. The recognized major diastrophicdisturbances include the Caledonian andHercynian orogenies in Paleozoic time, anddisturbances during Cretaceous, middleTertiary (Oligocene through Miocene), andHolocenc time. These events caused uplifts,subsidence, tilting, faulting, and instrusions.However, the effects of these diastrophicevents were generally broad, andcomprcssional lolds are very few. East- westand north-south trending faults are present,but the major fault systems trend parallel tothe Red Sea and other African rifts.

Precambrian basement rocks are exposed

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in south-central Libya, west of Jabal Eghei,Tibcsti area, in the southeastern part nearthe borders with Sudan and Egypet, at JabalFez/an north of Brach, and north of Waw anNamus.

Structure contours drawn on top of thePrecambrian basement in north-westernLibya trend generally east-west. From thecenter of the Hamada basin, the contoursshow a rise southeastward from 500 m belowmean sea level to 500 m above sea level.From this structural high, the basementplunges westward into Tunisia and eastwardinto the Sirte embayment in the eastern halfof Libya.

The major northwest-trending faults in theSirte embayment have large displacementsand suggest tension during formation. In thesouthern part of the embayment, the faultstrend nearly north. Structure contours showthat the top of the basement is at depths of1 "JOO m to more than 7000 m below sealevel. Contours of individual blocks suggesttilting to the north.

Structure contours drawn on top of thebasement on the Cyrenaica platform innortheast Libya show that the basement risesfrom more than 5000 m below sea level onthe Egyptian border to the east and on theGulf of Sirte to the west to 3000 m below sealevel along a north-northwest trending archthat has several structurally high areas. Anarcuate fault of probable Tertiary ageseparates the Cyrenaica platform from thegenerally depressed Sirte embayment to thewest and southwest and from theMediterranean basin to the north. Thestructurally elevated area of the Cyrenaicaplatform and the north end of the Hamadabasin in western Libya may have beenconnected by the now technically depressedGulf of Sirte.

In the southern part of Libya, thebasement rocks probably are as much as1700 m below sea level in the Kufra basin(southeastern Libya) and as much as 3000 mbelow sea level in the Murzuk(Morzuq-Marzuk) basin (southwesternLibya).

Study of the Karstic Spring of AynZayanan

A. Guerre

Ayn Zayanah, the largest spring in theJamahiriya, is located in the northern part of

Benghazi Plain at 1.5 km inland from theshore line. It flows into a natural basin opento the sea. The Blue Lagoon. The springrepresents the outlet of an aquifer complexmade of tertiary limestones and draining agroundwater basin of nearly 4200 km2,extending over the northwestern slope of theJabal Akhdar range. Its well regulateddischarge was 5.5 mVsec in 1977 of brackishwater T.D.S. averaging 16.5 g/1.

Important karstic features occur mainly inthe downstream sector of the basin andparticularly in Benghazi Plain whereessentially fossil karstic features and activegalleries are well developed. The remainingpart of the basin is constituded of amicrofissured-microporous limestone aquiferof rather low permeability.

The karstic system immediately upstreamthe spring, in Coeffiah area, is characterizedby two superimposed gallery networks atdepths -10/-20 and -90 m. b.s.l. connectedwith a few large diameter vertical pipes.Detailed investigations of this active karstand of the surrounding limestone media havebeen carried out by various means: divingexplora t ion , geophysical surveys(electromagnetic, electrical soundings,microgravimetry, shallow seismic refraction)and core wells with permability tests.

Regular measurements of discharge, waterlevel, salinity and water temperature havebeen performed on an observation networkcompleted by 7 access wells drilled on themain flowing galleries.

The analysis of the data has permitted tostudy the hydraulic behaviour of the karsticsystem under different natural water levelconditions and to define an optimal waterlevel elevation which is expected to preventthe sea water intrusion in the karsticnetwork. Technical alternatives to establishartificially this water level have beenenvisaged.

Large-scale fossil land-slides at theMessak Mellet/Plateau du Mangueniescarpment

Jorg Grunert

Geological profiles along the MessakMellet/Mangueni escarpment are difficult toobtain, because the in-situ parts of thefrontslopes are largely obscured by largelandslides. In the north of the study area therotated slide segments are often more than 1

km long and more than 100 m wide. Theyare easily mistaken for tectonic features. Thelandslides cover as much as 3 km of terrainin the foreland, as measured from theplateau rim.

Landslides in the south of the study areaarc somewhat different in aspect, more of agiant mudflow type with more pronouncedantithetic dislocations along the plateau rim.Landslides also form the slopes of thenorth-south trending tributary valleysentering Enneri Achelouma from both sides.

Landslides are the outcome of a fortuitouscombination of lithology, erosional history,and climatic history. They occur whereverred triassic clays and/or carboniferous marlsunderlie the Nubian sandstones. Landslidingbegan after erosion had changed theescarpment's front slope profile from a•relatively gentle, stable, and sigmoidal shapeto an overstcepened profile" likely to besimilar to those sections of the escarpmenttoday which are not underllain by clays. Thelowermost piedmont plain (or "pediment")was already dissected down below thepresent wadi bed level when sliding began.The landslides cover remnants of the lowestand of more elevated former surfaces.

Evidently climate was less moist thanduring the time of piedmont plain formationunder humid subtropical conditions, but stillmuch more humid than today, as the claysmust have been throughly wetted bygroundwater in order to permit landsliding totake place. The clays are completely drytoday.

All of the landslides are fossil and inactivetoday, as is evidenced by more than onegeneration of dune-sand covering in thecentral section of the research area, byseveral cycles of alluvial fan formation, glacisformation on soft materials, and subsequentdissection, all post-dating the landslides; andby the presentday erosional features of thelandslide areas. Small final dislocationsamong the landslide segments appear to havetaken place during the youngest majorpluvial.

Geological and geomorphologicalobservations on the north slope of theTibesti Mountains

Horst Hagedorn

The geology and geomorphology of thenorth slope of the Tibesti Mts. have been the

subject of only a few studies. In the presentpaper some results of stratigraphic andgeomorphic field work in the lower Yebigu6Valley and the Tibesti foreland are putforward, based on field work during repeatedstays at the German Research Station atBardai and on aerial photographinterpretation.

Emphasis is given to the structure andaspects of the sandstone cover, themetamorphic basement (Tibesti€n) and tothe younger volcanic features. Graniteintrusion NE of Aozou, which are ofimportance for both the stratigraphicsubdivision of the basement and for thegeomorphic development of the region, areanalyzed and classified by their highlyvarying appearance in the field.

Drainage and tectonic patterns arcanalyzed for selected areas and parametersderived for an overview classification.

Studies on present-day gromorphicprocesses in the arid northern margin of theTibesti Mts. show that eolian deflation,corrasion, and accumulation are dominanttoday. For the Holocene and Pleistoceneperiods there appears a sequence of periodsof dominant fluvial and eolian activity,expressed in a repeated pattern of changingaltitudinal zones of landform developmentwithin the mountains and their foreland.Radiocarbon dates indicate the final twohumid periods of the Holocene around 10 -7.000 y.b.p. and i.000 y.b.p.

Finally an attempt is made to apply theresults of morphodynamic studies to thesolution of geodynamic processes.

The Tertiary Volcanic rocks of Libya andchad - Their plate Tectonic significancefrom Paleomagnetic andPotassium-Argon age information

J. M. Hall, P. H. Reynolds andI. L. Gibson

We present extensive basic data withwhich to test conflicting models for theabsolute motion of the African Plate. Thetest proposed is to examine the absolute agesequence and paleomagnetic poles for theapproximately north-south line of Tertiaryvolcanic areas extending from Tibesti inChad through Jebel Eghei, Haruj Assuad andJebel Soda to Garian in Libya. Common polepositions, corresponding to the geographicallocation of one end of the line, or a regular

36

progression of ages along the line, would beevidence for a Hawaiian type motion of alithospheric plate over a fixed mantle thermalanomaly (a "plume" or "hotspot"). Detailedpaleomagnetic evidence is available for thethree northern areas while 27 generally welldefined potassium-argon whole rock ages aredistributed between all five volcanic areas.With one exception the ages are Neogene. Asignificant and almost certainty realoverlapping spread of ages of from 6 to 14my characterize all areas except for JebelSoda. This fact, together with the spread ofpaleomagnetic pole positions, mitigatesagainst a simple Hawaiian type ofplate-mantle relative motion. Possiblecomplicating factors such as the presence ofcontinental crust and the sampling bias infavour of late, capping volcanic products areconsidered. However, in the absence offurther information, it seems necessary toregard the Tibesti-Garian volcanic line asbeing the product of several discrete mantlethermal sources. As'such, the centers do notprovide clear information on the recentabsolute motion of the African Plate.

Early Cenozoic Calcareousnannoplankton Biostratigraph andPaleobiogeography of North Africa andthe Middle East and Trans-TethyanCorrelations

Bilal U. Haq and Marie-Pierre AubryIn the Early Cenozoic, North Africa and

the Middle East formed important parts ofthe Tethyan link between the Atlantic Oceanon one side and the western Pacific Oceanon the other. The epicontinental marinePalcocene-Eocene sections of this region areindispensible in the understanding ofcalcareous plankton biogeographic patternson both regional (Tethyan) and worl-widebasis. In this paper we present calcareousnannoplankton biostratigraphy of thePalcocene-Eocene from Wadi al Atrun andPyramid Peak sections in northernCyrcnaica, N.E. Libya; Djebel Cherahil,Djebel Bou Dabbous and El-Kef sections inTunisia; Jebel-um-Rejam section in Jordan;Cherkessk and Essentuki sections in theCaucasus Mountains, U.S.S.R., and the JebelJenine sections in Lebanon. Correlations ofPaleocene Eocene strata in thetrans-Tethyan region (North Africa,including Egypt, and the Middle East,including Iran and Pakistan) based on

nannofossil and planktonic foraminiferalbiostratigraphy, are suggested.

A comparison of the Paleocene-HarlyEocene biogeographic patterns of theAtlantic Ocean with well preservedassemblages of the trans-Tethyan regionshow that the consituents of the open-oceanwere essentially similar to those found in theTethys seaway, with temporal differences inthe relative dominance of some taxa in thelate Paleocene. One relatively coldassemblage (Prinsius martinii ) persists for alonger time in the Central Tethys, than itdoes in similar latitudes of the Atlantic. TheDSDP sites in the Bay of Biscay show anannoflora that is essentially Tethyan incharacter.

Light micrographs of some less well knowntaxa and scanning electron micrographs ofwell preserved assemblages are illustrated.Three new species are described:Fasciculithus aubertae, F. stonehengeni andHeliolithus floris.

Tectonics and rock stress in theJefren-Azizia area/Tripolitania/Libya

Helmut Hausler

Investigations of the tectonic inventary andthe Recent rock stress have been carried outin the area between Azizia and Jefren during1976 and 1977. It was intended to deliniatethe tectonic behavior of rocks through time(Lower Traissic to Recent).

The field work included measurements offaults, folds, dikes, joints, stylolites,horizontal slickonsides and a new techniqueof receiving in situ stress data by overcoring.

The data reveal that different tectonicregimes were operative from the Triassic topresent times. During the Triassic there isevidence of a stress field with a NW - SE -oriented main compressivc stress, changingto a E - W - direction in the Jurassic. TheNW - SE - direction was rejuvenated duringend of Paleogene and Neogene as revealedby basaltic dikes, normal faults, joints andhorizontal stylolites.

In situ strain determinations have beencarried out at 12 sites. The horizontalstresses are predominantly compressive anddepict two orientations of horizontal maincompressive stress, NW - SE and NE - SW,the latter direction of which dominates in theeastern part of the investigated area.

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A preliminary Revision of the Sahabiformation

Jean de Heinzolin

The definition of the Sahabi Formationwhich is proposed here relies on twentymeasured sections located between 6 kmsouth of the old fort and 25 km to the N-N-Ealong the Sebket El Janain; accessibleoutcrops extend further north and east, notmeasured yet.

A total thickness of 79 to 81 m is recordedat P12 - P13, resting on the eroded anddecalcified surface of a bioclastic limestone,likely of Middle Miocene age.

The Sahabi Formation can be divided into10 recognisable Members and Submembersqualified P,Q,R,S,T,Ui,U2,Vi,V2 and Z.

Members P and Q are shallow marine tolittoral deposits. Members R to Y arccomplex estuarine deposits (mudflats,lagoons, diatomitic pools, fluviatile and tidalchannels) interrupted by two minor marineingrcssions; Member Z is a complex ofpalcosol horizons.

Both marine ingressions of Members Rand T are characterized by peculiarassemblages of molluscs and ostracods.

Vertebrate fossils are distributed at variouslevels from Member Q to Submember Vi;the richest concentrations in mammal bonesare found in the top of Member Q. inMember T and in Member LJ.

Profiles situated north of PI2 - PI3 showincreasing thicknesses of Members T and U,likely due to a monoclinal flexure.

Contributions to the Stratigraphy andMicropaleontology of Jabal al Akhdar,North Eastern Libyan Jamahiriya:3. Ostracoda and Planktonicforaminifera from the upper eocene ofJabal al Akhdar

F. Helmdach and R. El Khoudary

This paper presents the results ofmicrobiostratigraohic studies on the UpperEocene Apollonia formation exposed in thearea of Wadi Bakiir, N.W. Jabal al Akhdar.19 species (subspecies) of Ostracoda and 21species (subspecies) of planktonicForaminifera are discussed and illustratedand comments to their stratigraphic valueand geographic distribution are given.

Based on the recorded planktonicForaminifera the studied Upper Eocene

sequence is subdivided into a lowerGlobigerinatheka semiinvoluta Zone and anupper Globorotalia cerroazulensis s.l. Zone(Bolli, 1972).

Regional Hydrogeological aspects ofthe main artesian basins in North Africa

Himida, I. H. and Diab, M. S.

Regional geological structure of the NorthAfrican Desert Platform with considerationof the hydrogeological, hydrological andhydrogcochemical data in different regionsproved the existence of a number ofextensive complex multi-layered artesianbasins in which the Nubian Series formationsand Intercalary Continental formationsinclude the main ground water aquifers. Thepresent study reveals great similarities in thehydrogeological conditions and groundwaterchemical and genetic types for these artesianbasins. The hydrogeological conditions arecontrolled by the geologic structure and thepalaeohydrogeolical history of the artesianbasins in addition to the present arid climaticcondition.

The Quaternary Gargarech Limestone,Tripolitania: Geology, Sedimentologyand possible industrial utilization

Miloje Rich and Werner Smykatz-Kloss

The Quaternary Gargaresh limestone ofTripolitania makes an outstanding ridgealong the Mediterranean coast extendingfrom Zuara to Garabulli. The limestone ispredominantly built up of shell fragmentsand quartz sand. The present paper dealswith detailed micropaleontological,sedimentological. mineralogical andgeochemical analysis, including thedetermination of some characteristic traceelements. On the base of these investigationsand of some rock mechanical analyses theindustrial utilization of the Gargareschlimestone is discussed, e.g. its utilization forthe production of cement, as building stoneand for the production of hydraulic lime.

Current fluvio-geomorphologicalprocesses in the area of Djebel es Soda

Dieter Jdkel

The Djebel es Soda area lies 29°N on thesouthwestern edge of the Hon trench. In itshighest parts it reaches an altitude of 800 to

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900 m above sea level and is about 350 kmair distance from the Mediterranean (Syrte).Rainfall occurs mainly in the winter monthsand is therefore caused by Mediterraneancyclones. There are not enoughmeteorological measuring stationsdistribution over the area. For the most partwe must therefore rely on indirect climaticevidence such as fluvial formation processes.Studies carried out in the autumn of 1977showed that the northern parts of themountains receive higher rainfall than thesouthern edges. Fluvial forms thus showpronunced divergence characteristics.Observations and measurements revealedthat current precipitation very quickly turnsinto surface run-off. Seepage hardly occurson the slopes and on the basalt plateaus; it ismostly found in the wadis, where, as a result,groundwatcr renewal is possible. Because ofthe weathering process on the slopes thewadis contain a large amount of gravel. Thesize of the accumulated material and itsdistribution indicate that the intensity ofcurrent fluvial processes is at times equal tothat of older, pluvial, periods. Only theextent of fluvial influence was greater inpluvial periods than today, as fossilpediments, alluvial fans and terraces show.Karst phenomena are at present hardlyrelevant. Compared with other desert areas,fluvial forms in the Djebcl es Soda show noimportant differences and may thus beregarded as exemplary.

Groundwater Evaluation in WadiZam-Zam

Omar A. Jarroud

Agricultural development throughirrigation is a major effort in Libya. One ofthe areas being developed is the WadiZam-Zam. The Wadi Zam-Zam WaterSupply is entirely groundwater withessentially no local recharge. The mainsupply aquifer is artisian with pressure headof 65 m., above land surface.

In order to maintain sufficeint pressure tokeep a constant supply, the number of wellsand discarghe must be limited. Othergroundwater aquifers may be developed tosupply an additional resources to fulfilagriculture needs.

Water quality analysis indicates thatcorrosion should not be a problem other thanperhaps steady corrosion when the wells are

closed. Consider the total dissolving solidsand other criteria, water quality can beclassified as good for irrigation.

Groundwater cooling in Wadi Zam ZamArtisian Aquifer

Omar A. Jarroud

The artisian groundwater aquifer in WadiZam Zam has average temperature of S6°C.The water nust be cooled before applicationto agriculture.

Water temperature can be lowered bycooling pond or cooling tower orcombination of both in what so called spraypond. Unlined cooling pond is less expensivethan cooling tower but; requires higher waterconsumption. Therefore based on designassumption a mechanical drought tower mayconsidered more efficient than cooling pond.

Igneous rocks of the Jabal al Hasawnah

L. Jurdk, F. Fediuk and J. Sindeldf

This paper is review of new datas obtainedduring the geological mapping organized byIRC in the area Southwest of Al Jufrah.

Igneous rocks of three types and agesoutcrop in the Jabal al Hassawnah Mts.which in the central part of Libya andcentered 140 km NW of Sebha. The oldestare represented by granites andaccompanying aplites and pegmatites whichoutcrop mainly in two inliers of the total areaof 15 km2. On means of radiometry we haveobtained the values of 542 m.y. and 521 m.y.so that their intrusions can be attributed tothe Panafric Orogeny. The second groupwhich is present only very rarely is composedof rhyolite tuffes and tuffites in clasticsediments of the Upper CambrianHassawnah Formation.

The most interesting of all is the thirdgroup represented by young, phonolitc rocks.The alkali basalt-pholite association is verytypical for the Tertiary to Quaternarycomplexes of Libja. It has been examined indetail namely in the Gharian area (Piccoli1970, Almond et al. 1974). It is present, innone the less typical development and oneven a greater area, in the central part ofLibya where abundant phonolitic rocks ofthe Jabal al Hassawnah Mts. areaccompanied by a small amount of basalticrocks.

The phonolites are represented by

39

individual, isolated bodies whose number(regardless to a great amount of small dikes)totals 400 approximately. The bodies are notdisseminated randomly but follow the maintectonical plan of the underlying rock units.Outcropping in anticlinal elevantions, theyusually occur in the form of two concentricrings out of which the inner one is composedof a number of smaller bodies while not veryfrequent but dimensionally big bodiescomprise the outer one. The structur isemphasized by a vein rocks whose quantityincreases toward the centre. The innerstructure of the bodies is concentric as well,being made more significant by weatheringand selective erosion processes which afflictcentral parts of the bodies in a moreintensive manner, resulting in crater-likemorphology.

From the composition viewpoint, theaverage representative of local phonolitcs isa strongly alkali, unsaturated rock,corresponding to nepheline phonolite of20% normative nepheline and of 10% colourindex. The alkali sum reaches up to 15,7%while the most frequent value of the Na2O:K2O ratio is about 5:3. Possesing the agpaiticcoefficeint of 0,99±0,5, the rocks into aboundary zone between agpaitic andmiascitic phonolites. Out of 29 sampleswhich were analyzed, only one is slightlyquartz-normative. The types containingeudialyte are very remarkable, theirexistence was proven no later than in 19SSny P. Bordet et al. on the basis of peopleoccurences but there have been foundprimary outcrops recently. The amount ofeudialyte reaches occasionally up to 10%resulting in the increase of both the rocksnatural radioactivity and the rare earth'scontent.

The phonolite bodies are seldomaccompanied by subvolcanic forms ofplutonic appearance. The most remarkableof them, penetrating the Wadf DarmanGranite, has been differentiated fromessexite to nepheline syenite and its basictypes possess a distinguished aphinity toalkali basalts. The basaltic rocks of theinvestigated area are composed either ofveins or of lava flows and volcanic cones.Two phonolite samples were testedradiometrically, with the results of 15,7 and29,9 m.y. respectively. This value isconsiderably lower than that for the Gharianphonolites (Piccoli 1970). The relation to

flood basalts, bordering in the northwest, hasnot been determined by field morphology;however, radiometric data suggest a veryclose interval. There where phonolites andbasalt dikes are in contact the latter areyounger doubtlessly; phonolitic xenolites ofthe basalt dikes are easily susceptible tovitrification, due to the high alkali content.

Seismicity and Seismotectonics of Libya

R.M. Kebeasy & Y.H. Ibrahim

Data of earthquakes which occurred in andaround Libya during the period from year262 to 1977 were collected from localsources, National Earthquake Informationservice center and Bureau CentralInternational de Seismologie. Earthquakeparameters are listed up in chronologicalorder with description of earthquake effectswhenever it is available. The distribution ofepincenter indicated that most ofearthquakes take place along the coastalregion with the exception of few earthquakeswhich occur inland. Closs coincidencebetween epincenter distribution and surfacestructure could be seen. Time distributionshows rapid increase of earthquakeoccurrence. Depth distribution of earthquakefoci indicate that the siesmic plane is dippingtoward north. The relationship between thefrequency of earthquake occurrences andmagnitude is studied and accordinglyparameters of reoccurrency arc devised.Depending on the energy relessed duringearthquakes the region was divided intodifferent seismic zones.

Hydrogeology and Water Resources ofthe Benghazi Plain Part 1:Hydrogeological Set Up

Mohammed Yar Khan

The study area lies between 32° 15' and31° 58' N latitudes and is bounded on thewest by the Mediterranean sea and on theeast by the First Escarpment of the Jabal AlAkhdar.

Surface rocks of the plain are of MiddleMiocene age and are represented by theBenghazi Member of the Ar RajmahFormation; scattered Quaternary sedimentsoverlie the Miocene rocks and are mostlypresent along the sea coast. The Miocenerocks arc free of plications in the study areaand generally lie flat. Fractures and faultsoccur with significant north-south or

40

northwest-southeast trends. A north-southtrending prominent fracture system lies alongAr Rajmah Project-Beninah-Sidi Mansurline.

The limestones of the Benghazi Memberconstitute the main aquifer and arc underlainby grayish green marls and clays of LowerMiocene to Oligocene age. The Eoceneaquifer is mainly constituted of fossiliferousand dolomitic limestones. The lithologiccharacteristics of the aquifers frequentlychange due to fades changes and therefore atplaces only one aquifer occurs irrespective ofthe age of the sediments or there are morethan two aquifers.

The permeability of the aquifers variesfrom place to place and is mainly fromsolution along fracture and fault zones,although, there is also some primarypermeability in the calcarenitic and chalkytypes of limestones.

The groundwater quality deteriorates withdepth as well as from the east to the west.The phenomenon of salt water encroachmentwhich is a major adverse factor in thedevelopment of the water resources of theplain is also described and discussed.

Contributions to the Stratigraphy andMicropaleontology of Jabal al Akhdar,North Eastern Libyan Jamahiriya:4. Planktonic Foraminifera from themiddle Eocene of the NorthernEscarpment of Jabal al Akhdar

Riyad Hassan el Khoudary

The micropaleontological analysis ofsamples collected from the limestones of theApollonia formation exposed on thenorthern escarpment of Jabal al Akhdar, tothe south of Al-Hilal village, yielded besidean abundant benthonic foraminiferalassemblage, the following planktonic species:

Hantkenina cf. aragonensis, H. dumblei, H.mexicana, H. longispina; Globigerinathekasubconglobata subconglobata, Ga.subconglobata curryi, Ga. subconglobataeuganea, Ga. mexicana mexicana, Ga.mexicana barri, Ga. mexicana kugleri, Ga.index tropicalis; Orbulinoides beckmanni;Globigerinita pera, Gt. unicava unicava, Gt.unicava primitiva, Gt. africana, Gt. dissimilisdissimilis; Globigerina turgida, G. senni, G.yeguaensis, G. linaperta, G. trilobata, G.eocaena, G. cryptomphala G. hagni, G.pseudoeocaena pseudoeocaena, G. tripartita

tripartita, G. tripartita tapuriensis, G.baconica, G. venezuelana, G. gortaniipraeturritillina, G. pseudoampliaperlura;Globorotalia broedermanni, Gr. spinulosa,Gr. spinuloinflata, Gr. bulbrooki, Gr. lehneri,Gr. bolivariana, Gr. cerroazulensis frontosa,Gr. cer. possagnoensis, Gr. cer. pomeroli, Gr.cer. cerroazulensis; Truncorotaloidescollactea, Tr. topilensis, Tr. libyaensis, Tr.rohri, Tr. haynesi; Globigerinoides higginsi,and Globigerinoides sp. I.

The above mentioned planktonic faunas,which indicative for the Middle Eocene arcdiscussed and illustrated, and their worldwide stratigraphic value and distribution areindicated. A preliminary zonal subdivision ofthe Middle Eocene of Al-Hilal area is alsodiscussed.

Age and metamorphic evolution of thebasement complex around JebelUweinat

Jean Klerkx

The crystalline basement, outcroppingaround the alkaline intrusions of JebelUweinat, is composed at least by two majorlithological units. The distinction is based onboth lithological and metamorphiccharacters. The series of Karkur Murr,outcropping at the south of Jebel, consist ofcharnockitic gneisses, metamorphosed in thegranulite facies. Rb/Sr age determinations onwhole rock samples provide an age of 2670Ma.

To the North, and separated from theseries of Karkur Murr by a large zone ofmylonites, occur the series of Ain Dua: theyare composed granitic gneisses, with amineral assemblage characteristic of theamphibolite facies; these gneisses often areinjected by migmatites and locally they areaffected by granitization. The age of theanatectic granites is 1840 Ma. It is assumedthat the migmatitization is contemporaneouswith the anatexis, while the age of the mainmetamorphic event affecting the gneisses ofthe series of Ain Dua is uncertain; apreliminary interpretation suggests that theirage is close to 2700 Ma.

The major folds strike NNE and areoverturned to the North-West. In both seriesremnants of recumbent folds striking NS areobserved.

The relations between metamorphism anddeformation are discussed.

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The Transaharan Seaway during theUppermost Cretaceous

Cornelius A. Kogbe

There is obviously no controversy over theexistence of inland seas across the Saharaduring the Cretaceous. The Saharan seaswere ex tens ions of the Tethys(Mediterranean) sea and the South AtlanticOcean (Gulf of Guinea) into the AfricanContinent.

Geologists have, however, disagreed onpaleogeographic reconstructions of theseaway. Most workers agree in principle thatthere was an inland connection between theAtlantic and the Tethys through Libya,Algeria, Mali, Niger and Nigeria. Quitelately, one author stated categorically that noconnection existed between^ the SaharanSeaway and the Gulf of Guinea during theMaastrichtian and Paleocene. He reaffirmedthat there is no doubt that the Tethys sea hada connection with the Gulf of Guinea, butthat the connection was through the Atlantic.This conclusion was based on the distinctiveforaminifera assemblages in the coastalNigerian Basin and the Sokoto Basin.

Very recent discovery of the Maastrichtianammonite species Libycoceras afikpoensis(Reyment) in the Gilbedi area ofnorthwestern Nigeria definitely favours theexistence of a trans-Saharan seawayconnecting the Tethys and the Gulf ofGuinea. It can be erroneous to carry outpaleogeographic reconstructions simply onthe basis of foraminifera assemblage anddepth of sea water. Changes in sea waterdepths are meaningless to eurybathic.nectonic ammonites which can swim activelyin waters of different depths. The discoveryof Libycoceras afikpoensis in the SokotoBasin of north-western Nigeria reveals thepaleogeographic distribution of thisammonite in north and western Africa. Thegenus has been described from theMaastrichtian of Libya, Algeria, Mali, Niger.Southern Nigeria and Angola. The recentdiscovery in northwestern Nigeria confirmsthe connection between the areas listedabove and the Sokoto Basin during theUppermost Cretaceous.

It is significant to note that the genusLibycoceras (Hyatt) has also been describedfrom the Maastrichtian of Egypt, Palestineand Arabia. It is absent (or at least has neverbeen described) in the Atlantic coastal basins

of north-western Africa, including Morocco,Mauritania, Senegal and Ivory Coast. TheMaastrichtian connection between the Gulfof Guinea and the Mediterranean could onlyhave been across the Sahara.

Strain Measurements and the StructuralPattern of the Mesozoic and CenozoicWest of Horns, Tripolitania, NW-Libya

Karl-Heinrich Kraft

At 14 sites west of Horns in-situ strainmeasurements have been carried out, themost which are located in the UpperCretaceous Sidi as Sid Formation. Somerecent rock strain data are achieved of theMiddle Miocene Al Khums Formation andthe Quaternary Gargaresh Formation. Theresults obtained from the latter formationshow data that arc more consistent thanthose achieved from the older rocks.

7.") per cent of all strain data show aNE-SW direction of maximum horizontalcompressive stress ( Hmax). The horizontalstress recorded normal to Hmax is eitherslightly compressive or tensile.

Observations of small-scale tectonicalfeatures, such as joints, calcite filled veins,horizontal stylolites, slickensides, and minorfaults have been made to reconstruct thepalaeostress fields from Upper Triassic (AbuShaybah Formation) through recent times.

Considering all investigated structuralelements, it can be stated that the stressregime was not subjected to remarkablechanges between Upper Triassic andMiocene. The orientation of the mainhorizontal stress was NW-SE throughout thisperiod. A NE-SW-oriented extension existedtemporarily during the Upper Cretaceous.

In contrast to the areas in the west(Aziziah Fault) and in the southeast (HonGraben) there are no faults of majordisplacements in the investigated area of theEastern Jebel Nefusa. An influence by themain tectonic trends can be observed only bymeans of small-scale structural elements.

Sabkha sedimentary Environments andtheir relationship to mineral andHydrocarbon deposits

Jan Krason and J. Slade Dingman

Although the term, sabkha (literaltranscription in Latin letters) means inArabic the same as dry lake or salt flat in the

42

English language, recently, in the geologicalliterature, the Arabic word is morecommonly used. Therefore, authors of thispaper also use the term, sabkha, simply forcommunicative reasons.

The main purpose and emphasis of thispaper is for a better understanding of thosegeologic and geographic or paleogeographicenvironments which are characteristic forsabkha sedimentary basins and associatedmineral deposits.

In view of previous detailed fieldinvestigations of modern sabka environmentsby the senior author, supplemented by athorough study of up-to-date literaturerelevant to the subject discussed, it appearsthat sabkha sedimentary environments arecontrolled primarily by two specific factors:

1. Arid and/or semi-arid climaticconditions characterized by net evaporation;and

2. The presence of a sedimentary basinwhich is periodically flooded with water.

Besides these two factors, there are at leastseveral others which also control sabkhasedimentary environments, namely:sedimentological features, hydrogeologicalconditions, mineral composition and theirassociations, diagenesis and post-diageneticalterations, and sources of mineral and rockforming components. However, perhapsbecause of an improper understanding of allof these factors and/or a lack of appreciationof their complex interrelationship in mineralformation processes, some authors haveimproperly applied the sabkha sedimentaryenvironment as a metallogcnic model tosedimentary environments with seeminglypaleogeographic and lithofacies conditions,which in fact have been found not to becharacteristic of sebkha environments at all.

Nevertheless, upon consideration of all ofthe above mentioned factors, critical andrequired for metallic and non metallicformation processes, it is concluded thatsabkha environments can be favorable forvarious types of mineral and hydrocarbondeposits. In order to support this conclusion,examples of deposits which are known orthought to be associated with sabkaenvironments are given. Mallahat al Bariqah,located in the northwestern part of Libya, iscited as a classical coastal sabkha-type saltdeposit. As a result of a thoroughexamination (Krason and Wala, 1967), largereserves of sodium chloride and potassium

salts were determined.Special attention is also made to inland

sabkhas known as salars of the CentralAndes (northern Chile, western Bolivia, andnorthwestern Argentina) which are rich withcommercially valuable potassium and nitratesalts. One of the largest salars in the region,Salar de Atacama, contains as much as 2000to 4000 mg/1 of lithium in the brine(Erickscn, 1976).

In view of discussion and criticism of thosepapers referring to copper and uraniumdeposits considered to be associated withsabkha environments, the authors of thispaper conclude that sabkha sediments and/orenvironments should not be disregarded orunderestimated as favorable locations for theformation of valuable ore deposits. As anexample, the Yeelirrie uranium deposit ofWestern Australia is recognized as havingformed in an environment in which theclimatic, sedimentological, paleogeographic,hydrogeological and structural conditions areconsidered by the authors to be characteristicof an inland sabkha.

With regard to hydrocarbon deposits andtheir association with sabkha environments,references are made to Glennie's (1972) andLceder and Zeidan's (1977) publications. Inthe first case, the presence of paleosabkhaenvironments of the Lower Permian orRotHegendcs time in the southern part of theNorth Sea and probably some other partsof the Western European Permian basinis well supported (real also Richter-Bernburg, 1972). However, the authorsof this paper have considerable doubts inthe application of "Giant late Jurassicsabkhas of Arabian Tcthys" as proposedby Leedcr and Zeidan (1977). However,the presence of evaporites of sabkha originas caprocks to oil and/or gas reservoirs mightbe very meaningful, perhaps not only inthe Persian Gulf region, but in otherregions of the world as well.

In conclusion, the authors once againstrongly emphasize the importance ofstudying Recent Sabkha environments. Theresults of these studies along with a goodunderstanding of the role and interaction ofall critical factors required for mineral andhydrocarbon formation processes andpreservation conditions will ultimately leadto a better, more comprehensive approach toexploration for mineral and hydrocarbondeposits in the future.

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Pan African Plate Tectonics and itsRepercussions on the crust ofNortheast Africa

A. Kroner

Pan African belts of the Africanmainland and the Arabian-Nubian Shieldexhibit evolutionary features which are eithercompatible with intracontincntal ensialicdevelopment or with plate margin andWilson cycle tectonics during the time period-1100-500 Ma ago.

It is suggested that both the ensialic andplate margin developments were causedby the same fundamental subcrustal forcesthat are responsible for present-daylithospheric motion, and the PanAfrican event is therefore representativeof a transition from Precambrian ensialicplate tectonics to Phanerozoic Wilsoncycle tectonics.

The North African craton between thecentral Hoggar and eastern Egypt/Sudan ischaracterized by widespread late Pan Africanthermal activity, documented by voluminouscalc-alkaline granitoid intrusions includingalkaline and peralkaline ring complexes, aswell as a general resetting of mineral isotopicsystems in older basement rocks. Nagy et al.(1976) interpreted these features as evidencefor progressive eastward growth of the WestAfrican craton but I suggest that pre-PanAfrican continental crust including Archaeanelements (Ouweinat) was already inexistence in northeast Africa. This crustwas strongly affected by intraplatestresses resulting from closing of thePharusian ocean in the western Hoggarand collisional tectonics in the Arabianshield.

Much of the late Pan African deformationin northeast Africa appears to have occurredby struke slip motion and there is a strikinganalogy with the Cenozoic deformationpattern behind the Humalayan belt innortheast Asia.

Following the model of Molnar andTapponier (1975) the deformation patternsof Asia and northeast Africa are compared,and it is possible to relate the Pan Africanstructures and magmatism between theHoggar and Egypt/Sudan to continental.collision and indentation of a semi-infinitehot crustal segment by a cold rigid plate (theWest African craton).

Hydrogeology of the Gefara, N. W. Libya

G. P. Kruseman

This paper synthesizes the results of waterresources research in the Gefara plain,conducted or supervised since 1969 by theSecretariat of Dams and Water Resourcesand by the Council of AgriculturalDevelopment.

An outline of the different aquifers ispresented: the Ras Hamia sandstone aquifer,Abu Shaybah sandstone aquifer, Aziziyalimestone aquifer, Kiklah sandstone aquifer,the lower Miocene sandy limestone aquifer,the middle Miocene aquifer, and the aquiferof the upper Miocene — Pliocene —Quartenary complex.

The Gefara is divided into severalcompartments by NW-SE zones ofdisturbance. Each compartment has its owntypical aquifer configuration. They all havein common that along two East-West zonesof disturbance the older formations havebeen down faulted to deeper and deeperlevels. Several maps and cross-sectionsillustrate the depths, extension, andinterrelationships, between the aquifers. Thepaper concludes with remarks on theavailable water resources and theirexploitation.

The Sedimentation and Tectonics of theMurzuk Basin During the EarlyCretaceous

J. Lorenz

The late Jurassic to early CretaceousMessak Sandstone, cropping out in thenorthern part of the Murzuk Basin insouthwestern Libya, is one of the severallithologically similar formations, all formerlycategorized as "Nubian Sandstone", thathave recently been described and subdividedwithin the basin. These formations are partof a depositional system which derivedsediment from the uplifted Tibesti massif andthe Tibesti-Harouj anticline. This coarsesediment was transported north into andacross the slowly subsiding Murzuk Basin bya limited number of migrating braided riversystems in a humid climate. Principaldeposition occurred during flooding,producing broadly lenticular, tabularcross-bedded, coarse-grained sandstones. Atthe northern edge of the basin, the GargafArch created an elevated base level, which

44

ponded drainage in those parts of the basinthat were not areas of active streamdeposition, and were not being aggraded upto local base level. In these subsiding buttemporarily sediment-starved areas, largelakes and swamps collected massive claydeposits up to 20 meters thick. Nearer thesource, in the southeast, alluvial fan typedeposits compose most of the section.

Preserved thicknesses of this braidedstream and lake/swamp system do not exceed•500 meters in exposed sections, though theymay be thicker in the middle of the basin.The deposits are unconformably overlain bylate Cretaceous to Tertiary carbonates and/orrecent sand dunes. In the south and east ofthe basin, they unconformably overliePre-Cambrian to Paleozoic strata, while inthe west and probably north, they grade upout of the Tilemsin Formation, an undated,probably non-marine redbed sequence whichunconformably overlies Carboniferousmarine beds.

The Kaolin deposit of El-UweinaS,Fezzan

Werner Smykatz-Kloss. Khaled R. Mahmoudand Gilani Abdelgawad

During soil surveying in SW Fezzan a layerof light greyishblue, compact and somemeters thick claystone was detected aroundHl-Uweinat (Serdeles, 120 km N of Ghat).Mineralogically, the claystone consists mainlyof a well-ordered kaolinite- 1 T and ofquartz, with minor amounts of muscovite andgoethite. The latter forms small concretionsin the upper part of the claystone layer.From grain size analysis it is evident thatboth, the goethite (the concretions of whichare generally larger than 2 mm in diameter)and the quartz (which occurs mainly in thesilt + sand fraction), can be removed fromthe kaolinite material, thus enriching thekaolinite to a valuable raw material forseveral technological uses. The horizontalextension of this kaolin deposit is not yetexactly known, but below some soil profilesin Wad Tanezuft, W of the probable sourcerock, the claystone layer had been found,too. From mineralogical and geochemicalarguments it is evident that the kaolinite wasformed by weathering of the Silurian Acacussandstone and by transport to the northernplaya aroubd El-Uweinat.

The influence of local Geology and soilConditions on the Building responseduring earthquakes

D. V. Mallick & F. T. Morghem

Studies of damage to buildings duringeartquakes in seismically active areas haverevealed that the intensity of ground shakingduring earthquakes and the associateddamage to structures are greatly influencedby local geologic and soil conditions. Withthe result that it has become necessary totake into consideration the potential effectsof geologic and soil conditions in buildingdesign and in the zoning of local areas. Thispaper reviews the design provisionsfor estimating the effects of theseparameters, and suggests a correlationbetween the intensity of damage tobuildings during earthquakes and local soilconditions.

Geological Problems related toEmbankment dams in Libya

D. V. Malliok, Amin Awad,Siddik El Naas and Saad Khawalqa

This paper highlights the importance ofgeological and topographic characteristics ofthe site that have been considered as one ofthe governing factor in the planning, designand construction of various embankmentdams in Libya. The knowledge of faults,shear zones, the width and module of cracks,the depth of the weathered zones in theabutment and the corresponding type ofsoils, the dip and the strikes of the beddingplanes influences the alignment of the damaxis, the distribution of materials in the damand the inlination of the core. Methods oftreatment of certain defects such asweathering, faults, fracture, leakage,seepage and the control of ground waterrequire specific engineering measures likegrouting under pressure which will ensuresatisfactory foundations.

In addition, the engineering properties likedeformation moduls, compressive strength,creep, dynamic characteristics, damping,degree and the extent of rock weathering andthe influence of water on the rock behaviourare of primary importance in the dam design.

The foundation and the abutmenttreatment of Wadi Caam Dam project iscited as an example.

4-)

The Upper Cretaceous-TertiaryFormations of Northern Libya ASynthesis

Mohamed Megerisi & V. D. Mamgain

Voluminous information has beengathered for the past two decades on theUpper Cretaceous-Tertiary Formations ofNorthern Libya. Most of the information hasremained unpublished; Novertheless, the fewpublished papers and 1:2,000,000 scalegeological map of Libya has served as anucleus for the regional geological mappingon 1:250,000 scale initiated by the IndustrialResearch Centre in 1971. An area of nearly300,000 Sq. km has since been mapped inNorthern Libya and geological maps for1.69,000 Sq. km area have already beenreleased.

New data collected since the inception ofregional geological mapping has led to theestablishment of 22 mappable units for theUpper Cretaceous-Tertiary Formations ofthe Al Hammadah Al Hamrah-Al Jufrahregion and 19 mappable units for the AlJabal Al Akhdar region. The stratigraphicnomenclature of these Formations has beenrationalised and some of them have beenredefined in the light of new observations.

An attempt has been made here to presenta synthesised account of the stratigraphicstatus, ecological, Palaeogeographical, lithoand biostratigraphical nature of theFormations.

It has been observed that the UpperCretaceous Tertiary Formations of the AlHammadah Al Hamrah region exhibit aremarkable uniformity of characters andseem to c o n t i n u e b e l o w theNeogene-Quaternary cover to the east ofSine basin and can be favourably comparedand cor re la ted with the UpperCretaceous-Tertiary deposits of the westerndesert of Egypt and the Ghadames basin ofTunisia. The Upper Cretaceous-TertiaryFormations of Al Jabal Al Akhdar region,however, exhibit a fades distinct from the AlHamadah Al Hamrah region, reflecting, theirindependent tectonic histories.

A broad outline of the tectonic history ofthe area since the Upper Cretaceous timeshas also been presented.

The "Al Khowayamat Formation" anenigma in the stratigraphy of LibyaMohamed Megerisi & V. D. Mamgain

Some of the recently published geologicalmaps of Libya on l:2."5O,OOO scale show largeareas of the southern parts of Al Jabal AlAkhdar (Sheets NH 34-3,4 & 3.-5-1) exposingthe Al Khowayamat Formation; defined as a20 m thick sequence of dolomitic limestoneto dolostone forming the lower Membercapped by 6 m thick calcilutites andcalcarenites with reticulate Nummulitesconstituting the Upper Member (Mazaharand Issawi 1976).

The northern continuation of these rocksnorth of latitude 32°N had formerly beenmapped (Rohlich 1974) as Al MajahirFormation (Campanian) and Al FaidiyahFormation (Up. Oligocene-Lower Miocene)being the northern continuation of the Lowerand Upper Members of Al KhowayamatFormation. The Al Majahir Formation wasdated on the basic of unoriented thin sectionsof planktonic foraminifera, and the AlKhowayamat Formation was largelyconsidered as of Upper Eoccne-Oligocene inage on the controversial evidence of thepresence of a Nummulitic horizon at the baseof the Lower Member.

The controversy on the age wasaccentuated by the contrary claims andcontinued disagreement of the two teamssupported by their Micropalaeontologists.The difficulties of isolating the microfossilsfrom the hard dolostones and their poor stateof preservation coupled with the scanty andincomplete outcrop exposures in the fieldadded new dimensions to this problem; as aresult the objective facts as presented by thetwo teams were published in the geologicalmaps resulting in the disjuncted borders oftwo sheets.

Recently the Industrial Research Centrehas undertaken new investigations to solvethis problem and the results of these studiesare presented here.

Satellite Remote Sensing:The Other Alternativefor Reconnaissance Geologic Mappingin the Remote Partsof Southern Libya

Amin A. Missallati

Combination of Dotprints and coloredimages generation for single channels,multiple channels and ratios by digitalcomputer processing of LandSatMultiSpectral Scanner (MSS) tapes have

46

been used in this study to locate terrainfeatures and discriminate different rock typesin a test stitc area of approximately 900square kilometers.

This test site is a small part of a large arealocated in the northern parts of the Tibestiregion in southern Libya which waspreviously mapped by traditional fieldmethods.

The resulting Dotprints and coloredimages covering the test site area, depictgeologic patterns, closely resembling thosemapped by traditional field methode. Theyalso delineate more precisely some of thegeologic boundaries as well as new structuralpatterns.

High-Pressure Megacrysts in Basalticlavas from Djanet Oasis, EasternHoggar, Algerian Sahara

L. Morten - P. L. Rossi - M. Bondi andA. O. limn felt

Megacrysts of aluminous clinopyroxeneand olivinc are present in undersaturated(11.1 Ne-normative) basaltic lava flows fromDjanet, Algerian Sahara, Megacrysts ofspinel and orthopyroxene are found in thegravels on the surface of the lava flows. Theclinopyroxenes are rich in Ca-Tschermak'sand jadeite components and the olivines areFo-rich.

Mineral chemistry, compared withexperimental petrology data suggests thatthese megacrysts are near liquidus phases atabout 22..i Kbars and 1400°C of a picritfcnephelinite magma. Fractionation at highpressure of such a megacryst suite is inferredto be responsbile for the genesis of theundersaturated basanite host rock.

Is plate tectonics an Universal Theory?

Stanislaw Ostaficzuk

Some doubts to the plate tectonics havearisen in the domain of the BasementTectonics. Straight lineaments, crossingdifferent structures and/or regions arecommon on space imageries.

Author discusses some geologicalimplications of different kinds of lineamentsknown to him from Libya and Europe. Thecourse of these lineaments, supposedlyrunning under the mediterranean deniesrecent plate tectonics concepts about thetectonic history of this basin.

Late Quaternary of southern Libya,climatic history

Pachur, Hans-Joachim Paul

For the reconstruction of humid phases ofclimate evidence from flat areas is moreconclusive than evidence from mountainousareas, which have a more favourable climateowing to their orographic situation. For thisreason our investigations are concentrated onthe northern Tibesti foreland, the SerirTibesti and the Serir Calanscio, and the GilfKebir region. High-carbonate freshwatersediments and low-energy fluvial forms wereproved to exist in the Serir Tibesti.Stratigraphical investigations showed a triplestructure of the fluvial accumulation. Lakeformation took place in two humid phasesaround 13000 - 7000 B.P. and around 5000B.P. Interpretation of large mammal bones,chronological classification by means of 14Cdates and consideration of prehistoricevidence permit the reconstruction ofgeoecological conditions: aprecipitation ofapprox. 200 mm per annum is inferred. Rockfrom the Tibesti was transported fluvially ina probaly periodically water-bearing riversystem with a length of over 1000 km. It isassumed that the Tibesti Mountains drainedinto the Mediterranean Sea. Owing to thisriver system, the elephant was still able toexist in the Serir Calanscio around 3000 B.P.The lakes finally dried out around 1900 B.Pwith the growth of tamarisks on the lakefloor. Prior to this, sebkhas were formed,and, about 5000 B.P., a change inaccumulation occurred, shown by silt contentin the calcareous muds. A fundamentallysimilar climatic development also took placein the Tibesti Mountains. Silty-sandy playasediments were found in the Gilf Kebirregion at the foot of cuestas. Theiraccumulation was preceded by heavydeflation of the bedrock. Stratigraphicevidence suggests that these sedimentsbelong to the low-carbonate, siltysandystillwater deposits in the Gilf Kebir. The ageof the sediment base is about 8400 years.The top of the over 6 m thick outcropscontains temporary places of settlementdated at 3800 B.P.

There fluvial terrace systems exist in thevalleys of the Gilf Kebir.' A characteristicfeature is the damming up of the wadis bydunes, causing the formation of backwaterbasins. In recent times these basins were

47

hollowed out by the wind. In the Gilf Kcbirforeland — as in the Serir Tibesti — the windis the primary agent of morphologicalchange, dominating in the Gilf Kebir regionsince approx. 2800 B.P. and in the SerirTibesti since about 1900. The oldest datesfrom Libyan deserts are from high-carbonatelake sediments, dated at about 26000 B.P.,and from calcareous tufa, about 28800 B.P.The more recent humid phases in the SerirTibesti and Serir Calanscio are onlydocumented in the period around 8500 B.P.Both areas contain neolithic temporarysettlement places. These occur morefrequently, however, in the Serir Tibesti.Older sttlement phases were determined athigher altitudes in both areas. Investigationsto date show the Libyan Desert to beextremely arid, both during the humid phasesof the Holocene and at the present time.Further investigations are being carried outin the Gilf Kebir.

Water resources of the SocialistPeople's Libyan Arab Jamahiriya

P. Pallas

Although Libya has to be considered as anarid country with an average yearly rainfallof less than 100 mm over 93% of thecountry's land surface there are importantpotentialities for groundwater development;but, while most of the population, andconsequently the water demand, isconcentrated within a narrow strip along theMediterranean coast, most of thegroundwater potential is located to the southin the desert areas.

In this paper, five groundwater systems areconsidered as relatively independent fromeach other, so that even important abstrationfrom one groundwater system area will nothave any predictable effect on the othernearby systems: the Gefara Plain system —the Hamada el Hamra, Sawf el Jin basin,Misratah area system — the Marzuq basinsystem — the Sarir - Kufra system — theJabal Akhdar system.

Because of the rapid development of theirrigated agriculture mostly after 1969, thegroundwater extraction passed fromapproximately 600 - 700 million cubicmeters (Mm3) per year in 1969, to 1600MmVycar today. Within the next 10 yearsthis figure will reach 3700 MmVyear. Whilein 1969, most of the groundwater extracted

could be considred as a renewable resource(the water extracted was approximatelycompensated by the annual recharge of theaquifers), in 1977, 60% of the groundwateris taken from the storage and in future 80%of the groundwater will come from reserves.

Quaternary lacustrine deposits in theWad) Shati area, Libya

N. Petit-Maire, E. Bonifay and G. Delibriaswith the collaboration of S. Ghellali and A.Sbeta

Along 23° 30' N, between Al Mahrugahand Ashkida, extensive outcrops withlacustrine shells deposits (Cardium glaucum,Melania tuberculata) were found. A numberof lake stages probably covering the wholePleistocene period may be infered from thetype (shelly limestones or shelly sands) andsituation of fossiliferous beds and otherexposed sediments.

The Umm el Gadawal exposure, betweenthe highest coquinas and the present sebkalevel, is dated 22500 years B.P. This date fitsone of the high lake levels observed byServant in Tchad and Gasse in Ethiopia.

Recent quaternary lacustrine palustrinedeposits in western Libya

N. Petit-Maire and G. Delibrias

In the Derj (30° N) south of Ghadames(29° N) and Fdri (27° 30' N) regions, thickbeds with concretions after vegetation andlacustrine gypsum deposits mark the pastextent of fresh lacustrine/palustrine shallowwater areas.

Associated prehistoric sites indicate humansettlements around these water-places duringthe Upper Pleistocene (Aterian) and theHolocene (Neolithic). Charcoal fromfire-places are being isotopically studied andwill precise these dates when occidentalLibya was less arid than nowadays.

Libyan and Indo-Pacific faunas ofMolluscs: Tertiary to Recent

Giuliano Piccoli

The Tertiary mollusc faunas of Libya,known so far, are represented by pelecypodsand gastropods of the neritic environment;the sea extended far inside the countryduring the Paleocene, forming later the longgulf of Jofra. The faunal assemblages of

48

molluscs are similar to the Indo-Pacific onesin the Palcogene and the Miocene; in theuppermost Miocene the faunas change incomposition and since then the newinhabitants of the Mediterranean arc ofNorthern Atlantic origin. The facts abovelisted depend on the tectonic history of theMediterranean region as well as no theclimatic changes within the area during thelate Tertiary.

Hydrogelogy and Water Resources ofthe Benghazi Plain Part III: Hydrologyand Water Balance

T. S. Raju

The hydrological conditions of theBenghazi Plani and its adjacent areas andwater balance of the Benghazi Plain, arepresented.

The climate of the area is semi arid. Theaverage rainfall for the past 20 years variesfrom 141 mm at Saluq, south of theBenghazi city to 393 mm at Qasr Libya nearthe top of the Jabal Al Akhdar. During theperiod from 1930 to 1940 the rainfall wassomewhat higher. Potential evaporation forgrass covered areas varies from 1S30 mm atShahat on the Jabal Al Akhdar to 1715 mmat Beninah. Average annual rainfall surplusestimates based on daily water balance ofclimatic parameters vary from 18 mm atBenghazi to 8S mm at Al Marj. Averagerunoff coefficient for the Wadi Al Qattarahdrainage basin, which flows onto the plain isabout 3%.

Water balance of the Benghazi Plainindicates an average annual net recharge of141.2 million m3 from rainfall, surface waterand ground water inflows, production of 81.6m3 and outflow from the Ayn Zayanah of74.0 million m3 and that 14.4 million m1 iscoming from storage, indicating the overdraftcondition of the groundwater reservoir.

hstimates show that the majorgroundwater inflow to the study area takesplace through karstic channels and the flowthrough fractured and porous limestoneoutside the karstic channels is relativelysmall. However, the total groundwater inflowestimated base on transmissibility, hydraulicgradient etc (42.1 million m3 per year) isquite low when compared to thegroundwater inflow estimated through waterbalance which comes to 11 ")..•> million m3 peryear. This indicates the probability of

additional karstic channels entering the plainfrom the 1st Escarpment and more flowthrough them than indicated.

The Paleocene Trans-SaharanTransgression and its Ostracod Fauna

R. A. Reymerit & E. R. Reyment

During the Early Paleocene (Danian), orlatest Maastrichtian, the last of the extensivetrans-Saharan epicontinental transgressionsbegan. At its acme, in Late Paleocene time,the sea stretched from Nigeria in the Gulf ofGuinea, through present-day Niger Republic,Mali, Algeria and Libya. Faunistically, themost striking feature of this transgression isthe wide distribution of many species ofostracods; there are at least 24 West Africanspecies in the Paleocene of Libya. Anattempt is made to trace the course taken bythis long, narrow inland ocean and toreconstruct some of the ecoogical conditionsthat prevailed during the relatively briefperiod of its maximum extent. Mondiallyconsidered, this transgression is anamalousand it is suggested that it could have resultedfrom the effects of geoidal eustasy.

The Paleocene transgression is comparedand contrasted with the earlier analogues, towit, that of the Cenomanian-Turonianpassage and that of the Late Campanian toEarly Maastrichtian. Statistically basedpalaeobiogeographical comparisons betweenthe Libyan and Nigerian associations arepresented. It is demonstrated thatmultivariate clines seem to have existed forall species analyzed quantitatively, such thatthe more northerly associations of Libyahave tended to develop a greater carapacevolume than the equatorially centeredassociations.

Gravity-Tectonic trend analysis ofSiwa-Giaraboub Oases Area

S. Riad, Hassan A. El-Etr and Magdy A.Mohammed

The area studied lies between latitudes 29°N and 30 30° 30 N, and longitudes 24° E and26° 30 E. It includes Siwa area in theWestern Desert of Egypt and Giaraboubarea in the Eastern Desert of Libya. TheBounger anomalies in these areas wereinvestigated and used for determining faultsystems, probably present in the basement.Statistical studies of these faults show the

49

presence of three main tectonic trends: E-W,N 2">° E and N 60+ W.

In Siwa area these trends are all present,with almost the same importance. InGiaraboub area the E - W trend isprominent.

Shear zones of NE (L.L.) and NW (R.L)directions were detected in Siwa area.

The subsurface structure in both areas iscomplicated, but it is believed that the twooases are lying over uplifted blocks of thebasement. They are being complicated by thepresence of local positive and negativestructures and by the action of shearing too.

Uranium in Pan-African Belts

John J. W. Rogers

The Pan-African event of *>00-600 m.y.age is characterized, in different parts ofAfrica, by a variety of processes. Theseprocesses include crustal reactivation,anatexis, subduction, production of alkalirichgranites, and extensive displacement ofcrustal blocks. Most of the exposedcrystalline terrane, and probably thebasement, of Libya has been affected by oneor more of these processes. Regardless of thespecific process occuring in a particular belt,areas of Pan-African activity must beregarded as zones of extensive release ofenrgy. The extent of global energy release atthis time is shown by the widespreaddevelopment of Pan-African belts in Africaand the abundance of their correlatives inother parts of the world.

Major uranium deposits are associatedwith igneous activity in at least twoPan-African belts. The Rossing deposit ofN a m i b i a o c c u r s inpegmatite-alaskite—migmatite bodies in theDamaran belt, and broad areas of uraniummineralization are associated withemplacement of the Younger Granites ofEgypt. Furthermore, much of thehydrothermal mineralization in the Katanganbelt of southern Zaire is also of Pan-Africanage. Deposits of correlative age and andoccurrence elsewhere include mineralizedgneisses and granites of the SouthernAppalachians of the United States and theCurrais Novos area of Brazil. It seems likelythat the thermal energy release that occurredin Pan-African belts was associated withupward migration of uranium at that time,but exact relationships and mechanisms are

unclear. Pan-African belts, therefore, shouldbe considered likely areas for uraniumexploration, both in the crystalline rocks ofthe belts and in sediments derived by erosionof the belts.

Comparison between the lateQuaternary Terraces around the Atakorand Tibesti

P Rognon

The alluvial terraces of the large Atakor(central Hoggaar) and Tibesti wadi arecompared. They directy depend upon theclimatic variations of the Central Sahara inthe recent Quaternary.

In spite of a distinct lithology, theircharacters are alike. The Tibesti"Obcrterrasse" was formed during an aridphase close to the present period; its origin isrhexistasic; it is well represented in NWTibesti. It can be found widely around theAtakor where it developed down from thegranitic regions and is made of sand andreddish gravels.

In both regions, this terrace was then cutthrough. Then, grey or brown clayey silts,often rich in organic matter, constitute a newinterfingered terrace. They deposited, duringa biostasy phase, during a climatic periodwith rain all around the year and a quitedense vegetation.

This is the Tibesti "Mittelterrasse", dated1-5000 to 8000 B.P. Its relations with a wetmediterranean type climate have been shownthrough pollen palaeosoils and diatomsanalysis, as well in the Tibesti as in theAtakor. The Tibesti "Niederterrasse"developed during a drying up period(rhexistasy phase). It is mainly formed withsands, with flowing conditions close to thepresent ones. It is less developed in theAtakor where the granulometry is finer(silts) and where it is often confounded withthe "Mi t te l te r rasse" . It could bedistinguished from it and dated less than6000 BP, in some places.

It ssems that the process from the Pluvialperiod to the extant arid one was moreprogressive in the Atakor than in the Tibesti.

Tectonic Development of Jabal alAkhdar

P. Rohlich

Jabal al Akhdar and adjoining territories

•50

north of 32 degrees latitude have beensurveyed in the first phase of thecontemporary geological mapping of Libyaorganized by the I.R.C. Tripoli (Klcn, 1974;Rohlich, 1974; Zert, 1974). The presentpaper, being largely based on the results ofthat survey, deals with the questions of thetectonic development of Jabal al Akhdar.The essential conclusions may besummarized as follows.

1. Tectonic history: The sedimentary rocksexposed in Jabal al Akhdar (marine UpperCretaceous and Tertiary) were modertelyfolded and faulted during the Santonian andearly Ypresian intervals. From MiddleEocene to Middle Miocene, the area wassubject to a slight warping followed byoscillating transgressions of a shallow sea.The youngest tectonic movements resulted ina gentle doming of the area associated withdownfaulting of certain zones. The presentgross geomorphology of Jabal al Akhdarroughly corresponds to its final uparchingafter the Middle Miocene.

2. Structural systems: The principalstructural aligment of Jabal al Akhdar isNE-SW (late Cretaceous folding axes, majorfaults in the northwestern flank). Thissystems is crossed by NW-SE and E-Wtrending faults. More easterly, the E-Wtrending slight faluting is dominant. Someprominent faults were reactivated during thetectonic development, partly with movementinversion.

3. Geotectonic position: Jabal al Akhdardeveloped in a tectonically exposed marginalpart of the North African shelf. The UpperCretaceous and Eocene sediments of thepresent coastal area partly may have beendeposited on the continental slope. Jabal alAkhdar is the most prominent part of anextensive tectonic paleobarrier between theTertiary epicontinental basin of northeastLibya and the Tethys deep-sea basin.

Oligocene Echinoid Faunas fromDarnah, Libya, and TheirPalaeoenvironmental significance

E. P. F. Rose

Irregular echinoids are an importantelements of 'the macrofauna in Tertiarycarbonates which form the Jabal al Akhdarregion of northeast Libya. The echinoidfaunas are diverse. Specimens are locallyabundant and generally well preserved. At

least thirty species occur within theOligocene (Al Abraq Formation) nearDarnah. Six different lithofacies may bedistinguished in wadi exposures from Darnahto al Khalij twenty kilometres further east,each characterized by a distinctive echinoidbiofacies. From anlogy with livingclypeasteroid, cassiduloid, and spatangoidechinoids. and functional interpretation oftest morphology, this echinoid distributioncan be related to the animals' original modeand place of life. Additional palaeoecologicaldata are contributed by associated fish,molluscs and foraminifera. The differentshallow-water, marine environments thuscharacterized can be recognised more widelyin the Mediterranean Tertiary.

The type sections of the Creataccousand Paleocene of Tunisia proposed forthe Hypostratotypes and theirapplication for correlation withplanktonic zones of Libya

Joseph Salaj

Correlation of Tunisian type sections ofthe Upper Cretaceous and Paleocene,proposed for the Hypostratotypes, withstandard Upper Cretaceous and Paleoceneplanktonic zonation, applied in Libya.

The vertical distribution of planktonicindex species in the Upper Cretaceous ofTunisia on the one hand and plylogeneticrelationships of some species and genera ofthe families Globotruncanidae andHeterohelicidae on the other hand point tothe possibility of solution of somestratigraphic problems as well as to a moredetailed subdivision of the Upper Cretaceousand Paleocene in Libya.

A feature specific of the North African,mainly Atlas region, is the presence of theTotundina cretacea — Praeglobotruncanaimbricata Zone, also known from thestratotype of the Turonian in the overlier ofthe Rotalipora turonica Zone and in theunderlier of the Helvetoglobotruncanahelvetica Zone.

The one-keeled species Globotruncanaturona sigali /Reichel/ is always found in theupper part of the Helvetoglobotruncanahelvetica Zone and in the basal part of theMarginotruncana schneegansi Zone italready becomes extinct.

Appearance of the subspecies of thespecies Globotruncana concavata /Brotzen/

.•51

unambiguously determines the lowerboundary of the Coniacian, however, theyare insuitable for a detailed subdivision ofthe Coniacian-Santonian.

The Upper Coniacian-Santonian is verywell defined by the lineage of species of thegenera Sigalia and Vcntilabrella: Sigaliadeflaensis /Upper Coniacian/. Sigaliacarpatica /Lower Santonian/ Ventilabrelladecoratissima /Middle Santonian/Ventilabrella alpina /Upper Santonian/Ventilabrella glabrata /Lower Campanian/.

From the base of the Upper SantonianGlobotruncana fornicata manaurensis Zoneand proved also by ammonites in Tunisia, thespecies Globotruncana elevata elevata/Brotzen/ occurs first.

The Campanian as well as theCampanian-Maastrichtian boundary are verywell defined not enly in Tunisia /A.-L.Maamouri and J. Salaj 1971/, in the WestCarpathians /J. Salai and O. Samuel 1966/,mainly on the basis of the lineage:Globotruncana area area Globotruncana arearugosa Globotruncana falsostuarti.

The species Globotruncana falsostuartiunambiguously determines the Maastrichtianbase not only in the mentioned regions butalso at the stratotype of the Maastrichtianregions but also at the stratotype of theMaastrichtian /J.-P. Belicr and J.-M. Villain197")/. The Maastrichtian base in Libya hasso far been determined by appearance ofthe species Globotruncana conica, the indexspecies of the same zones /B.A.H. Eliagloubi1976/. The Upper Maastrichtian isc h a r a c t e r i z e d by t h e Z o n eRaccmiguembelina varians varians s.l.

To the Danian s.l,. on the contrary to theDanian s.s., arc assigned the zonesGlobigerina taurica — Globoconusadaubjergenis and the Turborotalia/Acarinina/ inconstans Sub/one, absent at thestratotype of the Danian.

For the reason that the T. /Acarinina/inconstans Subzone still belongs to thenannoplankton zone with Chiasmolithusdanicus, it is not considered as equivalent inage with the Globorotalia uncinata s.l. Zone.On the contrary, the latter together with theGloboconusa kozlowskii Zone alreadybelongs to the nannoplankton zoneEllipsolithus macellus. Both zones togetherwith the Globorotalia angulata Zone arcassigned to the Montian s.l.

The zones Globorotalia pusilla,

Planorotal ia pseudomenardi i andGloborotalia velascoenis are assigned to theUpper Palcoccne. It seems more correct tous to use the term Landenian s.l. /principle ofpriority/ instead of the term Thanetian. Thequalities of both stratotypes are essentiallythe same and not very suitable. In Africa theterm Landenian is rather used, also thesupporting profile for the Upper Paleocenc isproposed to be called Landenian s.l.

Stratigraphy of Al-Khums FormationNorthwestern Libya

Mostafa J. Salem, A. C. Spreng

Stratigraphy of Al-Khums Formation(Miocene) in the vicinity of Al-Khums,northwestern Libya is presented. Twentythree stratigraphic sections were preparedand studied in detail. Two members namelyRas Al-Mannubia Member (upper), andAn-Naggaza Member (lower) of Al-KhumsFormation are proposed.

This formation transgressively overlies thevarious Cretaceous beds with a prominantunconformity. A structure contour mapdrawn on the unconformity illustrates thepronounced releif developed prior to theencroachment of the Miocene sea. Thedeposition of Al-Khums Formation wasunder shallaw water conditions with reefpatches development near the formershoreline. Lithologic and paleontologicalcriteria indicate the formation represents twomajot transgressions separated by aregressive cycle.

In situ rock strain Measurements inLibya

Karlheinz Schafer

For the first time in situ rock strainmeasurements have been carried out inLibya. Except in Liberia there are noprevious in situ stress results of the Africancontinent north of the equator. In this paperI report the results of stress determinationsat 26 sites that extend from theTunisian-Libyan border to Derna/Cyrenaicain the north and to Ghadames and the Jufrahoasis in the south. The present rock strainhas been determined by overcoring of straingages that were bonded to the rock surfaces.The range of rock ages selected formeasurements was wide (Middle Triassic toQuaternary) but their lithologic character

was similar (solid homogeneous micrites).The orientations of maximum and minimumhorizontal stress revealed a consistencyacross large areas.

Most stress values vary from (MO bars,many range between "50 and 1 "50 bars and toone site the stress was tensile in all horizontaldirections. At least three crustal domains innorthern and central Libya can be defined bymeans of different in situ stress fields. Thewestern Libyan stress dovain extends fromTunisia into Libya and is terminated along aline that runs from Sabratah to Azizia, BuNgem and the Jebel Waddan east to the Hongraben.

This western Libyan stress field has aNW-SE-oriented maximum stress that ishorizontal and compressive. To the eastfollows the central Libyan stress domain witha NE-SW-directed horizontal maximumcompressive stress component thatincorporates the entire Sirte basin and majorparts of the Cyrenaica. A third in situ stressdomain occurs along the Cyrenaican coastalarea from Al Beda to the east. There, thestress field has a maximum compressivecomponent of NW-SE-direction. It issuggested that Tripolitania and the easternCyrenaica and their lithosphcric northernextensions are indenting the European platein a northwestern direction corresponding tothe drift direction of the African plate sinceabout 9 m.y. The Sirte basin is locatedbetween those framing indenters and wassubjected to extensional tectonics during thelate Mesozoic and most of the Tertiary, butmay have been under NE-SW-directedhorizontal compression since the lateNeogene.

Paleo- and Recent Stress Fields inNorthern and Central Libya from theCenozoic Structural Bearing

Karlheinz Schdfer

A selection of small-scale structuralfeatures have been applied as evidence forthe existence of horizontal paleo-stresseswithin Mesozoic and Cenozoic platformcarbonates of northern and central Libya.Major tectonic elements such as the lateMesozoic evolution of the Sirte graben andhorst structures and the CenozoicTibesti-Garian volcanic chain have beenconsidered additionally. It is shown thatnorthwestern Libya was subjected to

horizontal crustal shortening in theNE-SW-direction from end-Cretaceous toUpper Oligocene with a climax duringMiddle to Upper Eocene. A differenttectonic regime with mainly extensionalmovements to the NE and volcanic activiywas contemporaneously effective from thevolcanic chain to the east. NorthwesternLibya is presently influenced by aNW-SE-directcd horizontal principal stressof a stress field that was created alreadyduring the Middle Miocene. This stress fieldhad a climax during the Upper Plioceneinducing a new volcanic episode but nomajor rifting in the Sirte basin.

It is concluded that the African plate whiledrifting NE-ward from Upper Cretaceousthrough end- Paleogene and movingNW-ward relative to stable Europpe since 10m.y. ago has induced the two tectonicregimes in northern Libya. The differentcrustal stress history in the Sirte basin maybe due to a continuous NE-ward motion tothe African plate after the indentation ofEurope during the Upper Cretaceous by theAdriatic promontory as the continuation ofAfrica from NW-Libya and Tunisia to thenorth.

Actuogeological investigations and theinterpretation of palaeo-environments inthe Sahara

Erhard Schulz

In recent years there was quite someagreement among palaeoecologists that theSahara of Pleistocene and Holocene timeshad a vegetation cover of forest in themountain areas and lush steppe vegetation inthe surrounding lowlands. Based on thisconcept optimistic speculations on theamount of groundwater stored in Pleistoceneand Holocene sediments were made. Theconcept was based on the interpretation offossil pollen spectra, but on very fewbotanical macro-remains. Further evidencewas taken from pre- and protohistoricalremains as well as from the type anddistribution of fossil lacustrine and fluvialsediments.

Detailed studies on the problem ofpresent-day pollen sedimentation conductedin 1969 in the Western Sahara and in 1977in Central and Southern Libya and NorthernNiger show that the concept has to berevised. A large number of those botanical

•S3

elements that were found in sediments in theSahara, are nowadays transported into thedesert from outside regions. Among thetemperate elements Pinus, Alnus, Quercusand others are deposited as far south asnorthern Tibesti or the Plateau du Mangueni.Pollen of mediterranean flora are equallywide-spreand and also indicate long-distancepollen transport over several thousandkilometers.

Based on these observations it can nolonger be deducted from the fossil pollenspectra that the Pleistocene and Holocenevegetation cover was completely differentboth qualitatively and quantitatively.

Taking the few macro-remains andcarefully interpreting the pollen records, onecan only assume that the vegetation coverwas somewhat more dense than today, butthat the vegetation was of a similar type astoday. For the mountain areas we have toexpect a dry mediterranean shrub vegetation,but no forests.

In regard to groundwater resources oneshould therefore not overestimate theamount of recharge that may have takenplace during Pleistocene and Holocenepluvials.

A contribution to the Hydrogeology ofSiwa-Giarabub area (Egypto - LibyanBorder)

Abdu A. Shata & Mohammad A. Tamer

In this area, the strate of hydrogeologicalinterest are composed of a fissured limestonecomplex at top and a clastic complex at base.The upper complex, having a thickness ofabout 700 m, belongs to the Tertiary(Miocene and Eocene) and to the UpperSecondary (Upper Cretaceous Turonian).The lower complex, has a thickness of about2600 m and its ages ranges from the MiddleSecondary (Lower Cretaceous) to the LowerPrimary (Cambrian). Facts from the widerregion indicate that the two complexes arehydraulically connected, at least in part. Theground water of the upper complex is tappedfrom natural springs as well as from drilledboreholes and the piezometric level dropsfrom about 24 m above sea, level in then o r t h w e s t e r n p o r t i o n of t hemorphotectonical depression, to about l i rnbelow sea level in the opposite direction,(souheast). The salinity increases in thatdirection i.e. from northwest to southeast.

and the range is rather wide, i.e. from about1 500 ppm to about 8000 ppm.

With regard to the lower clastic complex, ithas a wide geographical distribution in thesubsurface and outcrops in a narrow localityin the northwest direction (Gabal ElAkhdar) and also in several places in therainy areas to the south (Chad, Sudan,Nigeria... etc).

In some wells drilled in Siwa Oasis, thepiezometric level of the ground water of thiscomplex is about 100 m above sea level andthe salinity is subject to wide variation (thelower horizons contain highly saline water ofthe order of 25,000 ppm, whereas in theupper horizons the salinity is less than 1000ppm; occasionally, however, a fresh waterhorizon is wedged in bracksh waterhorizons). The hydrology of the clasticcomplex in Siwa-Giarabub area is essentiallyinfluenced by the regional situation of thegreat arteries basin in NE Africa and islocally modified by the relatively high rainfall on Gabal El Akhdar. Dating of the waterfrom the carbonate complex has beenattempted, using the C 14 — method, andthe results point to the fact that the groundwater is, in part, Fossil water (25,000 to40,000 years). This leaves the door open fordiscussion that the ground water in Giarabub— Siwa area has been accummulated duringone or more period of the pluvial interval(Pleistocene).

Quaternary sedimentation of thewestern coastal plain of the Gulf of Sirte

N. S. Sherif

The Western coastal plain of the Gulf ofSirte covers an area of about 1,000 sq. km.and consists of several well definedphysiographic features: an inner barrier witha sabkha depression to landward succededseawards by an outer barrier enclosinganother sabkha depression.

The barriers consist of beach-dune ridgecomplexes, which reach heights of up to15m. above sea level. They are composed ofquartzose-carbonate sand and show differentdegrees of lithification. The sabkhadepressions are enclosed basins, remains ofinfilled lagoons, with surface levels belowthat of the present sea level, and are sites ofdeposition of modern evaporites.

Two major transgressive events formed thephysiography and the sedimentary pattern of

this coastal plain. The earlier transgression oflate Pleistocene age reached a level close tothat of the present sea and formed a barriedisland and lagoon, today preserved as theinner barrier and sabkha. The Flandriantransgression led to the sea reaching itspresent level just prior to 3.650 years B.P.,and it appears to have spilled into the olderlagoon behind the inner barrier.Subsequently, the outer barrier developed toenclose a lagoon to landward. The inletswhich allowed this penetration of marinewater into the inner and outer lagoonsultimately became closed and consequentlythe lagoons developed into the present dayinner and outer sabkha depressions.

Clays and claystones in Libya

Jifi Sindeldr and Pavel Jadrnicek

Regional geological mapping at a scale of1:250,000 in northern and central Libya,surveyed on behalf of the IndustrialResearch Centre, Tripoli, as well asexploration for iron ores, clays andclaystones in central Libya yielded severalnew occurrences of clayey sediments and alsocheccked some of those that had been knownbefore. Qualities of some of theseoccurrences correspond to the first-classceramic raw materials while others appear aspromising for possible industrial exploitationin the future.

Probably the best ceramic raw materials inLibya occur in the Upper Devonian strata inthe Wadf Shatti, accompanying the iron-oredeposits. The lower deposit (in the BasalSandstone Formation) is represented bywhite, thin-bedded, exceptionally compact,illite-kaolinite claystone with varyingadmixture of silty-sized quartz. In the upperdeposit (The Roof Beds Formation), theprevailing types are either black or grey clayshales or their altered equivalents. Apartfrom T-kaolinite, the most significantmineral present is mica, 14 A-mineral whileiron oxides, carbonates and sometimessulphates are subordinate. Petrologicallyeven technologically, the raw materialresembles the English "ball clays". In thenortheastern vicinity of Sebha exposedkaoolinite claystones are younger ingeological position (they probably belong toMesozoic Era). They are almost grey-whiteto white, their conchoidal varieties areflint-looking. These claystones will be used

ground as a binding agent in the productionof fireclay bricks.

Corresponding kaolinite claystones cropout also in basal horizons along the wholelength of the Jabal Nefusa escarpments(northern Libya). The most promising arethe Triassic to Cretaceous kaoliniteclaystones belonging to the Abu Shayba andKiklah Formation. Light grey claystonesoccurging on the western margin of the AlKhums map sheet contain, besidesT-kaolinite, also quartz and small amount ofmica and calcite. Mineral compositionsuggest the possibility of production ofrefractory ware whereas the coloured types(red and occasionally greenish) are suited forcommon types of stoneware. Nowadaysknown clayey sediments on the map sheetTarabulus are of somewhat lower qualities.The Abu Ghaylan deposit and clays. andclaystones in the Kiklah and Sidi as SidFormations contain, apart from kaolinite.mica and quartz, even 14 minerals, I-Mstructures and Fe and Ti components whichgive the rock its yellowish, grey or greenishgrey colouring. Frequent are also thehematite types of claystones. Handspecimens studied from the Yafrin andGuasscm deposit suggest that a production ofstoneware and bricks is possible.

In Turonian and younger sediments greenclays and claystones have been frequentlyfound. The rocks for detail examination werecollected near Mizdah (the Oasr TigrinnahFormation), along the main road on thenorthern part of the map sheet Al Washkah(Maastrichtian ZimSm Formation) and onthe north of the map sheet Darnah nearUmm or Razam (Miocene Al FaidfyahFormation). Besides illitc and pM-kaolinite,the essential mineral present in green clays ismontmorillonite. Alkaline chloridessulphates and nitrates are significantaccessories. The clays were tested andproved as satisfactory expanding material.After beneficiation the clays could be usedeven for other industrial purpose.

Attention was also paid to varicoloured(usually red-brown) calcareous clays ofQuaternary in age that occur on the Darnahmap sheet. These clays are mostly composedof kaolinite, calcite, Fe- and Al- oxides andhydroxides.

Structural control of Ground-water flowin the Mesozoic sandstone aquifers of

the Eastern part of Jebel, Nefusa, Libya

G. D. S. Singh

Sub-surface occurrence of the Mesozoicsandstone aquifers in the eastern part ofJebel Nefusa has more or less beenestablished. The reservoir so developedconstitutes perhaps one of the most powerfulground-water bodies in the whole of theJamahiriya. The reservoir thickness,constituted of undifferentiated Kiklah,Kabao and Abu Shaybah formations hasbeen estimated around 100 metres.

Ground-water flow is governed more bystructural elements of subterranean andregional origin, than any thing elesc. Thisphenomenon is clearly reflected on thepiezomctric head differential analysis withrespect to Beni Walid and Tarhuna. Thedifferential works out to be 120 metres.Piezometric elevations at Beni Walid andTarhuna are 200 and 80 metres above themean sea level respectively. This obviouslyindicates that the ground-water flow occursfrom south to north and north-east with anaverage gradient of 1 in 7*50 approximately.

The postulate that the reservoir slopesgenerally in a southern direction as againstthe northern slope of ground water surface isdifficult to reconcile, but this is what fieldanalysis proves to be. Elevations of the uppersurface of the reservoir calculated again interms of these two focii, reveal that they are500 metres below the mean sea level at BeniWalid, and about 50 metres above the samedatum at Tarhuna. Thus, an approximategradient of the reservoir works out at 1 in163. These findamental hydrogeologicalparameters, in addition to several others, arestrong evidence in support of the hypothesisthat the ground-water flow is structurallycontrolled. The resultant effect of all thesecontrols motivates sub-surface delivery ofwater into the Gefara Plain between themeridians 13°10' and 14°15' at anapproximate rate of 1170 litres per second.

Total intensity aeromagnetic map of theJabal al Awaunat area, southeasternLibya

Deb Shankar Sinha

Airborne geophysical survey employingmagnetic and gamma-ray spectrometricmethods was carried out in an area of about29.300 square kilometres during 1973 in the

Jabal al Awaynat region of southeasternLibya. The survey was restricted to thePrecambrian and the surrouding formations.In general, the Precambrian basement ismagnetic compared to the surroundingformations. The northeast-southwesttrending linear alignment of magneticgradients at the central part of thePrecambrian area separates it in two blocksand could indicate a deep fault characterisinga sort of graben or a petrographic change inthe Precambrian rocks. The presence ofwidespread magnetic materials ironstones,dolerites and basic granulites rawher than thegneisses themselves may contribute to thehigh magnetic level in the basement. There isgood correlation between the majornorht-south, northeast, east-northeast andeast-west trends of linear magnetic featuresand observed tectonic trends in basement.The syenites and granites of Jabal Ark'n'u andJabal al Awaynat are magnetically similar tothe basement rocks which they intrude butthe granites of Jabal Babuar and to lesserextent, Jabal al Bahri appears as magneticlows in relation to basement. The widespreadTertiary trachytic plugs and ring structure inthe west of the area are clearly depicted onthe magnetic map. A number of small butstrong magnetic anomalies located in anortheast trending zone between JabalArknu and Jabal al Awaynat is associatedwith lenses of quartz-magnetite-hematiterock in the basement.

On the application of Geophysicallogging in the Assessment ofGroundwater Potentialities ofGaddames - Hamada Basins

5. C. Sinha

This paper serves to illustrate the uses ofgeophysical logs in the assessment ofgroundwater potentialities in the Goddames- Hamada basins. An area of about 170.000Sq. Kms, bounded by Jebel Nefusa to thenorth, Gargaf Arch to the south, Tunisia -Algeria border to the west and the adjoiningSirte basin to the east, has been investigatedby interpreting borehole geophysical andgeological data from 105 Oil wells and 40Water wells.

The oil well data consisted of lithology,stratigraphy and geophysical logs recordedusing conventional resistivities, radiometric,

56

micro-devices, porosity logging, thermal andmechanical logging techniques. All these logshave been interpreted in the Office of theSecretariat of Dams and Water Resources inlocating aquifers and computing their salinityand porosity. The interpreted data has beenplotted as 14 no, geological cumhydrogeological cross-sections. The paper isillustrated with "5 such cross-sections and 2regional maps showing details on two of themost promising and extensive aquifers in thearea - Chicla (Lower Creataceous) and RasHamia (Teiassic).

Hydrogeological studies usingGeophysical logs in Murzuk basin

S. C. Sinlia and S. M. Pamky

This paper dels with a preliminary study ofthe groundwater possibilities in a 30,000 Sq.Kms area of Murzuk Basin bounded byLatitudes 25° - 27° N and Longitudes 13° 30'- l."5c O' E. The paper is illustrated with onehydrogeological section.

Geophysical data from 3 oil wells and 2deep water wells have been analysed for thisstudy. Geology of the area could beunderstood mainly from the Oil well andwater well files and party from the mapspublished by Conant & Goudrazi andAmerican Overseas Petroleum Limited.

The area under investigation is a part of asynclinal basin where the rock formations aresloping gently from north to south. Rockoutcrops show older formations (Devonian)to the north and the younger (Tertiary) tothe south. The present investigation revealsan increase in thickness of sediments fromnorth to south. These rocks range in agef r o m w i n d b l o w n s a n d s t oCambro-Ordovician. Some of theintermediate members in these sediments,Jurassics to Permian, either tend to pinch outin their northern extension or progressivelythin down.

Aquifer features have been indicated inthe granuler sediments of Lower Cretaceous(Nubian), Jurrassics, Carboniferous andCambro-Ordovician rocks. Most extensiveand good quality aquifers exist in Nubiansandstones in almost the whole area exceptto the north where older rocks are exposed.Next best are the Jurrassics in the south and

Cambro-Ordovician to the north. Thetopographical and structural features suggestartesian to sub-artesian conditions in theseaquifers. As Nubian aquifers are exploitedappreciably through shallow tubewells in thepopulated parts of the investigated area, theCambro-Ordovician and Jurrassic aquifersmay act as stand by sources of potablesubsurface water and also to minimiseover-explitation of the Nubians. Aquifers inCarbonifeous rocks are saline and have littlepractical use.

The investigation has revealed that majorpar of the Gaddames - Hamada basin is apotential source of potable subsurface water.The main aquifers are, — Garian, Chicla andRas Hamia.

Irregular lateral extension and erraticquality distribution (both vertically andlaterally) in the Garian aquifer suggest thatthis aquifer may not follow a well definedpattern. Chicla is by far the best aquifer inthe region, — extensive, permeable, potable,and has considerable effective thickness. Thisaquifer is often under artesian tosub—artesian conditions due to favourbalesubsurface structure and topography. RasHamia, though deep seated, is the secondbest aquifer in the area. This aquifer is alsofresh-water bearing in major part og the areaand is also under pressure. In some partswhere Garian and Chicla are absent or pooror uneconomic, Ras Hamia is there tocompensate and meet the waterrequirements. Toward the southern limit ofthe investigated area, the Chicla and RasHamia aquifers tend to combine into a singleaquifer unit.

The results of the present investigationmay be used in formulating detailedhydrogeological programmes in some partsof the Gaddames - Hamada basins, with theultimate objective of developments in a fewfavourable areas of these basins.

Meta - Halloysite from the Wadi Rumlya,Djebel Nefusa, - Its Occurrence andorigin

Werner Smykatz-Kloss

Abstract. The walls of the Wadi Rumiyanear Yefren, part of the Djebel Nefusaescarpment, show the rocks of the wholeKikla and Sidi Said formations. Thecrossbedded, yellowish-brown Kiklasandstone includes lenses and layers of

57

greenish-grey and reddish calystones whichwere studied by X-ray diffraction anddifferential thermal analysis. These clays,varying in thickness from few cm to 2-3 m,are synsedimentary in origin. They consistmainly of the kaolin group mineralweta-halloysite, Al2[(OH)4Si2Os]. x H2O; xbeing between O.I and Q.~i. Themeta-halloysite shows all states of structuralorder, from strongly disordered towellordered, but most samples exhibitstructures being clearly disordered after thecrystallographic b-axis. Discussion of thegenesis and diagenesis of the clay:synsedimentary formation of halloysite,Al2[(OH4Si2O.v2H2O, during the cretaceousKikla period and in a near-shore (probablulagoonal) marine environment, andalteration of this halloysite to meta-halloysiteby diagenetic processes. The possibletechnical application of the clay is discussed,too.

Mg- deficient dolomitefrom the Ain TobiMember of the Jabal Nefusa,Tripolitania

Werner Smykatz-Kloss

The chief mineral of the Ain Tobi Member(lower part of the Sidi As Sid Formation) ofthe Jabal Nefusa, Tripolitania, is aMg-deficieni dolomite, whoch is associated byquartz and small amounts of calcite, haliteand Mg-sulphates. This dolomite, showing a••normal" X-ray pattern, exhibits a strangedecomposition behavior: in DTA curves thefirst endothermic deflection (which is due tothe decomposition of the MgCCh componentof the dolomite structure) is lowered morethan 150° C compared with '"normal"dolomite. The reason for this decreasedstructural stability is the lack of 5-10% of theMg of the structure. This deficiency of Mg ismost probably reasoned by slightly acidicweathering solutions which leached the Mgfrom the structure. In the lower part of theAin Tobi lavers the dissolved Mg isprecipitated as epsomite, MgSO.i- 7 H:O,which quickly alters to hexahydrite,MgSOi- 6 ihO- Both Mg-sulphatesoccur as secondary fillings of cleftsand cavities, together with small amountsof halite.

Oolitic Magnetite from Wadi Al-Shati,Fezzan, Sedimentary or Metamorphic inOrigin

Nakhla, F. M. and W. Swykatz-Kloss

The Libyan iron ore deposit occurring inWadi Al-Shati area, Fezzan, is dominantlycomposed of magnetite Fe + 2Fe2 + 3O4 whichreveals well developed oolitic texture,indicating that is was most probably formedunder shallow marine environment ofdeposition. According to Goudarzi and otherworkers, Wadi Al-Shati iron mineralizationis believed to be of syngenetic sedimentaryorigin. However, the genesis of magnetiteremains a questionable problem since it canhard ly be exp l a ined from thesedimentological point of view. It is wellknown that magnetite could be formed inappreciable amounts under a relatively hightemperature and low negative Eh values.Such favourable physico-chemicalenvironment might be fulfilled by contact orregional metamorphism.

Mineralogical and geochemicalinvestigations, by microscopic, DTA andX-ray methods, of more than 60magnetite-rich ore samples from South Tarutin Wadi Al-Shati has shedded some light onthe genesis of magnetite revealing whether ithas been formed by sedimentary ormetamorphic process or it is of polygenicorigin. The present study has discerned thatWadi Al-Shati iron ore deposit was initiallydeposited, under marine conditions, assynsedimentary goethite and berthierinc(chamosite) during Upper Devonian time.The post mineralization processes, includingdiagenesis and low-grade metamorphism,resulted in the partial transformation ofgoethite and berthierine to magnetite whileretaining the original oolitic texture of theore. Heat was the main agent ofmetamorphism and was most probablyrelated to Tertiary volcanic activity which ismanifested by the extensive basaltic flowsoutcropping in the northern and easternparts of Wadi Al-Shati area.

Mineralogy and Geochemistry ofSynsedimentary iron Hydroxides and ofConcretionary Goethite from the WadiRumiya, Djebel Nefusa

Smykatz-Kloss, W and S. H. A. Shah

In the Wadi Rumiya near Yefren, the

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sandstone of the Kikla formation containsseveral lenses and layers of claystones whichare commonly bordered by small bands offine-grained iron hydoxides. Besides thistype of synsedimentary goethite a secondtype of iron hydroxides occurs, formingbrown concretions of goethite mainly in thelower par of the Kikla formation. Theseconcretions vary in size between 2 and 80 cmin diameter and include a greenish claystoneconsisting of a true, well-ordered kaolinite.Both iron hydroxides, the synsedimentarylayer- type I and the diageneticconcretion-type II contain the same ironmineral (goethite) but differ in the structuralstate (in the degree of structural disorder).ofthis goethite, in their accessories and in theirtrace element patterns.

New Findings of Tertiary fauna in JabalHasawnah /Central Libya/

Zdcnek V. Spinar, Zbynek Roiek

In the course of geological survey ofcentral Libya, organised and supported byIndustrial Research Centre, Tripoli, a newfreschwater series of Tertiray age wasdiscovered and named Tar&b Formation. Theprofile of the type locality of this scries/western foot of Jabal Hasawnah; on thegeological map of Libya 1: SO,000 sheet2081-11, point No 20) demonstrated that theseries is formed by clay sediments withseveral thin carbonatic beds. Thesesediments, arisen by filling the small basin,are of the oligocene age, according to recentstudy. In open parts of the profile Scarbonatic beds were found. The uppermostone is sterile, the remaining 4 arcfossiliferous, containing gastropod shells,numerous skeletons and imprints of fishes(Pisces), frogs (Anura) and scarce remains ofmammals (Mammalia: Hyracoidea).

Gastropod shells were found both incarbonatic beds (layer II-V) and in silicifiedfragments of rock found on the surface in thesurroundings of the profile. In carbonaticbeds, 2 specimens belonging probably to thefamily Cochlicopidae or to the familyVertinidac were found. Owing to the factthat shell apertures with decisive diagnosticcharac te r s are des t royed , exactdetermination will not be possible. Insilicified fragments found outside the profile2 species of gastropods were ascertained.The majority of relatively well preserved

shells probably belongs to the familyMelanidae. Another specimen which isstrongly demaged probably belongs to thefamily Succineidae.

In the locality under study, the fossilremains and imprints of fishes arepredominant among other vertebrates. Theyare relatively well preserved and abundant.The material for study consists of more then100 specimens, which are almost completeand many fragments. According to our studythey belong to the species Palacochromisrousseleti Sauvage, 1907 (family CichlidaeBlecker, 18S9). In the material we had atour disposal there were fishes of medium sizeattaining the body length S3-120 mm(without tail fin). They possessed aconspicuously large head (about one third ofthe body length). The dorsal fin was long andcontinuous, with 12-13 firm spines and about12 soft rays. The anal fin consisted of 3 hardspines and 8-9 soft rays, the abdominal fin of3 hard and S soft rays. The pectoral fin wasnot supported by any hard spines andconsisted only of 12 soft rays. The distalmargin of the caudal fin was almost straightand the fin was supported by 22 rays. Thescales were of the ktenoid type, usually with7-12 radial lines. Intermaxillarc and dentalebore several rows of long and conical teeth.

In laminated limestone the remains offrogs were also found: IS incompleteskeletons and 7 imprints without preservedbones. They are small pipid frogs attainingbody length of 42 mm. The frontoparietals ofadult specimens are fused. These bones arenarrow on the rostral end, while on thecaudal end they arc robust and vaulted. Theyfuse with occipitalia latcralia, and in somespecimens also with ossa prootica. Oticcapsules are conspicuously large, and in somespecimens separated by the groove fromfrontoparientals. The vertebral column andpelvis are similar to those of Xenopus lcavisand consists of 9 opisthococlous vertrebrae.Sacral wings arc slightly narrower than inabove mentioned recent species. Femur ishorter then cms. Astragalus and calcaneusare separated. Metacarpals and metatarsalsare long which demenstrates the permaneltywater-dwelling habitat of the frogs.Preliminarily we can state that these frogsbelong to a new genus, considerably differentfrom the genus Xenopus.

Among other findings there are also 2incompletely preserved skulls, 1 almost

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complete postcranial skeleton and 3fragments of various body parts of a mammalTitanohyrax palaeotherioides (Schlosser,1910) (Hyracoidea: Geniohydae). Dorsalside of the skull No L-RS-77 is quite smooth.Teeth can be studied only in lateral view;only PM2-4' Mi-: PM'-4 and M 1-2 aredistinct. M: dex. is solenodont The otherpreserved teeth are brachiodont, withconspicuous cingulum. As the specimens areyoung and immature, the teeth are rathersmall and the hindmost molars are stillhidden inside the jaw. Howver, thedescription of teeth form agrees with datafrom the literature. The best preservedpostcranial skeleton No 4-L-R§-77demonstrates that the specimen is as large asa big rabbit or a cat. The adult animalcertainly was much larger. The outline of thefrontal part of the skull No 1 vL-RS-77,together with the nasal bone and small lowerincisor, are evidence of a form with a longrostrum.

Groundwater studies in the Triangle benGhashir-Tajoura-el Zawia (Tripoli,Libya), using radioisotope TechniquesF. M. Swailem, A. M. Eskangi, R. E.Shoheib and R. M. Mabrook

The problem of continuous lowering ofunderground water level due to exhaustivep u m p i n g , in the t r i a n g l e BenGhashir-Tajoura-El Zawia makes it essentialto study recharge processes in this areaPeriodical field and laboratory works havebeen executed twice per year for a period ofabout five years. The work were undertakenin six representing localities in the areaduring the recharge time (winter time) andthe discarge time (summer time).

The work includes complete chemicalanalyses of water, tritium measurement,determination of aquifer parameters asproductivity, transmissibility and storagecoefficient; and identification of directionand velocity of groundwater flow usingradioisotope tracer techniques. The resultsare interpreted considering the geologicaland hydrogeological conditions of the region.

Geochemical and MineralogicalInvestigations on evaporites of theZouila Sabka FezzanHeinz J- Tobschall and WernerSmykatz-Kloss

The sabkha of Zouila is located about 120km S of Sebha in central Fezzan. It is nearly12 km long (E-W) and 2 km broad in S-Ndirection. Because of being dry during 11months of the year, there are only few spotsat the deepest depression of the salt lakewhich are filled with water. For the presentstudy 20 samples have been collected fromthe rim of these "water holes", from twocross sections and from the hills of thenorthern surrounding area. Geochemicalanalyses for alkali and earth alkaline metals,for Fe, Si, Al and Mn, and mineralogicalanalyses by means of X-ray diffraction havebeen carried out. The variation intheamounts of occurring minerals halite,sylvite, carnallite, glauberite, gypsum,anhydrite, mirabilite, thenardite, quartz,goethite, kaolinite, calcite, and dolomite andthe genesis of these minerals have beendiscussed.

A Review of the Investigations on theWadi al Shatti Iron Ore Deposits,Northern Fezzan, Libya

T. M. Turk - A. K. Doughri andSyumadus Banerjee

This paper reviews the results ofinvestigations carried out by the FrenchGroup between 1971 and 1976 in two stages,on the iron ore deposits of the Wadi al Shattiin northern Fezzan.

An area of about 3,000 sq.km. wasgeologically mapped on 1:40,000 scale, fromeast of Ash Sheb to west of Gottah, adistance of about 160 km. Further detailedmapping of about 255 sq.km. was done on1:10,000 scale in the Ashkeda and SouthTaroot areas.

The iron ores occur in the DevonianAouinet Ouenine Formation of Jabal Fezzan,in a 140 m thick sedimentary sequenceranging in age from Upper Frasnian toStrunian (Upper Devonian). There arethrece important iron ore horizons.

The best type of the ore is the magneticreduced ore having a proved reserve of 420m. tons with about 55% Fe content, alongwith a proved reserve of 375 m. tons pfnon-magnetic reduced ore and 100 m. tonsof oxidised outcropping ore in the SouthTaroot area, about 40 km west of Brak. Thetotal inferred reserve of all types of ores isabout 3.5 billion tons, Fe content varyingbetween 35% and 55%.

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The studies also covered the mining,beneficiation, agglomeration, reduction,marketing, transport etc. for the possibleexploitation of these ores for an Iron andSteel Industry. The limestone and dolomiteresources of the area were also investigatedfor the purpose.

Palaeozoic Sedimentology of theSoutheastern part of the Kufra Basin,Libya: a model for oil Exploration

Brian R. Turner

The Palaeozoic succession in thesoutheastern part of the Kufra Basin, Libya,has been divided into 10 sedimentary faciesrepresenting fluvial, tidal, subtidal, shorefaceand marine shelf depositional environments.Repetition of facies is attributed to coastlineinteraction with a braided alluvial plain.During active fluvial input the depositionalsystem prograded seaward due to a switch inthe depositional loci or increase in regionaltectonism. The abundance of deformedcross-beds in the fluvial deposits, inferred tohave resulted from the action of current dragon a sand bed liquefied by earthquake shocksfavours the latter interpretation. Inactivity ofthe fluvial system due to decrease in regionaltectonism resulted in marine transgressionand drowing of the coastline. The lack ofpreserved barrier complexes and presence ofsubtidal sand shoals and tidal flat sequencesindicates a high tidal range (macrotidal >4m), possibly analogous to contemporarymacrotidal coastlines such as the North Seacoast of Germany.

Continental reconstructions indicate thatthroughout most of Palaeozoic time theKufra Basin lay in the belt of prevailingwesterly winds (between latitudes 3."5° and60°S). However, since protection from thesewinds was afforded by two areas of positiverelief centred on Tibesti and Jebel Uwaynat,and since wave power depends on windfetch, it is unlikely thatn the Kufra coastlinewas buffetted by high winds and waves undernormal conditions.

The presence of strong tidal currentsimplies that the Kufra Basin was connectedwith an open (Tethys), probably through theQattara embayment in the northeast. Thegeneral lack of silts and muds in attributed tothe nature of the fluvial input, wave and tidalprocesses in nearshore areas and thehydrographic setting of the basin.

The only suitable hydrocarbon sourcerocks in the basin are the offshore shelffacies of the Silurian Tannezouft Formation;although this is thin, has an immature carboncontent, and coincides with few suitablestructures.

One exception occurs in the northwestwhere structure, local increase in thickness atdepth (2000 m±) and presence of reservoirrocks provid one of the few petroleumprospects in the basin; elsewhere conditionsare generally unsuitable. Stratigraphicrelations indicate that the Palaeozoicsuccession in the southeast part of the basinforms the exposed limb of a broad synclinalstructure trending northeast-southwest.Faulting along this limb has exposed hithertounrecognised •Cambro-Ordovician sedimentsbut hydrocarbon entrapment along thefaulted limb of the fold is unlikely due toinadequate impermeable seal rocks and thegenerally small amount of displacementalong faults compared to thickness ofreservoir sands.

Because few structures coincide withdepositional facies containing optimumreservoirs, stratigraphic traps becomeimportant as sites of oil and gasaccumulation. However, the facies sequencelacks any major progradational deltaicsuccession or significant transgressivcwedges, and since little mud was deposited inthe basin there are few effective seals forsand reservoirs and no interfingering of sandsmuds typical of multipay reservoirs.

Facies changes and depositional pinch-outof sands amenable to stratigraphicentrapment are infrequent and generallysmall and localised with little potentialproduction for exploration incentive,especially in view of the distance from Kufrato the nearest sea terminal, some 1000 km tothe northwest. Depositional pinch-outs mayexist in the Cambro-Ordovician succession ofJebel Archenu when traced northwards intothe subsurface, although they would requireextensive drilling to prove.

Meteorite Impact Structures, SoutheastLibya

James R. Underwood & Edward P. Fi.ik

In southeast Libya two circular structures80 km apart have been identified asmeteorite impact structures because of: (1)structural geometry, (2) style of deformation,

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and (3) microscopic evidence ofhigh-pressure shock metamorphism of quartzgrains. The structures are designated,informally, the BP structure (2.8 kmdiameter; lat 2."5°19'N and long 24°20'E) andthe Oasis structure (11.5 km diamtcr; lat24°35'N and long 24°24'E).

Although no meteorite fragments, shattercones, impact glass, Ni-Fe spherules, ormegascopic breccias were found at eithersite, samples of sandstone from bothstructures show widespread shockmctamorphic effects in quartz, e.g. cleavageand planar features (shock lamellae) withprominent orientations in the (0001),(1122), and (1011) planes and lessprominent orientations in the (1013) and(1012) planes. The Libyan samples showorientations of shock lamellae that aresimilare to those in quartz from shockedCoconino Sandstone from Meteor Crater,Arizona. Dislocated quartz grains arecommon, and interstitial brow glass, similarto Fladen from other impact structures,occurs in some samples (French and others,1972, 1974).

These structures were detected originallyon orbital images (Kohman and others,1976), and the smaller one was described byMartin (1969) who suggested it might be ofmeteoritic origin. The structures lie 125-165km northeast of Kufra oasis where surfacerock is quartz conglomerate, sandstone, andsiltstone of the continental Nubian Sandstone(Lower Cretaceous). Subsurface geology ofthe Kufra basin is virtually unknown, butlithology of outcrops at the margins do notsuggest the presence in the basin of rock thatcould produce the structures by diapiricdeformation. The nearest surface occurrenceof igneous rocks is 200 km to the south inthe area of Jebel Arkenu and Jebel Awenat(Goudarzi, 1970).

Concentric circular ridges of deformedrock that compose the structures rise asmuch as 100 m above the surrounding desertplain and constrast in form with the buttes,mesas, and northwest trending ridges typicalof the region. Although in lithology andintensity of deformation the structures aresimilar, the smaller one has a rim synclineand a distinct central block or peak, whereasthe larger one does not. In both structures,dips range from zero to vertical; some bedsare overturned. Faults are not conspicuous;most have displacements less than 20 m and

are related to folds which characteristicallyhave gently plunging axes tangential to thestructures. Lack of marker beds andobliteration of texture and bedding byextensive iron-oxide impregnation limitstratigraphic correlation and structuralinterpretation. The structures are dated onlyas post-Nubian; their close spacing and theirsimilar weathering and erosional statesuggest that they were formedsimultaneously or nearly so, by doubleimpact.

The occurrence of the unique anddistinctive Libyan Desert glass, discovered in1932, lies only 150 km east of the Libyanstructures. The proximity of the structures tothe glass site and the lack of disturbed strataof Nubian Sandstone in the area of the glassoccurrence, suggest that the glass may havebeen produced by the impact events thatproduced the structures. The fission trackmethod has been used to date the LibyanDesert glass at 28 m.y. (Storzer and Wagner,1971).

Micropaleontologic record of theMessinian event at esso Libya inc. WellB1-NC35A on the Pelagian Platform

J. L. van Write, J. P. Colin and R. Lehmann

Esso Libya Inc. drilled well B1-NC35A in1977 about 140 km N.E. of Tripoli offshorein 460 meters watcrdepth. Sidewall coreswere shot from the upper 500 meters belowmudline because no cuttings had beenrecovered from that interval. The cores showthe presence of cvaporite between marls.

The marl above the evaporite is of EarlyPliocene age with Globorotalia margaritaeBolli & Bermudez and a middle to upperbathyal origin is suggested by a highplankton/henthos ratio and the presence ofsuch forms as Uvigerina spinicostataCushman & Jarvis Bulimina aculeatad'Orbigny. The marl below the cvaporite hasprimit ive Rectuvigerina creten.1 is(Meulenkamp) snd lcftcoiling Globorotaliaacostaensis Blow which suggest a middleTortion age, it probably originated issomewhat shallower depths (upper bathyal toouter peritic) as plankton is less dominantthan above and U. peregrina Cushman andB. striata d'Orbigny represent the generaUvigerina and Bulimina.

A similary situation was found in cuttingsof a nearby well where the interval with

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cvaporites yielded the characteristic "LagoMare" fauna of the mediterraneanMessinian. The reasonable assumption thatthe evaporite at the Bl well also is ofMessinain age implies the presence of anunconformity at its base.

This paper describes some keyForaminifera and Ostracoda recovered fromthe sidewall cores, speculates on theimportance and the nature of theunconformity and concludes thatapproximately "500 meters of sediment wereeroded as a result of a significant drop insea-level.

Paleogene Vertebrate "Faunaand Regressive Sedimentsof Dor el Talha,Southern Sirte Basin, Libya

A. Wight

As the result of two expeditions led by Dr.R.J.G. Savage to Dor el Talha escarpment,in 1968 and 1969, a fauna comprisingtwenty-one different vertebrate genera hasbeen collected, representing mammals,reptiles and fish. The vertebrates were foundall along the ISO km length of theescarpment, and this paper describes fossilsfound at thirty four localities. Theescarpment extends in an east-west directionfrom the southeastern corner of the Haroudjbasalt massif, and forms the northern limit ofthe Serir Tibesti. The sedimentary sequenceexposed in the escarpment consists of a basalmarine unit with a coquina of oyster shells,followed, upwards by approximately 40metres of marine grey-green siltstones andcalcilutites of near-shore marine origin.These beds are overlain by 35 metres ofrhythmically-alternating white sandstones,green siltstones and claystoncs representingfluviatile channel, point bar and overbankdeposition. Capping this is up to 20 metres ofmature, yellow-brown sandstone, possibly offluvial or lacustrine origin.

The age of the 75-100 metre thickexposures is thought to range from UpperEocene at the base, to Lower Oligocene atthe top, by analogy with the Fayum depositsof Egypt and also by their stratigraphicalrelationship with the Paleocene toMiddle Eocene sections described by Furstfrom the other three margins of the SerirTibesti.

Stratigraphic and Micropaleontologicexpression of the mediterranean lateMiocene (Messinian) regression andearly Pliocene (Zanclean) trangressionin Northeastern Tunisia

Stephen K. Wiman

Evaporitic sediments deposited during theLate Miocene (Messinian) salinity crisis areexposed in northeastern Tunisia near thevillage of Raf-Raf and at Diebel Kechabta,south of Bizerte. The Upper Miocene Ouedbel Khedim Formation exposed thereconsists of bedded and nodular anhydrite,fresh-water limestone and diatomites, withintercalations of silty marls which haveyielded rare shallow-water benthicforaminifera, ostracodes and reworkedplanktic foraminifera. The Oued bel KhedimFormation is underlain by shallow-watermarls assigned to the Tortionian KechabtaFormation.

The Messinian sequence is unconformablyover la in at these loca l i t i e s bymicrofossiliferous marls of the LowerPliocene (Zanclean) Raf-Raf Formation.Benthic foraminiferal assemblages indicatethe Raf-Raf Formation marls exposed northof the Dorsale (Tunisian Atlas) weredeposited at inner to middle shelf depths.

South of the Tunisian Dorsale thestratigraphic expression of the Messinianregression is predictably dissimilar. Theyoungest Miocene sediments from south ofthe Dorsale are Saouaf Formation marls ofearly Tortonian age exposed at the extremityof the Cap Bon peninsula. The Messinian onCap Bon is represented by continentaldeposits of the Segui Formation. Highlymicrofossiliferous Raf-Raf Formation marlsare well exposed in quarries, streams androad-cuts in the Nabuel-Hammamet areaand provide information concerning thenature of the Early Pliocene transgression onCap Bon. The oldest Raf-Raf Formationdeposits on Cap Bon are assigned to theGloborotalia margaritae margaritaeinterval-zone (M PI 2 of Cita, 1975). Wellpreserved and diverse benthic foraminiferalassemblages have been used to estimate thatLower Pliocene Raf-Raf Formation marlsaccumulated at outer shelf to upper slopepaleodepths on Cap Bon, and plankticf o r a m i n i f e r a c o n f i r m t h a t t h eNabeul-Hammamet basin persisted throughat least early Piaccnzian time.

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Stratigraphic expression of evaporitic andcontinental sediments of Late Miocene age isfound on opposing flanks of the TunisianDorsale. The contrasts in the character of theMio-Pliocene boundary interval in these twopaleobasins (about 100 km apart) are due totheir disparate basin margin positions at thebeginning of the Messinian. Thepaleogeographic picture is furthercomplicated by tectonic activity which haspersisted from at least Middle Miocene toPleistocene time along the Dorsale. Creationof the relatively deep PlioceneNabeul-Hammamet basin is a tectonic eventwhich is probably Messinian in age, for nobasin of such depths is known to have existedthere earlier in the Miocene.

Zirconium contents in Jabal Nefusaphonolites and distribution of zirconiumin the rock forming silicate phases

L. Wirth

Zirconium contents were determined on17 phonolites of the northeast Jabal Nefusavolcano, with help of X-ray fluorescence.

The remarkable high values (600 to 2400ppm) correspond very well with the datagiven by Almond et al (1974), completingthem to the more eastern part of thephonolite occurrences.

Furthermore, the distribution of zirconiumwithin the different rock forming silicatephases was investigated by means of electronmicroprobe.

The contents and the location of zirconiumseem to have significance for discussions ofthe development of the Jabal Nefusamagmas.

Hydrogeology of Mesozoic Aquifers inWestern part of wadi al ajal

Marek Zaluski & Kamal I'.. Sadek

The G o v e r n m e n t A g r i c u l t u r a lDevelopment Project has been executed inWadi Al Ajal areas since 197*5.

Nearly two hundred water wells of thedepth ranged from 200 m to 500 m havebeen located in the narrow strip of 100 kmlong, in the western part of the valley anddrilled for that project.

The Libyan Office named ConsultingOffice for Drilling and Water Investigationswas requested to carry on the reporting jobfor that project, including subsequent

comprehensive hydrogeological elaboration.Basing on the data collected duringexecution of above mentioned project, thehydrogeological conditions of the area insubject have been described in that articleand presented on the background of generalknowledge of region. There is a great deal ofemphasis on the chemical composition ofwater. The rough model of ground watercirculation in that region is also presented inthe article.

The paper consists of 14 normal typedpages with two figures and two tables.

Hydrogeology and Hydrology of theJoufrah Area

Husni Zcino-Mahmalat

Hydrogeological studies, hydrologicalresearch based on flow and pump tests andobservations of the wells in theJoufrah-socna area show that adequatequantities of ground-water can be extractedfrom the upper Cretaceous artesian dolomiteaquifer for the Joufrah agricultural project.The long term drawdown in the projectwater wells is acceptable and the figurescalculated after completion of drilling andresearch at the Joufrah construction sitecorrespond approximately to the valuesreported earlier as well as to the figures usedfor the design of production wells, pumpsand power supply. An analysis of researchresults shows that the values used in thedesign have been derived from realisticcalculations.

The Joufrah project area is located in ahydrogeologically very complex area on theintersection of several structural andstratigraphic trends: the Sirte, Homra andMorzog Basins, the Hun Graben, and theDjebl Es Sawda volcanic massif. Thegeologic sections show wide distribution of abasin rim fades with predominant sandstonesand carbonates comprising importantaquifers. The widely distributed Paleozoicsandstone aquifers of the Morzog and Homrabasins extend to Joufrah and connect thisarea with these basins. The Joufrah area isprobably part of a very large, pressureconnected hydraulic system comprising mostof the Fezzan Region of Libya. Technicallycontrolled permeability channels as well asaquifer contacts are believed to connect theMorzog Basin east of the Gargaf High withthe Joufrah area along a pressure gradient.

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An inflow compensating ground-waterextraction in the Joufrah - Socna area istherefore expected. Hydrological evidencefor a hydraulic system extending beyond thedistribution of the Joufrah dolomite aquiferhas also been presented.

The section at Joufrah commences at thetop with Quaternary unconsolidated rockscomprising an unconfined, shallow aquifer oflimited capacity and poor water quality.

The upper Cretaceous dolomite andlimestone artesian aquifer, which is used forthe Joufrah and Socna projects, isencountered below a 100 to 150 m thickcover of partly calcareous shales with atransition zone of minor carbonate aquiferbeds at the base of shales.

The main aquifer interval of about 45 mthickness consists of fractured carbonateswith porosity and permeability stronglyenhanced by solution (Karst conditions)especially in the Socna area. The aquifershows good permeabilities throughout withlocal zones of extremely high permeability.The pressure level had been influencedalready at the beginning of the Joufrahproject by the Socna production and wasencountered at about 338 m above sea level.With ground elevations ground 300 to 330m, free artesian flow was obtained in theJoufrah and Socna wells. Flow rates varied,some flows exceeding 500 m3/h werereported.

To explore the section below the mainartesian aquifer the deep research well J -18(total depth 702 m) and a deep piezometer J- 18Z were drilled. Below the main artesianaquifer, a thin, undifferentiated Cretaceoussection was encountered. It representsprobably the onlap of the Cretaecous on theGargaf High. From 226 to 273 m anon-permeable shale-siltstone sectionyielded an upper Paleozoic, probablyDevonian, microfauna. This section isunderlain until the total depth of 702 m by asandstone aquifer correlating with theCambro-Ordovician and probably exceeding500 m in thickness. The basement was notreached in any well of the Joufrah-Socnaarea.

A vertical connection of the deep(Paleozoic sandstone) and the shallow (upperCretaceous dolomite) artesian aquifers isexpected along fracture zones, such as faultsconnected with the Hun Graben. Thesevertical fracture conduits are proved by

surface artesian springs, such as AinHammam north-west of Socna (see chapter10.5). Furthermore, hydrological evidencesupports the presence of a zone of lowpermeability underlying the dolomite aquiferand connecting it with the deep sandstoneaquifer.

A hydrological research program wasinitiated by the CAD on the Joufrahconstruction site, consisting of test welldrilling including the deep well J-18 longterm flow tests, pressure and well yieldmonitoring of all Joufrah and Socna wells,and installation of a meteorological station inthe Djebl Es Sawda.

The results of the observations and testswere used for calculations of the hydrologicalaquifer parameters especially the coefficientsof transmissibility T and of storage S. Thetests had shown a break in drawdowndevelopment after about 7 to 10 days of flowin J-10, indicating groundwater sources fromdifferent aquifers.

Values of T (in m3/ seem) and S havebeen calculated from numerous tests and alsoby various methods (Theis, Thiem, Jacob,Chow) from non-steady and steady stateflows and recovery during various timeintervals. Median values obtained for themain aquifer were T=2.7 x 102 and S= 1.1 x103 from long term tests, T= 1.4 x 10= andS= 2.3 x 104 from short tests. The Paleozoicartesian aquifer showed an average of T =1.1 x 101 m3/sec. m. reflecting the thicknessof the section, and S= 1.9 x 103.

For determination of the long termdrawdown in Joufrah an analog computermodel was calculated using the T and Scoefficients computed from long term tests.No rainfall recharge was used. The calculatedregional drawdowns ranged from 36.4 m and41.8 m below the present static water tableafter 50 years.

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BIOGRAPHIES

Second symposiumon the geologyof Libya5 5 y

University of Al-FatehFaculty of ScienceGeology Department

September 16-21, 1978TripoliSocialist People's Libyan Arab Jamahiriya

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YEHIA E. ABDELHADYLecturer, Exploration Geophysics, Cairo Univ. Egypt; Address: Geol. Dept. , Facultyof Sci., Cairo Univ. Giza, Egypt; Employement History: 1966-1967 Geologist, SafagaPhosphate Company, Red Sea County; 1967 Geophysicist, Gen. Petr. Co. Cairo; 1967to present, Geol. Demonstrator to 1970, Assistant Geol. Lecturer to 1974, Lecturer topresent, Geol. Dept. Faculty of Sci., Cairo Univ.; Lecturer Geophysics, Riyadh Univ.Saudi Arabia, 1974; Academic History: B. Sc. 1966, M.Sc. 1970, Ph.D. 1974.

GILAM ABDELGAWADChairman, Dept. Soil and Water, Univ. Al Fateh, Tripoli; Address: Faculty ofAgriculture, Univ. Al Fateh, Tripoli, SPLAJ; Employment History: 1969 teacherassistant and 1973 to present Chairman, Dept. Soil and Water, Univ. Al Fateh, Tripoli;Academic History: Univ. Al Fateh, B.Sc, 1968; Univ. California, Ph.D. (SoilChemistry) 1973; Society Affiliation: American Scientist (Sigma XI).

MOID U. AHMADConsultant in Hydrology, Geophysics and Geology, Ohio; Address: 125 Rolling HillsDrive, Athens, Ohio 45701, USA; Employment History: Water well design in Libyaand Kuwait (trough UNFAO); regional groundwater investigations and developmentof geophysical tecniques, Pakistan; geological and hydrologic research and consultancyin Ohio; Professor of hydrology and geophysics, Ohio Univ., USA; Academic History:New Mexico Inst. Mining and Technology, M.Sc. (Groundwater hydrology); Univ.London, Ph.D.; Society Affiliations: European Expl. Geophysicists, Expl.Geophysicists (USA), National Water Well Ass., Am. Geophys. Union, IWRA, Int.Ass. Hydrogeologists.

THAMER K. AL AMERResearch Student, King's College, Univ. London; Address: King's College, Strand,London WC2R 2LS, UK; Employment History: 1970-1975 Geologist, Iragi MineralsInst.; Academic History: Baghdad Univ., B.Sc. 1969; Suphur Exploitation course,Poland, 1970; presently engaged on research for a Ph.D. since 1975; SocietyAffiliations: Iraq Geol. Soc, British Micropal Soc, Palaeontological Ass., Am. Ass.Strat. Palynologists, Commission Internationale de Microflore de Palaeozoique.

MARIE-PIERRE AUBRYAssistant Scientist, Univ. Paris, France; Address: Univ. p. et Marie Curie, Laboratoirede Gcologie des Bassins Sedimantaires, Tour 15, 4 stage, 4 Place Jusicu, 75005, Pariscedex 05, France; and temporarily, Woods Hole Oceangraphic Inst., Woods Hols, MAD 2543, USA; Employment History: Assistant Scientist, Univ. Paris; GuestInvestigator, Woods Hole Oceanographic Inst.; Academic History: Univ. Rouen,M.Sc, 1969; Univ. Paris, Ph.D. 1972; Society Affiliations: Geol. Soc. France, RegionalAss. Paris Basin Geologists, Subcommission on Paleogene Strat.

AMIN A. AWADAssistant Professor of Soil Mechanics, Univ. Al Fateh, Tripoli; Address: Faculty ofEng., P.O.Box 1098, Tripoli, SPLAJ; Employment History: Staff member, Faculty ofEng., Assuit Univ., Egypt; Academic History: Budapest Univ., Ph.D. (Soil Mechanics)1968.

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SYAMADAS BANERJEEGeologist, Dept. Gcol. Researche's and Mining, Industrial Research Centre, Tripoli;Address: Ind. Res. Centre, P.O.Box 3633. Tripoli, SPLAJ; Employment History:19i2-1970 and 1973-1974 Senior Geologist, Geol. Surv. India; 1970-1972Post-Graduate Student and Teaching Assistant, Univ. Western Ontario, Canada; since1975 in present position; Academic History: Calcutta Univ., M.Sc. 1951; Univ.Western Ontario, M.Sc. 1972; Society Affiliations: Geol Mining and Metallurgical Soc.India, Earth Sci. Soc. Libya.

F. T. BARRManager, Geological Evaluation. Houston Oil and Minerals; Address: 1212 Main St.,Houston. Texas 77002, USA; Employment History: nine years spent with Oasis OilCompany of Libya as head of the Geological Laboratory, and several years working inpetroleum exploration in Southeast Asia and in the USA: Academic History: Univ. ofCalifornia (Berkeley). B.A. and M.A.. Univ. of London. Ph.D.; Joint auther (with A.A. Weegar) of Stratigraphic Nomenclature of the Sirte Basin, Libya, and Editor ofGeology and Archaeology of Northern Cyrcnaica, Libya.

WALTER M. BAUSCHProfessor for Mineralogy-Petrography, Institut fur Geologie und Mineralogie, Univ.Erlangen-Nurnberg, Fed. Rep. Germany; Address: Inst. fur Geol. und Min.,Schlossgarten 5, D-8520 Erlangen, Fed. Rep. Germany; Employment History:1958-1961 short jobs in industry, mainly petroleum companies; 1961-1963 Scholarshipat «Deusche Forschungsgemeinschaft; 1963 to present, with Mineralogical Institute,Univ. Erlangen-Nurnberg except 1973-1976, Professor, Dept. Geol. and Geophys.Engin., Faculty of Petroleum and Mining Engin., Univ. Al Fateh, Tripoli, SPLAJ;Academic History: Universities of Erlangen-Nurnberg and Claustahl-Zellerfeld, B.Sc.1956, M.Sc. 1958, Ph.D. 1961, Dr. habil; Society Affiliations: Deutsche GeologischeGesellschaft, Geologische Vereinigung, Deutsche Mineraloische Gesellschaft, Int.Asso. Sedimentologists, Earth Sci. Soc. Libya.

ABDEL R. 1. BAYOUMIProfessor of Geophysics, Cairo Univ.; Address: Geol. Dept., Faculty of Science, CairoUniv., Giza, Egypt; Employment History: B.Sc; Univ. of California (Berkeley), M.Sc.(Seismology); Stanford Univ., California, Ph.D.

MOHAMED N. BKLAII)Head, Dept. Geological and Geophysical Engineering, Faculty of Petroleum andMining Hngin. Univ. Al Fateh, Tripoli; Address: P.O. Box 6432, Tripoli, SPLAJ;Employment History: in present position since 1977; Academic History: Univ. AlFateh,"B.Sc. 1966; London Univ.. M.Sc. 1971; Bristol Univ. UK.. PH.D. 1977; SocietyAffiliations: AAPG. Earth Sci. Soc. Libya.

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EMILIO BELLINIChief Paleontologist, Paleontological Lab., AG1P Attivita Mincraria, Italy; Address:AGIP, AMI-SGEL-Paleontologia, 20097-S.Donato Milanese, Milano, Italy;Employment History: 1955-1959 micropaleontologist, SOMICEM and AGIP, CentralItaly; 1959-1964 geologist and micropaleontologist, AGIP in Sudan and Libya (workin Easten Cyrenaica); 1964-1968 head of AGIP micropal, and strat. foreign studies,and 1969 to present, chief paleontologist, AGIP, Italy; 1975 in charge of AGIPgeological survey Kufra Basin; Academic History: Modena Univ. Italy, Dr. rer. nat.,1953.

ANTHONY C. BENFIELDPrincipal Scientific Officer, Yorks and E. Midlands Field Unit, Geological Survey ofGreat Britain; Address: Institute of Geological Sciences, Ring Road Halton, Leeds 15,Yorkshire, U.K.; Employment History: 1963-1966 Research Demonstrator, Univ.College of Swansea, Wales; 1966 to present, Institute of Geological Sciences, firstlywith the Hydrogeological Dept. during which period he worked in Libya for some time,then with the field survey team; 1976-77 seconded to National Coal Board; AcademicHistory: Edinburg Univ., B.Sc; postgraduate studies in the Netherlands and at theUniv. "of Reading; Society Affiliations: Geol. Soc. London, Geol. Ass., Yorks Geol.Soc, Quaternary Research Ass.

WILLIAM A. BERGGRENSenior Scientist, Woods Hole Occanographic Institution, and Professor of Geology,Brown Univ.; Address: Dept. Geol. and Geophysics, Woods Hole Oceanographic Inst.,Woods Hole, Mass. 02543, USA; Employment History: 1962-1965Micropaleontologist, Oasis Oil Co., Tripoli, Libya; 1966 to present, Research Scientistat Woods Hole Oceanographic Inst.; 1968 to present, Professor of Geol., Brown Univ.Rhode Island; Society Affiliations: GSA (fellow), Geol. Soc. Switzerland, AAPG,Paleontological Soc., Pal. Research Inst., Sigma Xi.

DAVID J. BURDONConsulting Hydrogeologist; Director of Minerex Ltd.; advisor on groundwater to theGeol. Surv. of Ireland; Address: Rathclare House, Buttevant, Co. Cork, Ireland;Employment History: 1938-1947, Geologist-Surveyor, Kolar Gold Fields, MysoreState; 1949-1952, Assistant Water Engineer (Geologist), Colonial Service, Cyprus;1952-1974, Hydrogeologist, FAO of UN, Damascus to 1960, Athens to 1963 Cairo to1964, Rome FAO HO to 1974; 1974 to present, Consulting Hydrogeologist;Academic History: National Univ. of Ireland, B.E. (Civil) and B.Sc. 1935, M.Sc. 1949,D.Sc. (Hydrogeology) 1963; Univ. of London, Ph.D. (Geology), 1949, DIC.(Geophysics in Geology) 1949; Camborne School of Mines, Cornwall, A.C.S.M., 1937;Society Affiliations: Geol. Soc. London (fellow), Inst. Mining & Metallurgy London,Inst. Water Engin. & Scientist London, Soc. Econ. Geologists USA., Am. Geophys.Union, Am. Water Res. Ass., Geol. Soc. Italy, Irish Group Int. Ass. Hydrogeologists(President), Irish-Arab Soc.

DETLEF BUSCHELecturer, Univ. of Wurzburg, Fed. Rep. Germany; Address: Geographisches Inst.,Univ. Wurtzburg, Am Hubland, 8700 Wurtzburg, Fed. Rep. Germany; EmploymentHistory: 1972-1973, Research Assistant, Free Univ. of Berlin; 1973 to present,Lecturer, Univ. of Wurtzburg; Academic History: Free Univ. of Berlin and MinnesotaState Univ., (Staatsexamen) (M.A. equiv.); Free Univ. of Berlin, Ph.D., 1972; SocietyAffiliations: German Geomorphological Work-Group, Geographische GesellschaftWurtzburg.

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MABROUK T. BUSREWILchairman. Geology Dept., Univ. Al Fateh, Tripoli; Address: Geology Dept., Faculty ofScience, Univ. Al Fateh, P.O. Box 13258, Tripoli, SPI-AJ; Employment History:1974-1976 Lecturer, 1976 to present Assistant Professor, Univ. Al Fateh; AcademicHistory: Univ. of Libya, B.Sc. 1965; Manchester Univ., M.Sc. 1970, Ph.D. 1974.Society Affiliations: Earth Sci. Soc. Libya.

L_

PETR CEPEKGeological Consultant, Strojexport-Geoindustria Czechoslovakia, geological mappingand editor of Hammada El Hamra regional map, for Industrial Research CentreSPLAJ; Address: Faculty of Science, Charles Univ., Albertov 6, 12843 Praha 2,Czechoslovakia; and Stojexport, P.O. Box 2962, Tripoli, SPLAJ; EmploymentHistory: 1958-1960 Hydrogeologist, Prague; 1960-1977 Assistant and since 1963Assistant Professor, Charles Univ. Prague; mapping experience in CentralAsia/Mongolia and fades studies in the North Sea; 1977 to present, GeologicalMapping in SPLAJ; Academic History: Charles Univ., Prague, B.Sc. 1958, R.N. Dr.1964, C. Sc. 1965; Society Affiliations: Czech. Ass. Geologists and Mineralogists.

JOSEPH CHALOUPSKYGeological Consultant, Strojexport-Geoindustria Czechoslovakia, geological mappingand editor of a Hammada El Hamra regional map, for Industrial Research CentreSPLAJ, on loan from Geological Survey of Czechoslovakia; Address: Geol. Surv.Czechoslovakia, Prag, Malostranska nam. 19; and Strojexport-Geoindustria, P.O. Box2962, Tripoli, SPLAJ; Employment History: 1956 to present, Geol. Surv.Czechoslovakia, including 1961-1969 seasonal geol. mapping in CaledonianMetamorphic complexes, Norway, 1966-1968 Lecturer at Baghdad Univ. Iraq,1975-1976 Strat. and Structural Studies in Cuba, and 1977 to present, mapping inSPLAJ; Academic History:Charles Univ., Prague, B.Sc. 1956, R.N.Dr. and C.Sc.1964; Society Affiliations: Czechoslovak Int. Norwegian Associations of Geologistsand Mineralogists, Committee Int. Caledonian Project (member), head of DeepStructure Project.

DANIEL D. CLARK-LOWESResearch Student, Imperial College, London Univ., currently engaged upon researchon the Murzuk Basin, Fezzan, for a Ph.D. thesis; Research Assistant, Univ. Al Fateh,Tripoli; Address: Geol. Dept., Faculty of Science, Univ. Al Fateh, P.O. Box 13258,Tripoli, SPLAJ; Employment History: 1974-1977 Geologist, Shell InternationalPetroleum Co.; 1977 to present, Research Student, Imperial College; GeologicalConsultant, Marengo Ltd. Tripoli, 1977 and Research Assistant, Univ. Al Fateh,Tripoli, 1978; Academic History: Cambridge University, UK, B.A. 1974, M.A. 1977;Society Affiliations: Geol. Soc. London, Geol. Ass. London, SEPM.

HAROLD J. CLIFFORDChief Geologist, Arabian Gulf Exploration Company, SPLAJ; Address: P.O. Box 263Benghazi, SPLAJ; Employment History: 21 years with Shell Oil Co., USA; two andhalf years with AGECO, Benghazi; Academic History: Univ. of Utah, B.S.; Graduatestudies at Univ. of California, Berkeley; Society Affilations: Earth Sci. Soc. Libya,AAPG.

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F. H. CRAMERDirector, Institute de Investigations palinologicas, Leon;Address: Apartado 244,Leon, Spain; Employment History: 1964-1966 Research Scientist Pan AmericanPetroleum Corporation; 1966-1974 Professor of Geology, Florida State Univ. U.S.A.;1975 - present Director, Instituto de Investigaciones Palinologicas, Leon; AcademicHistory: University of Leiden, Doctor of science, 1964; Society Affiliations: A.A.S.P.(Founding member), Asociacion de Palinologos de Leugna Espanola (Foundingmember and President).

MAGHAWRY S. DIABAssistant Professor, Desert Institute, Mataria, Cairo; Address: Desert Institute,Mataria, Cairo, Egypt; Employment History: Desert Institute, Cairo, 196i to present,research associate to 1972, researcher to 1978, appointed Assistant Prof. 1978; visitingLecturer, Univ. Al Fateh, Tripoli, 1974-1977; Academic History: Ph.D. Egypt.

J. SLADE DINGMANGeologist, Geoexplorers Inc., Denver;Colorado 80222, U.S.A.

Address: 5701 E. Evans Ave., Denver,

ABDOULRHMAN K. DOUGHR1Head of Evaluation and Development Section, Dept. of Geol. Researches and Mining,Industrial Research Centre, Tripoli, SPLAJ; Address: P.O. Box 3633, Tripoli, SPLAJ;Employment History: 1973 to present, Industrial Research Centre; Academic History:Al Fateh Univ., Tripoli, B.Sc; Ohio Univ., USA, M.Sc; Society Affiliations: Soc.Hxpl. Gcophysicists.

LASZLO DUBAYSenior staff member of Italconsult Sp. A, Rome Italy; Address: Italconsult Sp.A, ViaGiorgione. 163 Roma, Italy; Employment History: 1953-1963 petroleum explorationgeologist, Hungarian State Oil Enterprise; 1963-1964 post grad. studies at «ScuolaSuperiore Sugli Idrocarburi»; 196:5 to present, Italconsult, working as hydrogeologist inmuch of Middle East, incl. SPLAJ; Academic History: Eotvos Lorand Univ., Budapest,Hungary, B.Sc. 1953, Doctor of Natural Sciences 1961.

W. M. EDMUNDSPrincipal Scientific Officer, Institute of Geological Sciences, Hydrogeology division;Address: Inst. Geological Sciences, Maclean Bldg, Crowmarsh Gifford Wallingford,Oxon 0X10 8BB, G.B.; Employment History: 1966 to present, Institute of GeologicalSciences, research indo geochemistry of groundwaters, set up hydrochemical Lab.,1967-1968 and 1972-1974 member IGS team investigating grounu water resources inLibya, since 1976 joint project leader into geothermal potential of UK. and elsewhere;Academic History: Liverpool Univ., B.Sc. 1963, Ph.D. 1968; Chairman InternationalGroup on Water-Rock interaction in Sedimentary Rocks of the Int. Ass. Geochemistryand Cosmochemistry.

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ESSAM A. M. EISSAAssociate Professor, Physics Dept., AJ Fateh Univ., Tripoli; Address: Faculty ofScience, Al Fateh Univ., P.O. Box 6-J6, Tripoli SPLAJ; Employment History:1960-197-5 research scientist, then Head of Reactor and Neutron Physics Dept.,Atomic Energy Establishment, Egypt; 1976 to present Al Fateh Univ.; AcademicHistory: Cairo Univ., B.Sc. 1960; Czechoslovak Academy of Sciences, NuclearResearch Inst., Ph.D. 1968; Society Affiliations: Mathematical Physical Soc. of Egypt,Board member of the Nuclear Science and its Application Soc. of Egypt.

ALI EL ARNAUTIAssociate Professor, Univ. Gar Younis, Benghazi, SPLAJ; Address: Geol.Faculty of Science, Univ. Gar Younis, P.O. Box 9480, Benghazi, SPLAJ.

Dept..

SALAH I. EL-BATROLKHAssistant Prof., Facultyof Petro. and Mining Eng., Univ. Al Fateh; Address: P.O. Box14464, Bab Bin Ghashir, Tripoli. SPLAJ; Employment History: 1963-1969 Teacher,El-Beida Sec. School, Gebel Al Akhdar; since 1975 Lecturer and Assistant Prof., AlFateh Univ.; Academic History: Cairo Univ., B.Sc. 1963; Newcastle Univ., England,M.Sc. 1972; Glasgow Univ., Scotland. Ph.D. (Applied Geophysics) 1975; SocietyAffiliations: Soc. Expl. Geophysicists, USA.

HASSAN A. EL-ETRAssociate Professor, Ain Shams University, Cairo; Address: Geol. Dept., Faculty ofScience, Ain Shams Univ., Cairo, Egypt; Employment History: 1960-1961Demonstrator, Geol. Dept., Cairo Univ.; 1967-1974 Lecturer, Ain Shams Univ.,Cairo, on deputation to Al Fateh Univ. Tripoli 1970-1974; 1974 to present AssociateProf., Ain Shams Univ. and 1976-1977 part time research affiliate, Egypt Geol. Surv.Cairo; Academic History: Cairo Univ., B.Sc. 1959; Missouri School of Mines andMetallurgy, Univ. Missouri-Rolla, M.Sc. 1963, Ph.D. 1967; Society Affiliations: GSA,AAPG, Geol. Soc. Egypt, Egyptian Science Foundation.

AHMED S. EL HAWATAssistant Professor, Geol. Dept., Gar Younis Univ., Benghazi, SPLAJ; Address: Geol.Dept., Faculty of Sci., P.O. Box 9490, Gar Younis Univ., Benghazi, SPLAJ;Employment History: 1965-1966 libyan Ministry of Petroleum; 1966-1975 Al FatehUniv., SPLAJ; 1975 to present Gar Younis Univ. Benghazi; Academic History: AinShams Univ. Cairo, B.Sc. 1965; Stanford Univ., Calif. USA, M.Sc. 1970; LondonUniv. UK. Ph.D. 1975; Imperial College, UK, D.I.C. 1975; Society Affiliations:S.E.P.M., Int. Ass. Scdimentologists, Earth Sci. Soc. Libya.

BAHLUL A. ELIAGOUBIVice Dean, Faculty of Science, Univ. Al Fateh, Tripoli; Address: P.O. Box 13555,Tripoli, SPLAJ; Employment History: 1969-1976 Staff member, Geol. Dept.,1976-1978 Chairman, Geol. Dept., Faculty of Science, Univ. Al Fateh, Tripoli; 1978appointed Vice Dean; Academic History: Faculty of Science, Tripoli, B.Sc. 1969;Univ. Idaho, USA, MSc. 1972, Ph.D. 1975; Society Affiliations: SEPM, AAPG, EarthSci. Soc. Libya.

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SAAD I. EL KHAWALKAAssistant Professor, Faculty of Engineering, Univ. Al Fateh, Tripoli; Address: CivilEng. Dept., Faculty of Eng., P.O. Box 1098, Univ. Al Fateh, Tripoli, SPLAJ;Employment History: Since 1965 Lecturer and Assistant Professor, Faculty of Eng.,Alexandria, Egypt; Academic History: Moscow, Ph.D. 1965.

ISMAIL M. ELRAMLYUnited Nations, FAO, Senior Hydrogeologist, Secretariat Dams and Water Resources,Tripoli; Address: CIO UNDP, P.O. Box358, Tripoli, SPLAJ; Employment History:1953-1957 Petroleum Geologist, Sahara Petr. Co., Alexandria, Egypt; 1957-1972,groundwater research in Egypt and West Germany in post including Senior ResearchHydrogeologist at the Desert Research Inst. Cairo, General Desert Dev. Authority,Cairo, Aswan Regional Planning Project, Egypt, and Speers Planning Bureau,Frankfurt; 1972 to present, FAO consultant positions in India, Chad, Saudi Arabia(Senior Hydrogeologist), and Libya, present position; Academic History: Cairo Univ.,B.Sc. 1953; UNESCO Diploma in groundwater resources development, 1958; StateUniv. Iowa, Ph.D. 1962; UNESCO Diploma in water resources planning andmanagement (Univ. Prague) 1969;n Society Affiliations: Egyptian Science SyndicateCairo, Geol. Soc. Cairo, Arab Mining and Petroleum Ass. Cairo, National Water WellAss. USA.

KARIMA M. EL SHKR1EFResearch Assistant, Physics Dept., Faculty of Science, University of Al-Fateh, Tripoli;Address: Faculty of Science, University of Al-Fateh, P.O. Box 13555, Tripoli, SPLAJ;Employment History: in present position since 1977; Academic History: Univ. AlFateh, B.Sc.

ASHOUR Y. EL-ZOUKIAssistant Professor, Gcol. Dept., Gar Younis Univ., Benghazi, SPLAJ; Address: Geol.Dept., Faculty of Sci., Univ. of Gar Younis. P.O. Box 9480, Benghazi, SPLAJ;Employment History: Univ. Al Fateh, Geol. Dept., Demonstrator 1967-1968,Assistant Lecturer 1971-1972; Univ. Gar Younis, Geol. Dept., Lecturer 1976-1977,Assistant Prof, from 1977; Academic History: Univ. Al Fateh, B.Sc. 1967; Univ.Kansas - Lawrence USA, M.Sc. 1971; Univ. of Bristol, Ph.D. 1976; SocietyAffiliations: SEPM, Int. Ass. Sedimentologists.

JURGEN ERDMANNPostgraduate Student, Geologisches Institut der Universitaet, Univ. of Karlsruhe;Address: Kaiserstr. 12, D-7500 Karlsruhe 1, Fed. Rep. Germany; EmploymentHistory: 1973-1974 Hydrologist post, Water Authorities, Baden Wurttemberg State,Germany; 1976-1977 Engineering Geologist post in Austria followed by GeologicalConsultant (Structural Geology) post, Marengo Ltd. (for National Oil Corp. of Libya);Academic History: Univ. of Karlsruhe, B.Sc. 1976, M.Sc. 1978; Society Affiliations:Oberrheinischer Geologische Gescllschaft (Karlsruhe), Earth Sci. Soc. Libya.

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A LI N. FATMIDirector, Geological Survey of Pakistan, Quctta, and Associate Professor, Al FatehUniv. Tripoli; Address: Geol. Dept., Univ. Al Fateh, P.O. Box 13258, Tripoli, SPLAJ;Employment History: Geol. Surv. Pakistan up to 197-5; 197-5 to present at Al Fateh;Academic History: Univ. of Wales, B.Sc. and Ph.D.

FERRY FEDIUKAssociate Professor, Petrology Dcpt. Charles Univ., Prague, Czechoslovakia; Address:Faculty of Science, Charles Univ., Albertov 6, 12843 Praha 2, Czechoslovakia;Employment History: 1964-67 Vice Dean, Faculty of Science, Charles Univ., MemberOrganizing Committee 23rd Int. Geol. Congr., in 1965, organizer of Int. Symp. onVolcanics of Bohemian Massif; 1967 to present, Assoc. Prof. Charles Univ.; visitinggeologist Vietnam, Norwegian Geol. Surv. and Paris Univ.; Academic History: CharlesUniv., B.Sc. 1951, R.N. Dr. 1952, C.Sc. 1958, Dr. habil. 1963. ParticipantUNESCO'Opliolites' Geol. Exped. Western Pacific 1976.

EDWARD P. FISKConsulting Hydrologist; Ph.D. candidate, Hydrology, Utah State Univ., USA;Address: 1026 North 600 East, Logan Utah 84321, USA; Employment History:1949-1959 Consulting Petroleum Geologist, and Petroleum Engineer; 1959-1966Consulting Hydrologist and Vice President, C.E. Jacob and Associates; 1968-1971Chief Geohydrologist, Occidental of Libya, Inc.; 1971-1977 Chief Geohydrologist,Frank E. Basil, Inc.; 1977 to present, Consulting Geologist; Academic History:California Inst. Technology, B.S. 1949; Univ, South California, M.S. 1967; Utah StateUniv., Ph.D. candidate at present; Society Affiliations: Ass. Engineering Geologists.

REINHARD FORSTERCurator, Bayer, Staatsammlung fur Paleontologic und Historische Geologie, Fed. Rep.Germany; Address: Richard-Wagner-Str. 10/11, D-8000 Munchen 2, Fed. Rep.Germany; Employment History: 1964-1970 Junior Lecturer, Inst. fur Palaontologieund Hist. Geologie, Munchen; 1970 to present, Curator, Bayer; Academic History:Gottingen, Vienna, and Munchen Universities; Dipl-Geol. 1961; Dr. rer. nat. 1964;Society Affiliations: Palaontologische Gesellschaft, Geologische Vereinigung.

PAUL D. FULLAGARProfessor of Geology, Univ. North Carolina, USA; Address: Univ. North Carolina,Chapel Hill, N.C. 27514, USA; Employment History: 1963-1967 Assistant Prof.Geol., Old Dominion College, Norfolk, Virginia; 1967 to present, Assistant Prof, to1969, Associate Prof, to 1973, and since 1973 Professor at Univ. North Carolina;Academic History: Columbia Univ., B.S. 1960; Univ. of Illinois, Ph.D. 1963; SocietyAffiliations: Am. Ass. Advancement of Science, Am. Ass. Univ. Profs., Am. Geophys.Union, Geochem. Soc, GSA, Int. Ass. Geochem. and Cosmochemistry, Nat. Ass.Geol. Teachers, Sigma Xi.

JEAN M. GAILLARDLecturer, Laboratoire de Biologic des Invertebres marins et de Malacologie, MuseumNational d'Histoire Naturelle, Paris; Address: Mus. Nat. d'Histoire Naturelle, 75005Paris, France; Academic History: Docteur de l'Universite de Paris; Society Affiliations:Societe Francaise de Malacologie (Secretaire), l'Unitas Malcologica (President).

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WAHID GAZIRYLecturer, Univ. Gar Younis, Benghazi, SPLAJ; Address: Geol. Dept., Faculty ofScience, Univ. Gar Younis, P.O. Box 9480, Benghazi, SPLAJ.

SALEM M. GHELLALILecturer, Geol. Dept., Faculty of Science, Univ. AI-Fateh, Tripoli; Address: Geol.Dept., P.O. Box 13258, Univ. Al Fateh, Tripoli, SPLAJ; Employment History: 1964Geologist, Oasis Oil Co., Tripoli; 1965-1970 Teaching Assistant, Geol. Dept., Tripoli;1968-1969 representative of Libyan Arab Jamahiriya to the U.N. ad hoc committee onstudy of sea bed and ocean floor beyond the national jurisdiction; 1970-1971 PresidentSupervisory Committee for Water and Soil Resources for Hydroagriculturedevelopment in Libya, Min. Agric; 1971 to present Lecturer in geology; AcademicHistory: Univ. Al Fateh, B.Sc. 1964; Columbia Univ., New York, M.A. 1970;Manchester Univ., Ph.D. 1977; Society Affiliations: Earth Sci. Soc. Libya.

ASOK K. GHOSHHydrogeologist, Secretariat of Dams and Water Resourcec, Benghazi Branch, SPLAJ;Address: P.O. Box 1301, Benghazi, SPLAJ; Employment History: 1966-1968.Assistant Engineer Mining and Allied Machinery Corp. Ltd., India; 1971-1972Assistant Prof., Civil Engineering, Agric. Univ., Patnagar, India; 1972-1975 Lecturer,Agric. Engin. Dept., Nadia, India; since 1975 in SPLAJ; Academic History: Univ.Calcutta, India, B. Eng. 1965; Univ. Illinois, USA, M.Sc. 1969, Ph.D. 1971.

MOHAMED A. GHUMAAssistant Professor, Geol. Dept., Faculty of Science, Al Fateh Univ., Tripoli; Address:Al Fateh Univ., P.O. Box 13258, Tripoli, SPLAJ; Employment History: Short termpost with American Overseas Petr. Co. in Libya, 1963-1967, and teaching assistant,Univ. Al Fateh, 1967; 1976 to present staff member, then Assistant Professor, Geol.Dept., Faculty of Sci., Al Fateh Univ.; Academic History: Faculty of Science, Tripoli,B.Sc. 1967; Univ. Kansas, M.Sc. 1971; Rice Univ., Ph.D. 1975.

GUS H. GOUDARZIEconomic Geologist, United States Geological Survey; Address: U.S.G.S., 920National Center, Reston, Virginia 22092, USA; Employment History: Mining andGeological Engineer, Anaconda Co. until 1951; 1951 to present, US Geol. Surv. doinggeological reconnaissance and mineral investigations in Ghana, Suadi Arabia, Libya(1954-1962), U.S., and Brazil; since 1971 U.S.G.S. HQ, Washington; while in LibyaChief minerals investigation program advisor; Academic History: Montana College ofMineral Science and Technology, B.S. (Mining Engineering) and M.S. (GeologicalEngineering); Society Affiliations: Am. Inst. Mining Metallurgical and PetroleumEngineers, GSA (fellow), Geol. Soc. Washington, Ass. Prof. Geol. Scientists. Authoror coauthor of «Geology and Mineral Resources of Libya», «Geologic Map of Libya»,«Stratigraphic and Tectonic Framework of Libya», «Geology of the Shatti Valley IronDeposits, Libya», and «Salt deposits-Pisida, Marada, Idri, Libya».

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JORG W. GRUNERTResearch Assistant. Geographisches Institut der Univcrsitat Wurzburg, Fed. Rep.Germany; Address: Hauptstr. 139, 8711 Mainstockheim, Fed. Rep. Germany;Employment History: 1970-1972 Research Assistant, Technical Univ. Aachen; 1972to present, Research Assistant, Univ. of Wurzburg; Academic History: Free Univ. ofBerlin, M.Sc. 1970; doctorate 1974 on valley evolution in the Tibesti Mountains;Society Affiliations: Deutscher Arbeitskrcis fur Geomorphologie.

ALAIN GUERREHydrogeologist, UNFAO, attached to Secretariat of Dams and Water Resources,Benghazi Branch, SPLAJ; Address: P.O. Box 1301, Benghazi, SPLAJ; EmploymentHistory: 1964-1966 Centre National de la Recherche Scientifiquc (France), Ministercdes Resources Hydrauliques (Lebanon); 1966-1970 Expert of the French BilateralTechnical Cooperation; since 1970, expert with FAO; Academic History: Licence deDoctorat-Geology and Geophys, 1963; 3eme cycle-Hydrogeology ore deposits, 1964;Doctoral de Specialite Hydrogeology, 1969; Society Affiliations: Int. Ass.Hydrogeologists, Union Francaise des Geologues.

HORST HAGEDORNProfessor of Geography and Head of Geol. Dept., Univ. of Wurzburg, Fed. Rep.Germany; Address: Geographisches Inst., Univ. Wurzburg, Am Hubland. 8700Wurzburg, Fed. Rep. Germany; Employment History: 1960-1970 Research Assistant,then from 1969 Professor, Free Univ. of Berlin; J970-I97I Professor, School ofTechnology, (RUTH), Aachen; 1971 to present, Professor, Univ. of Wurzburg;Academic History: Univ. of Gottingen, B.Sc. and Ph.D.; Free Univ. of Berlin, Drhabil; Society Affiliations: Earth Science Soc. Libya, Gesellschaft fur Erdkunda zuBerlin, Libya, Society of Oriental Studies (London), I.G.U.

JAMES M. HALLProfessor, Geol. Dept., Dalhousie Univ., Canada; Address: Dalhousie Univ., Halifax,Nova Scotia B3H 3J?, Canada; Employment History: 1961-1963 Research Assistant,Dept. Applied Geophysics, Imperial College, London; 1963-1966 Lecturer, Univ. ofIfe, Nigeria; 1966-1970 Lecturer, Liverpool Univ., UK; since 1970 at Dalhousie;Geophysical Exped. to Libya 1970; participant 1973-1974 Glomar Challenger drillingcruises; Academic History: Univ. of Wales, B.Sc, 1957; Imperial College, Univ. ofLondon, Ph.D., 1961.

EVA HANZLIKOVAChief of Micropaleontology Lab., Prague; Address: Praha 4, Jalodvorska 2889,Czechoslovakia.

HELMUT HAUSLERPostgraduate Student, Geologisches Institut der Universitaet, Univ. of Karlsruhe;Address: Kaiserstr. 12, D-7'500 Karlsruhe 1, Fed. Rep. Germany; EmploymentHistory: 197i-1976 Hydrogeologist post, Water Authorities, Baden-WurttembergState, Germany; 1976-1977 Consultant Geologist, Marengo Ltd. (for National OilCorp. of Libya); Academic History: Univ. of Karlsruhe, B.Sc. 1976.

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JEAN DE HEINZELINProfessor, Univ. Ghent, and Professor part-time at Univ. Brussels, Belgium; Address:Gcologische Institut R.U.G., Krijgslaan 271, B9000 Gent, Belgium; EmploymentHistory: 1945-1960 attached to Royal Inst. Natural Sciences, Brussels; since 1960 inpresent positions; field work and research on Paleontology, Paleoanthropology,Quaternary Geology and Prehistory in Libya, Zaire, Kenya, Ethiopia, Sudan, Egypt,Syria, Lebanon, Europe and USA.

FRIEDRICH-FRANZ HELMDACHAssistant Professor, Institute for Palaeontology, Free Univ. of Berlin; Address: FreeUniv. of Berlin, D-1000 Berlin 33, Schwendenerstr. 8; Employment History:1966-1971, Assistant and Cooperator, Palaeontological Institute, Berlin; since 1971,Assistant Prf. at the Free Univ.; Academic History: 1958-1966 science studies at theFree Univ. of Berlin, Diploma in Geol., 1966 Dr. rer. nat. (Palaeontology) 1975, Dr.habil (Palaeontology); Society Affiliations: Palaontologische Gesellschaft, SEPM.

IBRAHIM H. HIMIDAProfessor of Hydrogeology. and Head of Hydrogeological Dept., Desert Inst., Mataria,Cairo; Address: Desert Inst.. Mataria, Cairo, Egypt; Employment History: Assoc.Prof. Hydrogeology, Geol. Dept. Kuwait Univ.; Desert Inst., Cairo; Academic History:Alexandria Univ., Egypt, B.Sc. 1957; Moscow Geol. Surv. Inst., Hydrogeology Dept..Ph.D. 1964; Delft Diploma in Engineering Hydrology, Delft, Netherlands, 1971.

MILOJE ILICHProfessor of Geology, Univ. of Belgrade, Yugoslavia; Address: Faculty of Mining andGeology, Univ. of Belgrade, 11 000 Belgrade, Djusina 7, Yugoslavia; EmploymentHistory: 1961-1967 Institute for Geological and Geophysical Research, Belgrade.1967 to present, Professor of Geol., Univ. of Belgrade, and Consulting Geologist;visiting Prof. Colorado School of Mines USA, 1970-1971, and Faculty of Petroleumand Mining Engineering, Univ. Al Fateh, 1977.

DIETER JAKELProfessor, Physical Geography, Free Univ. Berlin, Fed. Rep. Germany; Address:Institut fur Physischc Gcographie, Grunewaldstr. 35, D-1000 Berlin 41, Fed. Rep.Germany; Employment History: 1964-1967 researcher at the Free Univ. Berlin's fieldstation in Bardai, Tibesti; Free Univ. Berlin, 1967-1970, Lecturer, 1970-1972Akademischer Rat, 1972-1975 and 1978 to present, Administrative Director, Inst.Physical Geogr.; Academic History: Free Univ. Berlin, Staatsexamen 1964, Ph.D.1969; Society Affiliations: Gesellschaft fur Erdkunde zu Berlin, BerlinerGeographischen Abhandlungen (Editor).

OMAR A. JARROUDHydrogeologist, Secretariat of Dams and Water Resources, Tripoli, SPLAJ; Address:Secretariat of Dams and Water Res., P.O. Box 5332, Tripoli, SPLAJ; EmploymentHistory: 1972-1974 Field Hydrologist, General Water Authority, Tripoli; 1977 topresent, Hydrogeologist Secretariat Dams and Water Res.; Academic History: Univ.Al Fateh, B.Sc. (Agric) 1972; Univ. Arizona, Tuscon, M.Sc. 1977; Society Affiliations:Am. Water Resources Ass., Am. Geophys. Union.

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LADISLAV JURAKGeological Consultant and Chief Geologist, Geoindustria Jihlava, Czechoslovakia;Address: Geoindustria Jihlava, Malinovskehe 78, Jihlava, Czechoslovakia;Employment History: since 196i, Geoindustria Prague, field geologist, then chiefgeologist, specialist in Fluorite, Baryte, and Pb. Zn prospection; geological mapping inSPLAJ, 1972-1973 Al Bayda and Ras Ideir, senior geologist; 1976-1977 JabalHasawnah, editor of sheet; Academic History: graduated Charles Univ. Prague, 19">4.

RASHAD M. KEBEASYAssistant Professor Geophysics, Al Fateh Univ. Tripoli; Address: Geology Dept.,Faculty of Science, Al Fateh Univ., P.O. Box 13258, Tripoli, SPLAJ; EmploymentHistory: 1963-1975, Assistant Researcher and then Researcher, Geophysical Dept.,Hlewan Observatory, Helwan, Egypt; 1975 to present, Al Fateh Univ.; AcademicHistory: Assiout Univ., Egypt, B.Sc. 1963; Cairo Univ., M.Sc. 1968; Tokyo Univ.D.Sc. 1971; Society Affiliations: Geophys. Soc. Egypt, on Committee on RecentCrustal Movement, IUGG.

MOHAMED Y. KHANHead of Benghazi Plain Project, Secretariat of Dams and Water Resources, BenghaziBranch, SPLAJ; Address: P.O. Box 1301. Benghazi, SPLJ; Employment History:1956-1974 Geol. Surv. Pakistan, Assistant Geologist Through to Director (after 1973);since 1974 geologist with Sec. Dams and Water Res. SPLAJ; Academic History:Aligarh Univ., India, M.Sc. 1954; U.S. Geol. Surv., photogeology Certificate of Merit,1960; Australian National Univ., Ph.D. 1973.

RIYAD H. EL KHOUDARYAssistant Professor for Statigraphic Micropaleontology, Faculty of Petroleum andMining Engineering, Univ. Al Fateh, SPLAJ; Address: Univ. Al Fateh, P. O. Box10479 MS., Tripoli, SPLAJ; Employment History: 1968-1970 Assistant, Geol. Inst.Univ. Stuttgart, Germany; 1971-1972 Field Geologist, Hafner Co. (Engin. Geol.),Stuttgart; since 1972 Univ. Al Fateh; Academic History: Cairo Univ. Egypt, B.Sc,1974; Univ. Stuttgart, Diplom-Geologe, 1968, Dr. rer. nat. 1972; Society Affiliations:Earth Sci. Soc. Libya, Union of Arab Geologists.

JEAN M. KLERKXHead of Geology Section, Royal Museum for Central Africa, and Lecturer, Univ.Liege, Belgium; Address: Mus. Roy. de l'Afrique Centrale, B-1980 Tervuren,Belgium; Employment History: 1963-1975 research assistant, Univ. Liege; since 1975geologist at the Royal Museum for Central Africa; Academic History: Univ. Liege,Licencie en Sciences geologiques et mineralogiqucs, 1960, Docteur en Sciences geol. ctmin., 1968; Society Affiliations: Belgian Geol. Soc, Ass. des Geologues du Sud-Ouest.

CORNELIUS A. KOGBEProfessor and Head of Geol. Ahmadu Bello Univ., Nigeria; Address: Geol. Dept.,Ahamdu Bello Univ., Zaria, Nigeria; Employment History: Univ. Tokyo, visitor;visiting lecturer, Inst. Geol. and Paleontology, Technical Univ. Berlin; visitingLectureship and Professorship in Britain and France; Academic and field attivities inNigeria; Academic History: Univ. Ibadan, B.Sc. 1965; Univ. Lyon, France Dr. Sc. Nat.1968; Ecole National Superieur du Petrole et Moteur, Inst. Francais du Petrole,Diploma dTngenieur 1969; Project Leader UNESCO Project No 127, IGCprogramme, Continental Terminal of Africa.

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KARL-HEINRICH KRAFTFinrolled in M.S. Programme, Geologisches Institut der Universitaet, Univ. ofKarlsruhe; Address: Kaiscrstr. 12, D-75OO Karlsruhe 1, Fed. Rep. Germany;Employment History: 1975-1976 Assistant and Consultant Engineering Appointmentsin Germany and Austria; 1976-1977 Consultant Geologist, Marengo Ltd. (for NationalOil Corp. of Libya); Academic History: Univ. of Karlsruhe, B.Sc. 1976, M.Sc. 1978;Society Affiliations: Deutsche Geologische Gesellschaft, Geologische VereinigungOberrheinischer Geologischer Verein., Earch Sci. Soc. Libya.

JAN KRASONPresident, Geoexplorer Inc., Denver; Address: 5701 E.Evans Ave., Denver, Colorado80222, U.S.A.

ALFRED KRONERProfessor of Geology, Dpet. Geol. Sciences, Univ. of Mainz, Fed. Rep. Germany;Address: Institute fur Geowissenschaften, Universitat Mainz, Saarstr. 21, 6500 Mainz;Employment History: 1966-1976, Precambrian Research Unit on the Precambrian ofAfrica, Senior Research Fellow after 1969, and 1973-1975 Acting Director; 1977 topresent, Prof, of Geology at Mainz Univ.; Academic History: 1960-1965 TechnicalUniv. Clausthal-Zellerfeld, Univ. of Vienna, Technical Univ. Munich;Dcplom-Geologe (Munich) 1965; Ph.D. 1968; Society Affiliations: GSA, WestGerman Geologische Verein., Am. Geophys., Union, AGID, Geol. Soc. London,Coordinator for the CGMU Tectonic Map of Africa, Member of 5 1CCP Projects.

GIDEON V. KKUSEMANHydrogeological Consultant in agriculture and water resources; Address: Sportlaan44A, 6717 LB EDE, Netherlands; Employment History: 1962-1964 geologist,Ptroleum Dept., Turkish Geol. Surv.; 1964-1970 International Inst. Land Reclamationand Improvement, Wageningcn, Netherlands (1966-1967 posted to UNFAORomania); 1970 to present, one of a Netherlands pool of agricultural experts for int.cooperation, working with FAO in Marocco (1970-1973) and Libya (1973-1977),working on the Gefara-Gadames area with the Secretariat of Dams and WaterResources; 1977 to present, consultant, including work on Tripoli's water supply;Academic History: Utrecht Univ., Netherlands, Ph.D. 1962; Society Affiliations: RoyalGeological and Mining Soc. Netherlands, Int. Ass. Hydrogeologists.

JOHN C. LORENZResearch Student, Princeton Univ., USA, engaged on Ph.D. thesis; Address: Geol. andGeophys. Sci. Dept., Guyot Hall. Princeton Univ., Princeton, N.J. 08540; EmploymentHistory: 1972-1973 English teacher, Morocco; 1974-1977 U.S. Geol. Surv. geologist;1977 geological consultant, Marengo Ltd. Tripoli, SPLAJ; Academic History: ObcrlinCollege, USA, BA, 1972; Univ. S. Carolina. M.S. 1974; 1977 to present, research forPh.D. including Libyan Murzuk Basin studies; Society Affiliations: New Mexico Geol.Soc; Roswell Geol. Soc.

KHALED R. MAHMOUDFaculty member, Soil and Water Dept., Faculty of Agriculture, Univ. Al Fateh, Tripoli;Address: P.O. Box 13643, Tripoli, SPLAJ; Employment History: At Soil and WaterDept. since 1977; Academic History: Cairo Univ., B.Sc. 1969; Colorado State Univ.,M.S. 1973, Ph.D. 1977; Society Affiliations: Am. Soc. Agronomy (Soil Science).

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DHARAM VIR MALLICKProfessor of Civil Engineering, Univ. of Al Fateh, SPLAJ; Address: Civil EngineeringDept., Univ. A] Fateh, P.O. Box 1098, Tripoli, SPLAJ; Employment History:Assistant Engineer, Lecturer in civil engineering, then Senior Research Fellow inEngland; Assistant Professor, I1T Delhi; Univ. Al Fateh, Professor and Consultant instructures and earthquake engineering; Academic History: B. Tech. (Hons), P.G. Dip.,M.E. (Structures). Ph.D., M.I.E. (India), M.ISET, M. ASCE.

VISHNU D. MAMGAINGeologist, Micropaleontologist, Industrial Research Centre, Tripoli, on deputation fronGeol. Surv. India; Address: Dept. Geol. Researches and Mining, Ind. Res. Centre,P.O. Box 3633, Tripoli, SPLAJ; Employment History: 1960-1974 Senior Geologist(Micropal.), Geol. Surv. India; since 1975 in present position; Academic History:Lucknow Univ., India, M.Sc. 1959; Society Affiliations: Earth Sci. Soc. Libya, Geol.Soc. India (fellow).

DOMINIQUE PJ. MASSAPost in Exploration Dept. Compagnie Francaise des Petroles, Paris; Address: Expl.Dept., C.F.P., 6, Rue Jean Jacques Rousseau, Suresnes 921:50, France; EmploymentHistory: 1948-1952, Societe des Petroles D'AEF (Gabon); 19-52-19i3, NationalTurkish Company (M.T.A.); 1954-1956, compagnie Francaise des Petroles d'Algerie;1956-1961, Chief Geologist. Compagnie des Petroles Total Libye (C.P.T.L.);1962-1968, Exploration Mgr. C.F.P., Paris; 1968-1971, Expl. Mgr. C.F.P. Algerie;1971-1973, Expl. Dept. C.F.P. Paris; 1974-1977, Expl. Mgr. C.P.T.L. Tripoli, andinvolved in a joint venture with National Oil Corp. of Libya; 1977 to present, return toExpl. Dept. C.F.P. Paris; Academic History: Univ. of Lausanne, 1947, Univ. ofParis-Sorbonne, 1946-1948, graduated Licencie-es-Sciences; 1948-1949, EcoleNationale Superieure des Petroles, graduated Engineer-Geologist; Society Affiliations:Geol. Soc. France, AAPG, Earth Sci. Soc. Libya, Ass. Francaise des Techniciens duPetrole.

MOHAMED F. MEGERISIDirector Geological Mapping Division, Industrial Researc Centre, Tripoli, SPLAJ;Address: I.R.C., P.O. Box 3633, Tripoli, SPLAJ; Employment History: 1972 topresent, geologist with Ind. Res. Centre Tripoli; Academic History: Univ. Al Fateh,B.Sc. 1972; Ohio Univ. USA, M.Sc. 1976; Society Affiliations: Earth Sci. Soc. Libya.

AMIN A. MISSAIXATIAssociate Professor of Geology, Geology Department. Faculty of Science, Universityof Al Fateh, Tripoli; Address: P.O. Box 1325S, Tripoli, SPLAJ; Employment History:1972 to present, Univ. Al Fateh. Assistant Prof, to 1973, Chairman Geol. Dept. ta1974. Vice Dean, (acuity of Sci. to 1976. Society Affiliations: Earth Sci. Soc. Libya.

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LAURO MORTENLecturer of Applied Petrography, Univ. of Bologna, Italy; Address: Istituto diMineralogia e Petrografia, Universita di Bologna, Piazza di Porta S Donato 1, 40127Bologna, Italy; Employment History: University of Bologna, Institute of Mineralogyand Petrography, Post Doctoral post 1969-1971, Assistant Professor 1971-1973,Lecturer of Petrography 1974-1975, Lecturer of Applied Petrography 1975 to present;1973-1974 Lecturer of Mineralogy, Univ. of Camerino; 1976 and 1977 Short visits asinvestigator to Mineralogik-Geologik Museum, Oslo; Academic History: Doctoraldegree in Geological Sciences, Univ. of Bologna; Society Affiliations: Italian Geol.Soc; Ital. Min. and Pet. Soc, Norwegian Geol. Soc.

SEDDIK L. NAASHead of Civil Eng. Dept., Faculty of Eng., Univ. Al Fateh, Tripoli; Address: Faculty ofEngineering, Univ. Al Fateh, P.O. Box 1098, Tripoli, SPLAJ; Employment History:Assistant Lecturer, and Lecturer Univ. Al Fateh; Academic History: B.Sc. (Eng.),M.S., Ph.D.

STANISLAW OSTAFICZUKSenior Lecturer, Inst. Geol., Warsaw Univ. Poland; Address: Bruna 34m, 40, 02-594Warszawa, Poland; Employment History: 1960 to present, Faculty of Geology, Univ.Warszawa, assistant lecturer through to senior lecturer; consultant to Polish MiningAss.; Academic History: Warsaw Univ., M.Sc. 1960; Ph.D. 1967, training in remotesensing, USGS. 1977.

HANS-JOACHIM P. PACHURProfessor, Physical Geography, Free Univ. of Berlin; Address: Geomophological Lab.,Altensteinstr. 19, D-1000 Berlin 33; Employment History: 1967-1968 Head of FreeUniv. of Berlin's Research Station, Tibcsti Mountains; since 1972 Professor of PhysicalGeography in Berlin, doing research on the Sahara; Academic History: Doctor ofScience, 1966.

PHILIPPE PALLASSenior Hydrogeologist, UNFAO, attached to Secretariat of Dams and WaterResources, Tripoli; Address: C/O UN. P.O. Box 358, Tripoli, SPLAJ; lEmploymentHistory: 1956-1959 Chief of geophysical team, Compagnie Generale de Geophysique,Paris; 1961-1964 Assistant-director, Compagnia Mediterranea di Prospezioni, Rome,1964 to present, Hydrogeologist for UN working in Haiti, Niger (from 1968-1970 asproject manager), Algeria and Tunisia (as project manager) and Libya (1972 topresent); Academic History: Diploma of Engineer, ENSG, Ecole Nationale Superieurede Geologie Applique et de Prospection Miniere, Nancy, France, 1956.

SUDHIR M. PANDEYGeophysicist, Secretariat of Dams and Water Resources, Tripoli; on deputation ofIndia; Address: P.O. Box 5332, Tripoli, SPLAJ; Employment History: 1969-1971Senior Research Assistant, Central Arid Zone Research Inst., Jodhpur, India; 1971 topresent, Junior Geophysicist, Groundwater Dept., Govt. of Rajasthan, Jodhpur; 1975to present on deputation to Sec. Dams and Water Res., SPLAJ; Academic History:Banaras Hindu Univ. B.Sc, M.Sc. (Geophysics).

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NICOLE PETIT-MAIREHead of Research, Quaternary Geology Laboratory, National Center for ScientificResearch. France; Address: Centre Universitaire de Luminy, 13288. Marseille, France;Employment History: 1952-1953 and 1973-1976, Senior Lecturer, National Universityof Mexico and School of Anthropology, Mexico; 1970-1976, Senior Lecturer. Facultyof Science, University of Paris VII; 1976 to present. Quaternary Geology Laboratory;Doctoral d'Btat; Member of the Council of the Society of Anthropology of Paris; PrixBroca 1967.

J. DAN POWELLChief Research Geologist, Metals Div. Union Carbide Corp., USA; Address: UnionCarbide Corp., Grand Junction, Colorado, USA; Employment History: 1961-1963Research Geologist, CONOCO; 1963-1970 Assistant/Associate Prof. Univ. Texas,Arlington; 1970-1974 Prof. Geol. Univ. Idaho, Moscow, Idaho; 1974-1976 Geologist,U.S. Geol. Surv., Denver; since 1976 in present position; Academic History: Univ.Texas, Austin, Ph.D. 1961; Society Affiliations: AAPG, SEPM, Paleontological Soc.

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T.S. RAJUHydrologist, Secretariat of Dams and Water Resources, Benghazi Branch, SPLAJ;Address: P.O. Box 1301, Benghazi, SPLAJ; Employment History: 1960-1975 CentralGroundwater Board of India, Hydrogeologist, then from 1966 Senior Hydrologist;since 1975 with Sec. Dams and Water Resources, SPLAJ; Academic History: AndhraUniv., India. M.Sc. 1960; Delft, Netherlands, Diploma in Hydrological Engineering1970.

EVA R. REYMENTLaboratory Assistant, Palaeontological Museum, Univ. Uppsala, Sweden; Address:P.O. Box S88, S-751 22 Uppsala, Sweden; Joint author with her husband, R.A.Reyment, in a number of papers on micropalaeontology.

RICHARD A. REYMENTProfessor of Geology and Head of the Dept. of Historical Geology and Palaeontology,and Director, Palaeontological Museum, Univ. of Uppsala; Address: UppsalaUniversitet, Box 588, S-751-22 Uppsala, Sweden; Employment History: 1950-1956Geologist, Geol. Surv. Nigeria; 1956-1963 Docent In Historical Geology andPalaeontology, Univ. of Stockolm; 1963-1965 Professor of Petroleum Geology andHead of Geol. Dcpt.. Univ. of Ibadan, Nigeria; 1965-1967 Associate Professor ofBiometry, Univ. of Stockolm; 1967 to present Univ. of Uppsala; Academic History:Univ. of Melbourne, B.Sc, 1948, M.Sc, 1955, D.Sc, 1967; Univ. of Stockholm,Filosifie Licentiat, 1955, Filosofie Doktor, 1956; Society Affiliations: Royal StatisticalSociety (fellow) Geol. Soc. Sweden (Past President and Member of ExecutiveCommittee); Swedish National Commitee for Geol., Int. Palaeontological Ass.(Member of Council), Int. Ass. for Mathematical Geol. (past President, and founder).

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SAMIR RIADAssistant Professor of Geophysics, Assuit Univ., Egypt; Present address; 18, AdnanEl-Madani St., flat 6, Journalists City, Dokky, Cairo, Egypt; Employment History:1961 Researcher, Atomic Centre, Egypt; 1963-1969 Fellowship to USSR; 1970-1971Geophysicist, Egyptian Geol. Sun.; 1971-1975 Lecturer, Dept. Geol. and since 1976Assistant Professor at Assuit Univ.; in 1975 consultant to Gulf of Suez Petr. Co.;Academic History: Cairo Univ., B.Sc. 1961; Moscow State Univ., Ph.D. (Geophysics)1969; Society Affiliations: European Ass. Expl. Geophysicists, Geol. Soc. Egypt,European Geophys. Soc.

JOHN J.W. ROGERSW.R. Kenan Jr. Professor of Geology at Univ. of North Carolina; Address: ChapelHill, North Carolina 27514, USA; Emplyment History: Rice Univ., Houston, Texas,1954-1974, Instructor, Asst. Prof. Assoc. Prof., Professor (after 1963), then ChairmanGeol. Dept. (after 1971); Univ. of North Carolina in present position 1975 to present;Academic History: California Inst. Technology, B.S. 1952; Univ. of Minnesota, M.S.1952; California Inst. Technology, Ph.D. 1955; Society Affiliations: GSA, Min. Soc.Am., Gcochem., SEPM, AAPG, Am. Geophys. Union.

PIERRE ROGNONProfessor and Director Dept. Physical Geography, Univ. Pierre et Marie Curie, France;Address: 4 Place Jussieu 75230, Paris Cedex 05, France; Employment History:1957-1962 Assistant, Univ. Algiers, and associate member Inst. RecherchesSahariennes; 1962-1964 Geomorphological research, Centre National de la RechercheScientifique, Paris; 1964-1968 Associate Prof. Univ. Nancy; 1968-1970 IngeniorGeologist, Inst. Francais du Petrole, Saharan research; 1970-1975 Prof. PhysicalGeogr., Sorbonne, Paris; since 1973 in present position; Academic History: 1968Thesis of Physical Geogr. (on Hoggar, Sahara); 1972 Thesis of Geology, coauthor of«Les gres du Paleozoique inferieur du Sahara* (Technip. Publ.). Manager of ERA 684Geomorphology and Paleoclimatic evolution in arid zones (CNRS, Paris).

PAVEL ROHL1CHResearch Geologist. Geoindustria, Czechoslovakia; Address: National Enterprise, UPruhonu 32. 170 00 Praha 7 (Prague), Czechoslovakia; Employment History:1954-1958 Assistant Professor, Charles University, Prague, 1958-1962 Geologist,National Enterprise, Czechoslovakia Roads; since 1963 with Geoindustria; AcademicHistory: Charles University, Prague, B.Sc. 1954; Ph.D. 1961; Dr. Rer. Nat. (RNDr)1966; Society Affiliations: Czechoslovak Soc. Min. and Geol.

EDWARD P.F. ROSELecturer in Geology af Bedford College, Univ. London; Address: Univ. London.Regents Park, London, NWI 4NS; Employment History: Bedford College, 1966-68Assistant Lecturer, 1968 present, Lecturer; Academic History: Oxford Univ.1960-1966, graduated 1963, Ph.D. in 1966; Society Affiliations: Palaeontological Ass.(Vice President), Paleontographical Soc. (Council Member), Geol. Soc. London, Inst.Water Engineers and Scientists. Also U.K. National Correspondant for twoUNOSCO/IUGS projects. IUGS «Working Party on the Palaeogene - NeogeneBoundary*.

PIERMARIA L. ROSSIAssistant Professor of Mineralogy, Univ. Bologna, Italy; Address: Istituto diMineralogia e Petrografia, Piazza di Porta S. Donato 1, 40127 Bologna Italy;Employment History: 1971, appointed Assistant Professor, Univ. Bologna; 1972-1973Lecturer, Univ. Camerino; since 1973 at Univ. Bologna; Academic History: Univ.Bologna, Ph.D.; Society Affiliations: Italian Geol. Soc; Italian Min. and Pet. Soc.

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KAMEL E. SADEKOwner Director of Consulting Office for Drillinggapand Ground Water Investigations,Tripoli; Address: 3 Sumatra St., P.O. Box 2773, Tripoli, SPLAJ; Employment History:1964-1967 Geologist, Um Al Jawabi Oil Co., Tripoli; 1967-1974 Govt. LandReclamation and Development Projects; since 1974 in present position; AcademicHistory: Faculty of Science, Tripoli, B.Sc. 1964; courses in Geophysics and PetroleumGeology at Maryland Univ., USA; Society Affiliations: Earth Sci. Soc. Libya.

JOSEPH SALAJGeological Consultant, Strojexport-Geoindustria Czechoslovakia, geolgical mappingand editor of a Hammada El Hamra regional map, for Industrial Research Centre,'SPLAJ; Address: Institut of Geology, Mlynska Dolina 1, Bratislava, Czechoslovakia;and Strojexport-Drilling Section, P.O. Box 2962, Tripoli, SPLAJ; EmploymentHistory: 1956-1966 Research Scientist, Institute of Geology, Bratislava; 1967-1975Geologist, Service Geologiquc de Tunisie; in 1974 Gen. Sec. 6th AfricanMicropalcontological Coloquium in Tunis; 1977 to present, Geological Mapping inSPLAJ; Academic History: Charles Univ., Prague, B.Sc. 1956; R.N. Dr. and C.Sc.1963; Universite Pierre ct Marie Curie, Paris, Doctor d'Etat es Sciences, 1976; SocietyAffiliations: Czech. Ass. Geologists and Mineralogists, Geol. Ass. Nat. Hist. (Vienna).

MOSTAFA J. SALEMLecturer, Geol. Dept., Univ. Al Fateh, SPLAJ; Address: P.O. Box 13258, Tripoli,SPLAJ; Emplyment History: Univ. Al Fateh, 1968-1969 teaching assistant, 1971-1972teacher, 1977 to present Lecturer; Academic History: Univ. Al Fateh, B.Sc. 1968;Graduate School, Univ. Missouri-Rolla, M.Sc. 1971, Ph.D. 1977.

ALI M. SBETAAssistant Professor, Geology Dept., Faculty of Science, Univ. Al Fateh, Tripoli;Address: Geol. Dept., Univ. Al Fateh, P.O. Box 13258, Tripoli, SPLAJ; AcademicHistory: Oxford Univ., U.K., Ph.D.

KARLHEINZ SCHAFERProfessor of Geology at the Geologisches Institut der Universitat Karlsruhe; Address:Geologisches Institut der Universitat, 75 Karlsruhe, Fed. Rep. Germany; EmploymentHistory: 1961-1966 Research and teaching positions Univ. of Clermond Ferrand,France, and Univ. of Mainz, Germany; 1966 to present, Assistant Professor, AssociateProfessor then Apl. Professor Univ. of Karlsruhe, Germany; (1971-1972, VisitingProfessor, S.W. Missouri State Univ., USA); Academic History: Univ. of Frankfurt,B.S. 1958; Univ. of Mainz, M.S. 1962, R.N.Dr. 1965; Univ. of Karlsruhe, Dr habil.1971; Society Affiliations: Deutsche Geologische Gesellschaft, GeologischeVereinigung, American Geophys. Union, Pollichia.

ERHARD SCHULZResearch Assistant, Geographisches Institut der Universitat Wurzburg, Fed. Rep.Germany; Address: 8700 Wurzburg, Am Hubland, Fed. Rep. Germany; AcademicHistory: Studies at the Free Univ. of Berlin and the Univ. of Copenhagen; fielwork inGreece and Central Sahara, on Pleistocene and Holocene vegetation and climate.

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9ABDU A. SHATADirector, Desert Institute, Cairo, Egypt; Address: Desert Onst. El Mataria, Cairo,Egypt; Employment History: 1944-1951 field geologist for Esso, Egypt; 1951-1971research geologist, Desert Inst., Cairo; 1971-1974 Petroleum Exploration Supervisor,National Oil Corp. Libya; 1974-1975 Coordinator, Joint Venture Petroleum Expl. andProd., NOC; 1975 to present, Director, Desert Onst. Cairo; Academic History: CairoUniv., B.Sc. 1944, MSc. 1953, Ph.D. 1955.

NASREDDIN SHERIFLecturer, Univ. Al Hatch, Tripoli, at present on leave as Ph.D. research student atImperial College, Univ. London; Address: Geol. Dept. Imperial College, Royal Schoolof Mines, Prince Consort Rd., London, SW7 28P; Employment History: 1964-1968geologist with Mobil Oil, Tripoli; 1966-1968 demonstrator in Geology, Faculty ofEngineering, Univ. Al Fateh; 1971-1972 Lecturer in Geology, Univ. Al Fateh;Academic History: Univ. Al Fateh, B.Sc. 1964; Univ. Toledo, Ohio, USA, MSc. 1971;thesis for Ph.D.shortly to be submitted.

JIRI SINDELARChief of Research Programma, Geoindustria, Prague, Czechoslovakia; Address:Strojexport-Geoindustria, P.O. Box 2962, Tripoli, SPLAJ; and 147 00 Praha 4, NaMlcjnku 22, Czechoslovakia; Employment History: 1950-1955 Assistant Prof.Petrology Dept., Charles Univ; 1956-1957 Chief Pctrologist, Dept. Research andUtilization of Fuels, Prague; 1957-1958 Chief Petrologist, Coal Deposits Survey,Prague; since 1958 Geol. Surv. Geoindustria, Prague, including mapping geologist,Nrway, 1968; exploration geologist Quebec Mining Expl. Co., 1969; mapping inSPLAJ 1972, 1973, 1976 and 1977; Academic History: Charles Univ., Prague, R.N.Dr., Geology and Petrology, 1952, C.Sc. 1958; Secretary for 15 years CzechoslovakClay Minerals Group.

G.D.S. SINGHSenior Hydrogeologist, Secretariat Dams and Water Resources, on deputation of India;Address: Sec. Dams and Water Resources, P.O. Box 5332, Tripoli, SPLAJ; andCentral Groundwater Board, Min. Agric. and Irrigation, Nw Delhi, India; EmploymentHistory: 1960 to present, Govt. India Service with deputations to USA, 1970-1971,and SPLAJ, since 1975; Academic History: Patna Univ., India, B.Sc. 1956, M.Sc.1958; Certificate course on groundwater development, Univ. Minnesota, USA, 1970;Society Affiliations: Ass. Indian Hydrogeologists, AAPG, National Water Well Ass.USA.

DEB SHANKAR SINHAGeophysicist, Dept. Geol. Research and Mining, Industrial Research Centre, Tripoli;Address: Ind. Res. Centre, P.O. Box3633, Tripoli, SPLAJ; Employment History:1961-1963 geophysicist, Oil and Natural Gas Commission of India; 1963-1975Assistant Geophysicist through to Senior Geophysicist, Geol. Surv. India; 1975 topresent, Ind. Re. Centre, engaged on ground and airborne geophysical exploration;Academic History: Indian School of Mines, M.Sc. (Applied Geophysics) 1961; SocietyAffiliations: Soc. Expl. Geophysicists.

SISIR C. SINHAGeophysicist, Secretariat Dams and Water Resources, Tripoli; Address: P.O. Box14495, Tripoli, SPLAJ; Employment History: 1946 to present, geophysicist Geol.Surv. India, on deputation to SPLAJ at present; Academic History: B.Sc. (Hons);Society Affiliations: M.M.G.I., Ass. of Geoscientists, India.

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WERNER SMYKATZ-KLOSSProfessor Mineralogy, Petrology and Applied Geochemistry, Univ. Al Fateh, Tripoli,SPLAJ, and Professor Mineralogy and Sedimentology, Univ. Karlsruhe, Fed. Rep.Germany; Address: P.O. Box 3932, Tripoli, SPLAJ; Employment History: 1966-1969Assistant at the Inst. Sed. Petrography, Univ. Goettingen; 1969 to present,Mineralogical Inst. Univ. Karlsruhe, Assistant, Lecturer 1972-1976, Professor since1976; Academic History: Univ. of Goettingen, Ph.D. Mineralogy, Geology andInorganic Chemistry, Dr. rer. nat., 1966; Univ. Karlsruhe, Dr. habil 1972; SocietyAffiliations: German and American Mineralogical Societies, German and Int. ClayMineral Societies, Int. Confed. on Thermal Analysis. UNESCO working Group on«Genisis of Kaolin».

ZDENEK V. SPINARProfessor of Zoopaleontology, Charles Univ., Prague, Czechoslovakia; Address: Gcol.Dept., Charles Univ., Albertov 6, 128 43 Praha 2, Czechoslovakia; EmploymentHistory: 194"5 to present, Charles Univ., Prague, Assistant, Associate Prof, after 1951,and Professor since 1965; Academic History: Charles Univ., Prague, B.Sc. 1939, DrSc; author of five books incl. «Outline of Invertebrate Paleontology».

FAYEZ M. SWAILEMHead of Environmental Physics and Hydrology Dept., Middle Eastern RegionalRadioisotope Center for the Arab Countries; Address: MERRCAC, Dokki, Cairo,Egypt; Employment History: 1963 to present, MERRCAC, demonstrator to 1968,Assistant Lecturer to 1973, Lecturer and Head of Dept. to 1978, Assistant Professor,1978; Academic History: Cairo Univ., B.Sc. 1963, M.Sc. 1970, Ph.D. (NuclearPhysics) 1972; Society Affiliations: Physical Soc. Egypt, Egyptian Soc. Nuclear Sci. andApplication, National Committee of the Int. Hydrological Decade.

HLINZ J. TOBSCHALLAssociate Professor, University of Mainz, Fed. Rep. Germany; Address: Univ. ofMainz, Geoscienccs Dept., Saarstr. 21, D6500 Mainz, Fed. Rep. Germany;Employment History: since 1968, Inst. of Mineralogy and Petrology, Univ. of Mainz,scientific assistant until 1972, Assistant Professor until 1975 and Associate Professorsince; Academic History: Univ. of Goettingen, Diplom. Degree 1966, doctoral thesis1968; Society Affiliations: Geochem. Soc, Am. Chem. Soc, Int. Ass. on WaterPolution Research, Spectroscopy Soc. Canada, Deutsche Min. Gesellschaft, Gcol.Verein.

TAREK M. TURKGeologist, Evaluation and Development Section, Industrial Research Centre, Tripoli;Address: Ind. Res. Centre, P.O. Box 3633, Tripoli, SPLAJ; Employment History:Jordan Phosphate Mines, Syrian Phosphate Mines, Ind. Res. Centre since 1972;Academic History: Damas Univ., Syria, B.Sc. 1965; Society Affiliations: Earth Sci.Soc. Libya.

BRIAN R. TURNERResearch Scientist, University South Carolina, USA; Address: P.O. Box 11487,Columbia, South Carolina, 29211, USA; Employment History: 1964-1976, Geologistwith several African Geological Surveys and consultant to mining companies and oilcompanies; concerned largely with basin analysis for coal and uranium exploration;1976-1977 Univ. of Oxford, post doctoral student; 1977-1978 Kufra Basin ProjectCoordinator, Marengo Ltd., University South Carolina; Academic History: Univ. ofHull, B.Sc. 1964; Univ. of Witwatersrand, M.Sc and Ph.D.; Society Affiliations: Geol.Soc. London, Yorks; Geol. Soc, SEPM, Int. Ass. Sedimentologists.

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JAMES R. UNDERWOODProfessor and Head of Dept. Kansas State University, USA; Address: Geology Dept.,Kansas State Univ. Manhattan, Kansas 66506, USA; Employment History:1949-1956, Sohio Petroleum Company, various Pteroleum Engineering posts, with twoyears military leave, 1951-19i3, and two years education leave, 1954-1956;1956-1965, Univ. of Texas, Austin, Instructor, Research Assistant, Lecturer and from1962 Associate Professor of Geol., with three years assigned to Univ. of Florida;1967-1977, West Texas State Univ., Associate Prof, and from 1974 Prof, of Geol. withtwo years at the Univ. of Libya as an Esso Sponsored Prof, of Geol., 1969-1971; 1977to present at Kansas State Univ.; Academic History: Univ. of Texas, B.Sc. 1949, M.A.1956, Ph.D. 1962; Society Affiliations: GSA (fellow), AAPG, Am. Geophysis. Union,SEPM, Am. Advancement of Sci., Am. Inst. Mining, Academy of Science of Texas,and of Kansas, Geol. Socs. of West Texas, New Mwxico, and Kansas, Panhandle Geol.Soc, Nat. Ass. Geol. Teachers, Ass. Geoscientists for Int. Development, Sigma Xi.

J. VAN HINTEResearch Geologist, Esso Production Research-European, France; Address: 213,Cours Victor Hugo, 33321, Bcgles, France.

ANDREW W.R. WIGHTChief Geologist, St. Joe Petroleum (UK) Corp. (Formerly Transworld Petroleum (UK)(Ltd.), London, England; Address: The Old Post Office, Church Lane, Chearsley,Bucks, England; Employment History: 1967-1968 Dept. Mineral Resources, Regina,Saskatchewan, Canada; 1972-1973 SAMEGA, 17 bis Rue Rosenwald, Paris, France;1973-1975 British Gas Corp., London; 1975 to present, St. Joe Petr. Corp.; AcademicHistory: Bristol Univ.. England, B.Sc. 1967, Ph.D. 1971; Society Affiliations:Geologists Association London; Petroleum Expl. Soc. G.B., AAPG (active member),Royal Geographical Soc. (fellow), Geol. Soc. London (fellow).

STEPHEN K. WIMANResearch Geologist, Cities Service Company; Address: Exploration and ProductionResearch Laboratory, P.O. Box 50408, Tulsa, Oklahoma 74150, USA; EmploymentHistory: 1971-1975 Research Assistant, University of Colorado Museum; 1975-1976Exploration Geologist, Impel Energy Corp., Denver, Colorado; Academic History:Miami Univ., Oxford, Ohio, 1967; Univ. of Colorado, M.S. 1973, Ph. D., 1976;Society Affiliations: AAPG, Rocky Mnt. Assoc. Geologist, SEPM.

LUDWIG J. M. WIRTHAssistant, Institut fur Geologic and Mineralogie, Univ. Erlangen-Nurnberg, Fed. Rep.Germany; Address: Institut fur Geol. and Min., Schlossgarten 5, D-8520 Erlangen,Fed. Rep. Germany; Academic History: Currently completing thesis for«Diplom-Mineraloge» degree, Erlangen; Society Affiliations: German MineralogicalSoc, Vercin. der Freunde der Mineralogie und Geologie.

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FRANTISEK WOLLERSenior Geologist with Geoindustria, Czechoslovakia, on contract to Industrial ResearchCentre, Tripoli, and Editor map sheet in Al Oufrah area; Address: Mlade gardy 5.Praha 7, Czechoslovakia, and Ind.'Research Centre, P.O. Box 2962, Tripoli, SPLAJ;Employment History: Geologist with Geoindustria, 1972 to present, working as juniorthen senior geologist mapping in Libya 1972-1974 and 1976-1978; Academic History:Charles Univ., Prague, Graduated 196S, Doctor of Natural Sciences 1976.

MAREK ZALUSKIDrilling and Water Investigations Consultant, Tripoli, SPLAJ; Address: P.O. Box2773, Tripoli, SPLAJ; Employment History: 1963-197i positions in Poland with RuralWater Supply Enterprise, Institute of Geology, Academy of Sciences and ResearchInst. on Environmental De.; 1976 to present with Consulting Office for Drilling andWater Investigations, Tripoli; Academic History: Univ. of Warsaw, M.Sc.(Hydrogcology and Engineering Geology) 1963, Doctor in Natural Sciences 1971;Society Affiliations: Polish Geol. Soc, Int. Ass. Hydrogeologists, National Water WellAss.

BORIVOJ ZARUBAChief Macropaleontologist, Dept. Macropaleontology, National Museum, Prague;Address: Prague 1, Wenceslas square 68, Czechoslovakia; Employment History: since1965 in present position; Academic History: Charles Univ., Prague, graduated 1961,Candidate of Science 196").

HLJSNI ZEINO - MAIIMALATChief Hydrogeologist, Wakuti Company, Fed. Rep. Germany; Address: Wakuti Co.,Loehrstr. 15, 5900 Siegen 1, Fed. Rep. Germany; Employment History: 1968 and1970-1974. Hydrogeologist, Fed. Geol. Surv. and Water Board of Hanover; since 1974with Wakuti Company; Academic History: Technical Univ. of Hanover, B.Sc. 1968,Doctor of Science 1972; Society Affiliations: Int. Ass. of Hydrogeologists.

AHMED S. ZENTANIChief Geophysicist, National Oil Corp., Tripoli; Address: P.O. Box 2655, Tripoli,SPLAJ; Employment History: 1968-1970 Teacher, Garian Secondary School, SPLAJ;1970-1971 Labs. General Admin. Roads, Tripoli; 1971 to present, at N.O.C.;Academic History: Faculty of Science. Tripoli, B.Sc. 1968; Purdue Univ., USA, M.Sc.1975.

90

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