MAGAZINE OF THE MAGAZINE OF THE GEOLOGISTS ASSOCIATION GEOLOGISTS ASSOCIATION Volume 4 No. 2 June 2005Volume 4 No. 2 June 2005GAGA
Meetings June to OctoberLost City of SuffolkOman Revisited
Visit to New ZealandFossil Fest 1 Barbados
Weekend Field GuidesRockwatch
is published by the GeologistsAssociation. Four issues are produced in the year. ISSN 1476-7600Production team: Susan Brown, Mark Campbell, Paula Carey, John Crocker, Bill French, Tony Iles, Julia Spencer
Printed by GRAYAM PRESS, Billericay.
The GEOLOGISTS ASSOCIATION does not acceptany responsibility for views and opinionsexpressed by individual authors in this magazine.
The Geologists AssociationThe Association, founded in 1858, exists to foster theprogress and diffusion of the science of geology, and toencourage research and the development of new methods.It holds meetings for the reading of papers and the deliveryof lectures, organises museum demonstrations, publishesProceedings and Guides, and conducts field meetings. Annual Subscriptions for 2005 are £38.00,Associates £28.00, Joint Members £56.00, Students£16.00.For forms of Proposal for Membership, and further informa-tion apply to the Executive Secretary, The GeologistsAssociation, Burlington House, Piccadilly, London W1J 0DU. E-mail [email protected] Telephone 020 7434 9298 Fax 020 7287 0280Website: http://www.geologist.demon.co.uk
President: Robin CocksExecutive Secretary: Sarah StaffordHonorary Vice Presidents:
Professor Allan Rogers
Magazine of theGeologistsAssociation
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GA Magazine of the Geologists Association vol. 4, No. 22
CONTENTS
3. The Association
4. GA Meetings
June to October
7. Letter from the
Presidents
of GA and GS
10. Book Reviews
12. Mark Campbell in
New Zealand
14. Pillow talk - Oman
Revisited
16. Rockwatch
18. Weekend Field Guides
19. Book Review - Deserts
20. Dunwich, the geology of
Suffolk s lost
Cover picture: The Wahiba Sands dune com-plex in Oman covers 15,000 km2 see pages 14
ADVERTISEMENTSWhile precautions are taken to ensure the validity ofadvertisements the Association is not responsible forthe items offered, for any loss arising or for their c-
NOTICE CONCERNING FIELD MEETINGS: The Association now has a mobile phone for emergency communications concerning field meetings (UK only). If you have to cancel on tday, or are lost or late for the start of a fielmeeting, please call the GA mobile phone (07990806961). The mobile phone will only be switched on justbefore and during field meetings.
THE ASSOCIATION
3
REPORT FROM COUNCIL
This is the time of year when items for theAnnual General Meeting are considered. TheTreasurer reports to Council on the health ofthe GA finances and presents the draftaccounts and next year s budget for Council sapproval so that they can be incorporated in theAnnual Report which has recentlybeen circulat-ed to members, for their approval at the AnnualGeneral Meeting. Council also discussestheproposals of the Awards Committee on whoshould be offered medals and awards for theircontribution to the Association and Geology.The nominations for next year s Council arealso reviewed.
After the annual meeting of Local Groupsand Affiliated Societies, which was held beforethe Reunion in Cardiff, it was agreed that the
Association should sponsor a meeting awayfrom London. Fortunately the North StaffsGroupexpressed willingness to host the meet-ing on November 10th and there was generalenthusiasm by Council for the event and theTreasurer agreed that the GA should give somefinancial support.
An initiative from the Geological Societysuggested that we combine the celebrating oftheir 200th anniversary in 2007 and with thatof the GA s sesquicentenary in 2008 with aseries of meetings both at Burlington Houseand throughout the UK. Council agreed thatthe initiative should be pursued.
After a considerable amount of work theRules of the Association are in a form whichcan be presented to the Charity Commission. Itwas agreed that the new Rules should be cir-culated to members for their approval at a
Special General Meeting in July.Council was asked if Affiliated S
members could attend the GA lectures they were GA members i.e. for free. Ipointed out that Affiliated members nable to do this and their entitlement extends to attendance at GA Field Tripuse of the Library and does not inclu-dance at lectures for free. It was agrecord would be kept of any payments mfor entry and they could be deducted subscription fee if an individual decthe GA that year.
Council was informed that from A2006 Burlington House will not be avalectures, due to renovations and the will have to be held elsewhere for a pup to 30 weeks. It is expected that tuse the more expensive English Herit
FROM THE LIBRARIAN
First of all I must thank one of our Membersfor the donation of an antiquarian book, thesale of which has brought in funds for theAssociation. Duplicate geological mapsdonated some time ago are now beingoffered through GA Enterprises at our month-ly meeting and again money is being raisedthrough their sale.
To return to the present, we havereceived two current publications of the BGS.The first of these is Davies, J.R. et al.2004.Geology of the country around Flint, Memoir ofthe British Geological Survey, sheet 108(England and Wales). ISBN 085 272 487X£40.00.
This covers an area roughly from Ruthin
and part of the Vale of Clwyd in the south-west to Ellesmere Port in the north-east witha lovely picture of the heather clad slopes ofMoel Fa Mmau on the front. A nostalgic viewfor me as my class climbed this hill on our firstgeography field trip aged about twelve. Thismemoir follows the standard BGS format withclear diagrams and photographs with gooduse of colour. The area was economicallyimportant covering the Denbighshire coalfieldand the north-east Wales orefield mainly forlead, silverand zinc, and even a little gold.With my other interest in garden history I wasfascinated to learn that calcareous tufa fromthe Wheeler Valley has been used in the con-struction of features at Kew Gardens.
Secondly we have Cooper, A.H. et al.2004. The Skiddaw Group of the English LakeDistrict. Memoir of the British Geological
Survey. ISBN 085272 484 5. £35.00This is a thematic memoir coverin
parts of 1:50000 sheets 22 Maryport, Cockermouth, 24 Penrith, 28 WhitehaveKeswick, 30 Appleby, 31 Brough and 48Ulverston. An introduction includes -ry of geological investigations, follchapters on biostratigraphy, lithostrdepositional environments, structure, -morphism, regional correlation, informsources and an light page bibliographAppendices list localities, analyses, include a fossil inventory.
All of this is supported by clear-graphs and diagrams. There is a pagphotos devoted to Acritarchs from theSkiddaw Group which I admit I had nevheard of until our trip to the Isle otime ago where they are extremely rar
CURRY FUND REPORT
At the March meeting of the Curry Fund Committee there were four-teen new applications, one deferred from the December meeting await-ing supplementaryinformation and one tabled request for support. Ofthe new applications, nine were funded, four refused and one neededfurther information before a decision could be made. Both the latetabled request and the deferred one were funded.
£100 was awarded to Simon Carpenter to support a Jurassic fos-sil display at Frome Museum. Marble Arch Caves European Geopark inNorthern Ireland was awarded £500 towards the cost of a Family FunDay being jointly run with Rockwatch and the National Botanic Gardenof Wales was granted£2000 towards the cost of a geological garden.The Harrow and Hillingdon Geological Society application for £168 forthe cost of putting a small geological display in a local public garden wasalso granted. The GA was granted£5900 towards the cost of reducingthe deficit accrued from the Earth Alert Festival in Scarborough in 2002and Jeff Liston was awarded £182.20 for the cost of colour plates toillustrate his article in a Geological Society publication on the History ofPalaeobotany. £1761 was awarded to the Charmouth Heritage CoastCentre for microscopes and other equipment to enhance its educationprogramme. GeoSuffolk (Suffolk RIGS) received £1440 for the publi-cation of leaflets illustrating the local geology (see right) and AvonRIGS was awarded £622 for a leaflet on the Geology of the BristolDistrict.
Applications from the University of Portsmouth, Oxfordshire
Geology Trust, the Bath Royal Literary & Scientific InUniversity of Bristol were refused, all of them fallin
of the Guidelines.
The application deferred from the December meetingGwynedd and M n RIGS was granted £1500 towards the cos-ducing a booklet on the Dyke Swarms of Anglesey, and Kreceived £100 to enable two members to attend a seminaRagstone.
The grants awarded at this meeting illustrate the range of geological initiatives that the Curry Fund is
GA magazine of the Geologists Association Vol. 4, No. 2,4
JUNE MEETINGThe explo-ration ofAntarctic sub-glacial lakes
Martin J. Siegert Bristol Glaciology Centre, School ofGeographical Sciences, University ofBristol, Bristol BS8 1SS, UK.
Friday, June 3rd 2005Geological Society, Burlington HousePiccadilly, W1V 0JUat 6.00 pm, tea at 5.30 pm
Over 140 liquid water lakes have beenidentified beneath the ice sheets ofAntarctica (Figure 1). They were discov-ered by British glaciologists in the1970s using ice penetrating radar tomap the bed surfaceunderneath theAntarctic ice sheet. In a number ofplaces, they measured the base reflec-tor to be unusually flat, smooth andbright (Figure 2). Such reflections canonly come from the ice-water interfaceof a subglacial lake. The largest andmost well known of these lakes is the250 km long Lake Vostok. The majori-ty of Antarctic subglacial lakes aremuch smaller, having lengths ofaround 10 km. All subglacial lakes arelocated beneath ice in excess of 3 kmthick, and are likely to have waterdepths of the order of 10s-100s ofmetres. Subglacial lakes are thereforesignificant bodies of water, isolatedfrom the atmosphere for, possibly, mil-lions of years.
Subglacial lakes research isunderpinned by two hypotheses. The
first is that Antarctic subglacial lakescontain microbiallife, and because thehabitat is extreme and ancient, thesemicrobes may be unique. To date, nodirect measurements have been madein any subglacial lake. Such work is,however, the only way to identify andunderstand life in these extreme envi-ronments. Instruments developed forthe exploration of subglacial lakes areanalogousto those needed to identifylife in extra terrestrial bodies forthree reasons. (1) Life in subglaciallakes is likely to be sparse, and soidentification of this life will be a sig-nificant challenge for instrumentsdeveloped. (2) The instruments mustoperateremotely and feed informationback to a distant receiver. (3) Theequipment must be miniaturised and
fitted into a 15-cm diameter cylin(to allow it to pass down an ice b-hole).
The second hypothesis is thatsediments on the floors of subglaclakes contain a record of environm-tal change. Such records may beextremely valuable in understandingthe poorly constrained histories ofboth the East and West Antarctic icesheets. As lake-floor sedimentswill besoft, and accumulation rates low, deep-time sequence could be extrac-ed using short gravity cores.Consequently, if subglacial lakes can accessed, sedimentaryrecords fromtheir floors may be relatively easacquire.
The Scientific Committee onAntarctic Research (SCAR) set up agroup of specialists in 1999 to -sider and recommend mechanisms forthe international coordination of -glacial lake exploration programmeThey noted that the large size of Vostok means that it will take decto be characterised to a meaningfudegree. A smaller subglacial lakecould, however, be measured to anaccurate level by a single dedicatfield season. A UK-led proposal exto survey a 10 km long lake in WesAntarctica, named subglacial LakeEllsworth. In a few years time, af
Figure 1. The locations of 145 Antarctic Subglacial lakes.
Figure 2. Anice-penetrat-ing radarimage of anEast Antarctic subglaciallake.
GA Magazine of the Geologists Association Vol. 4, No. 2, 2005 5
’Evolution ofthe four-legged fish:new views ofan earlytetrapodicon’
Dr Jennifer A. Clack,
Reader in Vertebrate Palaeontology
University Museum of Zoology,
Downing St.,
Cambridge CB2 3EJ, UK
Ichthyostega from the Late
Devonian of East Greenland has long
stood as an icon representing a
’transitional form’ between fish with
fins and tetrapods with limbs and
digits. For decades, it was the only
known Devonian tetrapod, and
remains one of the few for which
articulated specimens have been
discovered. However, new interpre-
tions in the light of new information
have thrown a very different light on
this animal, showing it to be highly
specialized, even bizarre, in many
respects. This talk traces the evolu-
tion of ideas about Ichthyostega in
JULY MEETING
Below, a partially articula
specimen showing head,
trunk and forelimb of
Above, a hind limb in which
part and counterpart speci-
mens have been superim-
posed photographically.
DUNWICH -
Suffolk s lost cityArticle byRoger Dixon(See page 20)
Left: Part of the Medieval wall rthe Greyfriars monastry site atDunwich including an arched entra
GA Magazine of the Geologists Association Vol. 4, No 2, 6
OCTOBER MEETINGThe Silverpit Crater:resolving a geologi-cal controversy.
Kevin Smith, British Geological Survey, Edinburgh
The Silverpit Crater, which has been described as theUnited Kingdom s first impact structure, lies buriedbeneath 300-1500m of sediments approximately 140 kmto the east of Scarborough in the southern North Sea.Best defined at top Upper Cretaceous level, this unusualearly Cenozoic ring structure consists largely of closelyspaced concentric normal faults, up to 20 km in diameter. Acone-shaped uplift at Jurassic level beneath the centre ofthe structure possibly formed by collapse of the craterwalls following the initial explosion. Detailed studies of 3D seis-mic reflection data across the crater, computer simulationsand preliminary reports of the discovery of impact-relatedmaterial have provided subsequent support for an impactinterpretation. Additional evidence may be obtained fromrecent hydrocarbon exploration wells in the area. TheSilverpit Crater has already been added to global databas-es of impact features and is widely seen as a potentialstructural template for less well preserved impacts else-where.
Some puzzling aspects of the relationship betweenthe Silverpit Crater and the geology of the southern NorthSea have prompted other geologists to question whether itwas formed by a random extra-terrestrial event. Firstly,regional structural maps and seismic sections show thatthe crater lies in the centre of a syncline formed by thedisplacement of a thick underlying layer ofPermian salt, raising the possibility that thecrater is associatedin some way with salttectonics. Secondly, if the crater faults arerelated to impact, then the collision musthave occurred fortuitously during a Cenozoic tectonicepisode in which similar nearby faults werealready being formed. Thirdly, seismic inter-pretation has revealed that the location ofthe crater appears to coincide with pre-exist-ing structural and stratigraphical features inthe pre-Permian basement.
In this talk, all the various proposals forthe origin of the Silverpit Crater will be
reviewed, with the aid of seismic reflection data
analogues and geological observations from a wide
Above: The author at the Musselburgh ash lagoons wiEdinburgh and Arthur s Seat in the background. Photo
L. V. Smith.
Right: A pattern of concentric ring faults devel-oped in waste from a coal-fired power station(boot for scale): Musselburgh ash lagoons, EastLothian. Assuming that this structure was notformed by the impact of the old boot, can it pro-vide a clue about how the Silverpit Crater mighthave originated? Photo credit: L. V. Smith.
7GA Magazine of the Geologists Association Vol. 4, No 2, 2005
In 2007 the Geological Society will be two hundred yearsold and in the following year the Geologists Associationwill be one hundred and fifty. It is thus opportune to reviewand hopefully consolidate the common ground between thetwo organisations, and we feel that the two of us as thecurrent Presidents can speak with a united voice.
One thing that we are both certain about is that thetwo organisations are not competitors but natural allies.Both have geology in its widest sense at the centre of alltheir aims and activities. Both publish original scientificpapers on all aspects of Earth Sciences and encourage morework in field and laboratory, and spread the word as far andwide as possible through a variety of activities. However,the two act in different but complementary ways to spreadgeological awareness and to raise the profile of the subject.
The Association is a friendly and symbiotic mix ofboth professionalsand amateurs within its membership. Aswell as generating publications (the Proceedings, Magazineand Circular), it organises field excursions both in Britainand abroad, and has a network of Local and AffiliatedGroups which also hold lecture meetings and field excur-sions. A particularly successful and popular GA activity isRockwatch, which also has a magazine and holds meetingsup and down the country to raise enthusiasm for geologyamongst children. The Association is already closely linkedwith the Society in that the GA s office is within the Society s
apartments and the GA monthly lectures are also hBurlington House.
In contrast, the Society is at the heart of t-logical profession, with appropriate validation ocourses and professional certifications, and acts avoice to governmentand other official bodies, as wellmedia. In conjunction with the British Geologicalinitiates and acts for Britain in global geologicand standing committees. Through its Publishing HBath, the Society is the foremost geological publBritain, publishing not only its own journals andalso for various other learned societies, includithe Proceedings of the Association. The specialisthe Society are at the heart of organising meetinvaried subdisciplines, and many of those, such asPetroleum Group and the Engineering Group, contrimuch to our national wealth.
It would be very good is more people were to like ourselves, members of both organisations, pathose with formal geological qualifications we you that there is much to be gained by doing so. Society and the Association are in the early stag-ning country-wide joint events to celebrate geoloand 2008 which should not only be fun but also he
spread geological awareness within the wider comm
Robin Cocks and Peter Styles
The Association and theSocietya note from the two Presidents
A colour-filled isochron map of the top Upper Cretaceous sur-face in part of the southern North Sea, showing the SilverpitCrater and other Cenozoic tectonic features.
OCTOBER MEETING (Continued)
ASCENT OF A SMALL ISLANDThink of the Lesser Antilles and you think of a classic island arc, formedby volcanism at the edge of the Caribbean Plate. With Montserrat stillfresh in the memory and the eruption of Mont PelØe on Martinique in1902 the stuff of geological legends (Zebrowski, 2002), this is hardlysurprising. With one notable exception, all of the principal islands of theLesser Antilles had a volcanic origin. However, in this case, the excep-tion proves a different rule.
You can see that there is something a little odd about Barbadosjust by opening the correct page of an atlas. From Grenada in the southto Dominica in the middle there is one arc; north of this point there isan old (Palaeogene) arc to the east which diverges from the Neogenearc to the west (for discussion of why, see Wadge, 1994). Barbados lieson none of these, lying about 150 km east of St. Vincent. It is not partof the volcanic arc at all, but, rather, is a subaerial exposure of the topof the accretionary prism. As such, it represents a geological rarityindeed.
Yet, arriving on a flight into Barbados, the impression is one oflimestone and more limestone. Ninety percent of the surface rock expo-sure is representedby three terraces of Pleistocene reef limestones,called the Upper (oldest, but topographically highest), Middle andLower (youngest) Coral Rock. The differentelevations of these ter-races have been the result of the interaction of oscillating sea levels dur-ing the Pleistocene at the same time as the accretionary prism wasuplifted. Only where the coral rock has been eroded away, in the so-called Scotland District to the north-east, are the underlying rocksof the accretionary prism sequence exposed.
Not surprisingly, it is in the Scotland District of Barbados thatthe greatestgeological diversity occurs, consisting of a basal complexpunched through with mud diapirs and overlain by nappes. This sedi-mentary succession is comprised of diverse siliciclastics. To give an
example of just how diverse, Speed (2002, p. 58) listrock and clast types from the diapiric melange of the Formation: very coarse- and fine-grained sandstone, mu-men matrix; green mudstone granules up to a few tens -eter; lithic blocks up to 25 m in diameter, including quartz sandstone with a calcite or bitumen cement, anfossils indicative of an ancient cold seep community. Oiindicate the economic importance of this succession; produthe Woodbourne Oilfield in the southeast of the islancomplex beneath the Pleistocene limestones.
However, the Pleistocene coral rock succession is-stone . It includes shallow water limestones, with abu-ractinians, but there are also deeper water fore-reef -pected fossils such as brachiopods. The coral rock alkarst features such as caves and collapse structures. -cal clifflines on the north and southeast coasts have -phology controlled by joint systems within the limest
Speed, R. C. 2002. Field guide to the sub-Quaternary of BarGuides,16th Caribbean Geological Conference, Barba16th-21st , 1-83.
Wadge, G. 1994. The Lesser Antilles. In (Donovan, S.Keds) Caribbean Geology: An Introduction. UniversityIndies Publishers Association, Kingston, 167-177.
Zebrowski, E., Jr. 2002. The Last Days of St. Pierre: The VoDisaster that claimed Thirty Thousand Lives.Rutgers Universit
Figure 3: Limestone mushroom at Bathsheba, northwest on the Atlantic coast. Although within the Scotland Dboulders of the overlying Pleistocene coral rock from-tion, exposed in a cliff section, have rolled down tothey have been undercut by the grazing action of mari-brates feeding on algae. The small tidal range has li
Below: Simplified geological map of Barbados (redrawn andmodified after Speed et al., 1991, Journal of PetroleumGeology, 14, fig. 2). Key to tectono- and lithostratigraphic units:open stipple = basal complex; vertical ruling = diapiricmelange; O = Oceanic nappes; UCR = Upper Coral Rock; MCR= Middle Coral Rock; LCR = Lower Coral Rock. The First HighCliff (1HC) separates the LCR and MCR; the Second High Cliff(2HC) separates the MCR and UCR. Key to place names: B =Bridgetown; BA = Bath; C = Cluffs; SB = Skeete’s Bay; SD =Scotland District. Although not illustrated herein, the line of sec-tion X-Y is through the Woodbourne Trough oil field, in which
GA Magazine of the Geologists Association Vol. 4, No. 2, 2005 9
Above: Something of the structural complexity of the Tertiary succession of the Scotland Distriphotograph. This contorted sedimentary sequence is part of the Palaeogene basal complex of the
Below: Donkeys in the sugar cane fields. Four ’nodding donkeys’ extracting oil from the Woodbosoutheast Barbados.
FIELD MEETING - BARBADOSThe Geologists’ Association is arranging a field excursion to this beautiful Caribbean island tSteve Donovan in early May 2006. Please see the June Circular for details, and contact Sarah St
at the GA office for full particulars and booking forms.
GA Magazine of the Geologists Association Vol. 4, No. 2, 10
BOOK REVIEWSBASIN ANALYSISPrinciples and ApplicationsPhilip A. Allen and John R.AllenSecond editionBlackwell Publishing £37.50 PaperbackISBN 0-632-05207-4
Study Phil and John s magnificent book ifyou want to know all about plate tectonicsand the processes which lead to the for-mation and sedimentaryfill of basins.They tell you also how sediments evolveafter burial and how hydrocarbons areformed and trapped.
Processes within the mantle and lith-osphere drive plate motion; the conse-quent tectonics control basin formation,and the catchment topography which isweathered and eroded to provide sedimentfor basin infill. An explanation of this con-stantly dynamic inter-relationship is thevery heart of the book.
The physical state of the lithospheredetermines how basins are initiated andevolve. Lithospheric stretching providessag and rift basins; sag due to flexuringresults in ocean trenches on subductingoceanic plates and foreland basins onloaded continental plates; faultedstrike-slipbasins result where plates have a sub-par-allel motion. There is a detailed examina-tion of the variations of basin morphologyand evolution around these themes.
The processes of sediment supplyand fill are equally dynamic. On the conti-
nents, warmer, wetter regions allow deepand rapid weathering; in colder, dryerregions weathering is slow and shallow.These processes control the volume of sed-iment supply. Topography and transportmechanisms - wind, water, ice - controlrates of erosion and sediment supply.Topography controls the direction of sup-ply. These processes are dynamic, climatechange and erosion constantly modifyweathering and transport to an evolvingbasin.
Stratigraphic geometries reflect thedynamic relationship between tectonic subsi-dence, which generates space, and theinflux of sediment to fill that space. Thedetailed interplay between subsidence andsediment supply causescomplex variationsin depositional environmentsthrough spaceand time.
Burial leads to temperature increase,compaction and porosity reduction.Temperature increase is due to the basalheat flow of a basin (which reflects lithos-pheric mechanisms). The temperature his-tory is modified by variations in thermalconductivity of the rocks and displacementof pore fluids due to compaction. Cookingof organic matter generates oil and gas andincreases the pore fluidsavailable for migra-tion. Fluid movement responds to andmodifies the pressure regime. Fluid move-ment depends on porosity and perme-ability,and the ability of a rock to with-stand increasing overpressure before frac-turing. Fluid migration changes sedimentchemistry which may allow cementation
and consequent porosity loss.A Petroleum Play needs oil and ga
generationfrom a source, and migrationinto porous and permeable reservoir rin a trap sealed by a regional non-posediment.
This classic multidisciplinary boaddresses every discipline in detail. shows you how to analyse specific geo-ical data so you can make reasonable pre-dictions concerningthe geology whichexists away from your controlpoints. Anunderstanding of the basin models, thdynamic processes which control platemotion and basin evolution, the weath-erosion-sedimentation-burial-diagenessystem and the hydrocarbon generation
SOIL EROSION AND CONSERVATIONR.P.C. Morgan, 2005Blackwell publishing ISBN 1405117818 Paperback £29.95
Soil science is the poor relations of the Earth and Biological sSometimes soils are given coverage within these sciences and somIt is never guaranteed.
The same is true within the area of conservation. Biologicahas had a large following for many years and geoconservation is -dence with the introduction of the term geodiversity and the publicfirst book on the subjectby Murray Gray in 2003 actually including valuconserving abiotic nature in the title. Neither guarantee to covSo soil conservation has been left behind. It is the poor relatiair protection policies and quality standards too. The developmeaggregate levy sustainability fund with its emphasis on geodiver-versity conservation has the potential to help.
Soil is starting to get increased recognition due to a deveEurope (Soils and European Soil Strategy 2004). Thus it is timelrunning to its 3rd edition has been published.
The book with an international flavour but highlighting Britoo, concentrates on how extensive soil erosion occurs and its rThe need for soil conservation is justified in the first 6 chaptall aspects of soil erosion starting first with the actual science behisubject. While to many the mathematicsand formulae may be off-puttingthis is a necessary background and is minimalist. The coverage o-tion dealing with detailed surveys at different levels is valuab-
11GA Magazine of the Geologists Association Vol. 4, No. 2, 2005
BEFORE SCOTLANDAlistair MoffatThames & Hudson, London. 352 pp. 22 colour plates. 2 Maps. Published 2005. £18.95. (hardback)ISBN 0 500 05133X
’The story of the land that becameScotland is one of dramatic geologicalevents and impressive human endeavour’.For geologists this opening sentence of thepublisher’s blurb seems to promise suchtopics as Caledonian mountain building orTertiary volcanism.To find that the geolo-gy begins towards the end of the last
Quaternary glacial stage will be a severedisappointment. In fact, no real geology atall! However, a misleading blurb is no rea-son to discard a book.
This is about the peopling of Scotlandand the emergence of a distinctive Scottishidentity. In other words, it takes its shapefrom archaeology rather than geology - butnot too overtly. The author is eager tobring the story to a wider public and hischapter headings are correspondingly fanci-ful. Who would have supposedthat TheKindred Ground would prove to be a chap-ter on the Neolithic of Scotland, or HomelyGeometry, a chapter on the Bronze Age?So, in seven chapters we pass from theUpper Palaeolithic through the Mesolithic,Neolithic, Bronze Age, Iron Age and Romanperiods to a final chapter on the Dark Ages.The opening chapter however is about thenames given to the British Isles in the past,and throughout the volume the authorshows his interest in the meaning of place-names, both for the identity of place and asa record of events in the past.
The style may be popular, but thecontent is sound. In the earlier chapters onthe prehistoric period, recent archaeologi-cal discoveries from specific sites are out-lined and their wider implications forScotland are explained. The emphasis is onhow the prehistoric people of Scotlandcoped with the environmental conditions-what they ate, what their dwellings andpossessionswere like, and what can beinferred about their social organisation andbeliefs. Analogies abound - the authorargues that the life of Mesolithic hunter-gatherers was still recognisable among thelast inhabitants of St Kilda; that Highland
crofters shared problemsfaced by Neolithicfarmers; that prehistoric sea-farers v-tured out in hide boats essentially i-guishable from modern curraghs.Digressions are numerous, usually toexamine the wider context of the Scotrecord - the domestication of dogs, tprehistory of the Dogger Bank, theNeolithic axe trade, prehistoric rock -ings, and a recurrent theme - the DNA -dence that most of us are descended fhunter-gatherers who entered the Britpeninsula at the end of the last Ice AJust occasionally, the impact of geolevents has a place - the tsunami accom-nying the submarine Storrega landslid5840 BC is mentioned and the probablydisastrous consequences of the eruption oMt Hekla in 1159 BC.
The later chapters depend more onthe written record and focus more on -tifiable historic figures. The Roman p-tion of Scotland is approached througplace-names on Ptolemy’s map of Britaand the various contemporary accounts the Roman military campaigns in Scotl- notably those of Agricola, whose mothe author is pleased to note, was pra Celt. The last chapter, in which th-ern identity of Scotland is finally ras befits the Dark Ages, a shadowy tabattles, pirates, High Kings and conschanging allegiances, all recorded moless unreliably by monkish chroniclerthe middle ages.
Although there are many asides, tbook is about the influence of the pathe lives of people in Scotland todayauthor’s interest in place-names is jstrand of a pervasive interest in con
Chapter 6 covers modelling the soil erosion system. Thisdeals with several different physically based models from WEPPand GUESS to EUROSEM and so includes European research.
The core of the subject - Strategies for erosion control iscovered in Chapter 7. Here it is gratifying to see pipeline restora-tion, mining reclamation and urban areas covered after the tradi-tional approaches to soil conservation for cultivated land andforestry. The following chapter deals with crop and vegetationmanagement while the small Chapter 9 deals with soil manage-ment concentrating on tillage.
Chapter 10 looks at mechanical methods of erosion controland has an interesting section on the use of geotextiles. Thepenultimate chapter looks at implementation of suitable protectionmeasures, as this is the ultimate objective of research on soil ero-sion. Thus the wider context is discussed from political and leg-islative aspects to financial limitations. The last short chapter looksto the future. It highlights why soil conservation projects havefailed in the past and how a logical approach to framework analy-sis must be adopted. However it does stress that like extinction inpalaeontology, soil erosion is a natural process -part of the rockcycle - but it is the accelerated rate of the process that gives causefor alarm. Implications from Climate change are also mentioned.
Many of the problems with this book are not the responsibil-ity of the author but the publisher. Thus Boxes are difficult to readas they have been reproduced on a dark background. The index israther small at less than 6 pages but the reference list is vast at34 pages. Thus if you wish to follow up a topic once you are insidethe book that is fine but if you wish to enter the book you may beunable to find your starting topic heading. Overall the typeface is
small, which does detract from the readability but allmaterial to be covered per page. Many of these matters-nomically driven.
I would like to finish with a quote from the last Soil conservationis an interdisciplinary subject. It requunderstanding of geomorphological processes, agriculturaland the organisationalstructure of the society to design sustfarming systems .Thus it is an essential requirementfuture to change public attitudes so that they will su-cept of natural rights for soil, which need to be protected. I seemto have heard this before. Let us hope that the publiclisten to all ourpleas and that this book helps them to do this.
BOOK WANTEDDinosaurs of the Flaming CliffsMichael Novacek (Published 1996)Anchor Books (Doubleday) New York
Roger Dixon wishes to obtain a copy of tbook and would appreciate any help that be given. If you can help please contacGA office.
I was fortunate enough to visit New Zealand, due to my "significantOther" being a Kiwi by birth and having had a long wish to go "downunder . Though large parts of my several week long trip were inter-rupted by visits to "in laws" etc., it was a great opportunity to explorewhat most geologists assume is a Mecca but are not sure of exactlywhy. Well let me explode a few myths: The roads are wonderful andmostly empty, most people live in the worst parts of their magical land,and Rotorua was not the most interesting part.
What other immediate points come to mind? There is almost noGeoconservation/promotion to be seen anywhere, which is disap-pointing as the potential is clearly huge. However they have a won-derful set up of "Reserves" all over both islands and a huge networkof "trails" that include some wonderful scenery and geological poten-tial. The country is far more tropical and vegetated than the impres-sion gained in Europe suggests. You don’t see sheep everywhere butthe roads are littered with dead possums which is an alien and verydamaging species in New Zealand).
So what did my trip consist of? We began in Christchurch on theeast coast - S. Island. This sits on the edge of the huge outwash plainsfrom the Southern Alps and is made up of Pliocene- Pleistocene sedi-ments. Adjacent to it sits the Banks Peninsular which is basically thestumps of two large volcanoes of mainly Miocene age. These havebeen heavily eroded and provide some lovely sections through ash, sco-ria, basalt and andesite. There is also a bizarre quarry on the westside at Halswell which shows a curved planar jointingpattern whichwas exploited for paving slabs!!. Travelling over the southern Alpsthrough Arthur’s Pass provided a superb way to view the two very dif-ferent sides of the S.Island. The route up towards Lewis pass affords
some stunning views especially of river terraces whichquite outstanding- far better than any "text book" examplis the magical moment as one passes the great divide/Awhere the Indian plate meets the Pacific plate. The weGreymouth is quite simply stunning. Why no one lives hunderstand. Some think its too wet !! Well it was verwhen we were there. The narrow coastal plain is brokenPaparoa Range of Oligocene and Eocene sediments. Theselimestones, sandstones and coal measures. This makes fscenery and lots of good sections. They also allow thestrange karstic "Punakaiki Rocks", where the sea has mholes through the limestones. The Pleistocene sands and grthat surround theses mountainsare gold bearing and show theremains of past "gold rushes". What makes this area sodegree to which the native scrub and "bush" still drapland surface no matter how steep like a huge very thicvegetation is almost tropical and very dense with cree-severywhere. Crossing back through the Alps further noLewis Pass affords another opportunity to see the junctitwo plates (Indian/Pacific)along the Alpine fault. This faul-rates the remnant of Australian Gondwana that split awCretaceous along with some arc sediments from the wholMesozoic and later ocean floor sediments (Torlesse) fopacific plate. These have been rammed up against one another byplate tectonics and docking to form the huge Southern Alps. Theseare still being uplifted at about 1-2 cms per year andhasjust managed to keep pace. We moved onto the North Islair and traversed the northern coast from East to west. Cape is wonderfuland has a fine ophiolite sequence thrustform a large mountain. The mountain ranges inland from
MARK CAMPBELL inNEW ZEALAND
Punakaiki Rocks on the west coast up fromGreymouth.
Typical forest bush with a hillside road cut-ting.
The Rakaia river with spectacular terraces and Mt Hmade fromTorlesse greywacke.
Rotorua is a predictable tourist honey pot. My advice is aimfor geysers just away from the main town. Waimangu is a goodone but we ran out of time to explore it fully. However, there aresome lovely small steaming muds pools just off some of the roadsif you go exploring and these to me were just as interesting !
Moving west there is perhaps some of the more cultivatedand less interesting scenery in NZ. However I suppose AucklandHarbour is impressive in a urbanised sort of way. North ofAuckland you move into a mix of underlying Mesozoic (Torlesse)rocks punctured by modern volcanics and overlain by modernsoft sediments. There is some wondrous coastal scenery andpockets of surprises such as the karstified limestone belt atWhangarei. What was disturbing was to see this being sold as bro-ken lumps at the roadside for the usual ornamental purposes. Theoutcrops are small and precious and I hope the Dept. ofConservation wakes up to this soon!!
The coastline north of Auckland up towards Whangarei andRussell has some wonderful east coast beaches and rocky cliffsand huge longbeach strands on the west coast. However theinland scenery is more muted in comparison with elsewhere in thecounty. There is a wonderful quarry that cuts almost to the heartof a late Quaternary scoria cone. All the classic cone layering ofash, pumice, bombs and some lava can be seen and the adjacentlava field is easily seen in road cuttings etc. The lava fields arealso responsible for some nice waterfalls that show the usualstructures seen in lava flows. One of the spin offs of high heatflow and high erosion rates has been that there are several smallEocene coalfields ( Kamo Coal Measures) and these are now atthe surface. These are associated with mudstones, greensandsand conglomerates which indicate their patchy and marginalnature. As with all initial visits to a new geological area it is diffi-cult to asses where best to go and afterwards you find all sorts ofplaces that you should have gone.
So what advice would I give to any other "first timers". Wellmaps and Geological guides are very hard to find. Most places giveyou an amused smile when you ask! It is best to contact the IGNS(Geol Survey) who are at Lower Hutt near Wellington. Even then
you can only get maps at 1:250,000 scale for the wholeand many of these are 40 yrs out of date. A new series is beinproduced but there is only about 30% coverageso far (Q mapseries). There is only one set of geological guides athese are out of print but they are available from vershops or also from the NZ Geological Society. There aror so for both islands in all so many areas have nothithe guides are good don’t expect GA standards !!!
There is one general book by J. Thornton "A field New Zealand Geology" which was a life saver but if youyour place names is a nightmare since it is a bit ligh!!! As regards where to go, well I would aim for theSouth Island where you can see all the S. Island formatogether and then travel down the west coast and lookFiordland. A few excursions could be made into the Alps to lothe main fault and the metamorphiczones in the Torlessesequence. The North Island could be done by focussinnorth coast from East Cape and then cutting down throcurrent volcanic zone at Rotorua and on to the big con
Governors Bay, Banks peninsular with the eroded rimof the Lyttelton volcano clearly seen.
Ocean sediments trapped in subducted ophi-olites.
Whangarei Falls over compound basaltflows.
Cretaceous sediments on a wave cut pl-form.
Geyser pools at Hells Gate Thermal
14 GA Magazine of the Geologists Association Vol. 4, No. 2,
In February, 2003 seventeen Geologists Association travellersescaped from the snowstorms sweeping across Britain to embarkupon the first GA field excursion to Oman. Now there is a furtheropportunity to see something of the amazing geology of this beau-tiful Middle Eastern country on a special GA field trip in January,2006. Our leader will be Dr. Omar Al-Ja aidi, President of theGeological Society of Oman, who co-led the previous GA trip andhas fully revised the itinerary.
So what will be seen? After a day studying the geologyaround Muscat, including a visit to the remarkable SultanQuaboos Grand Mosque, participants will travel north-west alongthe Gulf of Oman coast to the Sohar area and then inland toNizwa. We will continue south along the Oman Mountains to Surand Wahiba before returning to Muscat. The journey is speciallydesigned to include cultural and traditional aspects of the country.
The rocks are dominated by the Oman ophiolite - a huge raftof Tethyan oceanic lithosphere with associated deep-sea sedi-ments that has been pushed (obducted) some 400km over thepre-Permian continental shield and Permian-Cretaceous Tethyanshelf carbonates. We will examine the ophiolite and associatedrocks, working through the entire sequence, from the upper partof the mantle with its Harzburgites and Dunites, to the top of theoceanic crust represented by extrusive basalts with radiolariancherts. One of the highlights of the whole trip will surely be to standastride the Moho at Wadi Abyad! Yet another is certainly thesuperb outcrop of Geotimes pillow lavas in Wadi Jizi.
Post-obduction deposits include Maastrichtian conglomer-ates, which have yielded dinosaur bone fragments, and cyclicalLower Tertiary shallow marine sediments (limestones and evapor-ites), which yield abundant nummulites and other foraminifera.Other locations visited will include such diverse geology as pre-Cambrian tillites, hot springs and the Jurassic-Cretaceous bound-ary - something for everyone!
The rocks and structures we see will be discussed in theregional context of Middle Eastern plate movements and the open-ing and closing of the Tethys Ocean, including the concept ofobduction - the implications of the process and how quickly ithappened. The economic importance of the country - and indeedregion as a whole - will also be considered. Oman has great min-eral wealth - copper has been mined since the Sumerian periodsome 5,000 years ago - and, in particular, great oil wealth. It issomewhat surprising to learn that much of the oil in Oman derivesfrom Pre-Cambrian source rocks!
The combination of mountains, rock formations and desertclimate has led to the formation of some stunning landscapes,making this a very special part of the world. It is quite exciting tolook down at Oman s own Grand Canyon (especially if there is astrong wind blowing) at the summitof Jebel Shams, the highestmountain in Oman. And to add even more excitement to the trip,a night can be spent under the stars among the seif and barchandunes at Wahiba, which has its own unique Quaternary history,ecology and Bedu way of life.
It is difficult to believe that only 35 years ago Muscat wasthe world s smallest capital, with just 600 inhabititants and we willvisit some of the country s historical and cultural sites - the fortsat Nizwa and Jabrin, the beehive tombs of Jebel Misht (reputed-ly 5,000 years old), farms controlled by traditional falaj irrigationsystems, and the dhow shipbuilding in the boatyards of Sur. Anopportunity to see green turtles hauling themselves up the beachat Ras al Junayz to lay their eggs has also been arranged - a noc-turnal experience not to be missed!
PILLOW TALK - OMAN REVISITED
Above: the hot springs at Hammam Ali.
Below: Sumerian beehive tombs of Jebel Mischt,Jebel Akdhar in the distance.
GA Magazine of the Geologists Association Vol. 4, No. 2, 2005 15
OMAN REVISITED
A report of the 2003 GA Field Excursion to Oman, by ClPorteous, appeared in the June, 2004 G.A. Magazine (VoNo.2). An article on the building stones of the SultanGrand Mosque appeared in the same magazine.
The Geologists Association has now arranged a fieexcursion to study the geology of this fascinating couvisit cultural and historical sites. The excursion, wirevised itinerary, will be led by Dr. Omar Al-Ja aidi -ist colleagues from the Geological Society of Oman in 17th-29th January, 2006. Please contact Sarah StaffordGA office for full particulars and booking forms.
Above: The Moho atWadi Abyad extendsdiagonally down thewadi side, separatingdarker, greener colouredmantle from orange-tinged crust.
Above right: The spec-tacular outcrop ofGeotimes pillow lavas atWadi Jizi.
Right: . Oman s GrandCanyon at Jebel Shams.
GA Magazine of the Geologists Association Vol. 4, No.16
Winter weather is no deterrent to Rockwatchevents throughout the country as our recentevents programme attests. The winter/earlyspring events are part of our out-reach pro-gramme where we encourage and enthusethe public about the far-reaching impacts ofthe Earth sciences on our daily lives and havefun with a range of Rockwatch activities toillustrate this at the same time. We have had atremendously successful out-reach pro-gramme during the past few months inCambridge, Chester, Keyworth and Lyme Regisas well as events for members at the NaturalHistory Museum Mineralogy Workshop and theMicrofossil Workshop in London.
The Family Fun Day at the SedgwickMuseum in Cambridge attracted nearly 800visitors and it was great to see so manyRockwatch members there. In addition toRockwatch activities, Museum staff ran fossiltrails and quizzes and, for the first time, wehad a mini-conference specially targeted atRockwatchers and their parents, which washugely successful. There were three talks byyoung scientists working at the university onearthquakes, climate change and palaeontol-ogy with time for questions, many of whichproved quite challenging to the speakers! Ouryoung Rockwatchers certainly knew their stuff.
Rockwatch was on the road again inearly March, this time to the GrosvenorMuseum in Chester for a Family Fun Day whichattracted lots of visitors including manyRockwatch members. The Jurassic dioramasand fossil replica making were firm favouritesand shoppers in the busy Chester streets musthave wondered at the vast number of scary,dinosaur filled boxes being carried home byexcited youngsters! We also ran colouringgames for younger children and local geologyidentification activities with colleagues fromthe Liverpool Geological Society.
During National Science Week,Rockwatch joined the British Geological Survey(BGS) in Keyworth to run activities for almost1000 schoolchildren and 100 of their teachers,ending the week with a Family Fun Day open
to the public where many Rockwatch mem-bers joined in the fun. The Family Day was afirst joint public event for Rockwatch and BGSat Keyworth. Together we ran a huge numberof new and familiar activities that kept us real-ly busy with hundreds of visitors. BGS also rantours behind the scenes to the Core Storeand Fossil Museum as seen by AlanTitchmarsh in his recent television programmeBritish Isles: A Natural History . Everyone hadthe chance to meet some real geologists andlearn at first-hand what they do for example,by trying their luck at gold panning, generat-ing an earthquake and identifying fossils ormaking their own replicas or even buying thereal thing from the BGS shop - speciallyopened for the event!
Members events during the winter peri-od included a mineralogy workshop at theNatural History Museum which was a greatsuccess. We owe our thanks to Andy Fleet,Keeper of Mineralogy, for this marvellousopportunity for Rockwatchers and their par-ents to see and handle some of the amazingspecimens including some extraordinary mete-
orites and learn at first-hand about researchgoing on in the department.
The superb Microfossil Workshop inLondon run by Adrian Rundle built on the onehe ran for us last year, so Rockwatchers onthese courses are becoming very skilled atpreparing their own slides and identifying ahuge range of microfossils. This year we dis-covered the secrets of the deep sea ooze col-lected off the coast of Florida on 3rd May 1886at 3.35p.m. precisely! We also sortedandprepared samples from Dog s Bay,Connemara, from the Fleet in Dorset and fromFercourt in France quite an interna-tional collection.It was an excellent day anda fantastic opportunity for Rockwatchers toenhance their micropalaeontological skillsunder expert tuition.
During the school Easter Holidays,Rockwatch joined the Lyme Regis Fossil
Festival, a two-day event that attrac-dreds of visitors to this part of the World Heritage Coast. The Natural HisMuseum staff ran a fossil roadshow an-ogy walks, local dealers had some wonspecimens for sale, a local artist raPainting where children used the locapaint a fantastic Jurassic sea scenRockwatch ran activities, there were walks and activities on the beach. In -ly technological age of the 21st centurwas interestingto observe low-techRockwatch activities where whole fami
ROCKWATCH NEWS
Below: Families working togethermaking Jurasssic dioramas at Lyme
Below: Rockwatch making local news!
Above: Chester Museum, dioramas inthe making.
Above: Andy Fleet explaining thefiner points of meteorite classifto Rockwatchers.
Below: Rockwatchers preparing slidof microfossils.
GA Magazine of the Geologists Association Vol. 4, No. 2, 2005
Below: King s Cave, part of a Quaternary rbeach cut into Permian Sandstone North of
Above: Carboniferous lagoonal mudstones and-
Below: Ordovician pillow lavas exposed in the river bank at North Glen Sannox.
Above: Tertiary tholeiitic basalt dyke cutting Devonian conglom-erates at North Glen Sannox, Arran. A fault has offset the dykeby some five metres.
GGEEOOLLOOGGYY IINN AARRRRAANN
The pictures on this page, and the two on the back page, illustratea few of the many splendid geological features of the Isle of Arran.Details of the geologyare described in the Association s Guide Number32 (2000). An Island well worth numerous and repeated visits.
The pictures here and those on the back page were all provided byJames Deighton - a member of Rockwatch who took them on a field tripto the Island. His report on the visit was a winning entry into the YoungWriters Competition. His reportruns to some 80 pages and includessome forty pictures a few of which are reproduced here. It reviews thewhole of the geological history of the island, gives details of four itiner-aries and reviews igneous, sedimentary and metamorphic featuresencountered as well as features of the landscape and geomorphology.James has been a Rockwatch member for some five years, and has wonthe rock writer, over 12, competition twice, and the over 16 category thisyear. At present, he is workingfor an A level in Geology and hopes to
GA Magazine of the Geologists Association Vol. 4, No. 2, 200518
Making a case for the publication of short field guides capable ofkeeping people happy from, say, Friday to Sunday is fairly straight-forward and is undoubtedly feasible for most of the British Isles.Although most of our usually thicker detailed field guides, with a lit-tle planning, can be suitably dissected to create a 2 or 3 day trip thismeans that a more expensive guide has to be acquired then theappropriate information put together, a task probably requiring someprior knowledge of the ground to be visited. Most of us probably donot have the inclination to do that and would prefer the job to bedone by someone else. The time factor is , no doubt, also importantwhen it comes to how much of it we can spare for such short visits.
There often appears to be a plethora of pamphlets coveringshort walks with geological and geomorphological content but thesetend to come to ones attention only when visiting a particular area.There are a relatively large number of pamphlets, booklets and otherguides dealing with the world famous Dorset Coastal area, parts ofDerbyshire and The Lake District but elsewhere in the British Islescoverage is patchy. When you spot them in the local bookshops andnewsagents they are usually quite cheap but tend to be very variablein quality, some being very well produced with high quality accurateinformation and well-illustrated, others much less so. Some areproducedfor the casual holidaymaker or country walker pointing outand illustrating some of the main geological features en route, com-monly in a very attractive way. Others are more detailed in approachand probably more suitable for people already knowledgeable aboutcertain aspects of geology.
The standard Geologists Association field guides so far can besaid to belong to the second category carrying considerable techni-cal detail about many excursions within a given area or region. Thisis because the guides have been designed to suit the interests andbackground of a wide range of customers, including professional earthscientists of all types some regularlyleading field parties for a weekor more, postgraduates, undergraduates, school teachers and lastbut by no means least the numerous enthusiastic and knowledgeable
amateurs spread throughout this country. This higher l-sistency of approach over the years is a particular ni-archy of field guides originating in Britain which thewith some success over the last forty or fifty years. 65 GA guides have been published, not counting reprinteditions. Of course, guides of high calibre have emanageological sources such as the Scottish societies and Geological Survey, but not quite as many as from the G
For several years now there have been discussions GA along the lines of producing quality technical guidareas designed to cover enough ground for worthwhile s2-3 days. As a consequence we published The Origins ofStratigraphy, 1719-1801 by John Fuller as a trial run this has received good reviews. It is a weekend historexcellence to the Bath area and the early strivings ofand his predecessor John Strachey. Now we are in procepublication of a short guide to the geology of the WatSomerset authored by Eric Robinson, who has led innumeweekend parties around it recently. This will be illusof Eric s clear field sketches and photographs (Figs 1an excellent locale, with beautiful coastal and inlanda quick overview of fossiliferous Liassic strata, boneSandstone red beds carrying gypsum veins and nodules aPleistocene gravels.
The guiding principle, if you will excuse the pun,concept of producing week-end guides is that they willquality of content suitable for all levels of our membsold as cheaply as possible, much less than our usual Needless to say the success of any proposed short guidthe availability of willing authors, both amateur and especially those who can perceive and know suitable ar-tions where there is a distinct gap in guide literatursome time or other, have been to some locations, it miprolonged series of sea-cliffs or exposures along an i-ment, and wished there was an informative geological g
WEEKEND FIELD GUIDES J. T. Greensmith
Folded and Faulted Liassic Clays, Helwell Bay, Watchet
All the followingare available inperson or by postfrom Geologists Association Burlington House,Piccadilly, London, W1J0DUAll the prices showninclude post and pack-ing (Overseas add £1).
At £13.00 (GA Members)£17.00 (Non-members)2 The Lake District (1990)22 Dorset Coast (1993)At £11.00 (GA Members)£15.00 (Non-members)7 Manchester Area(1991) 26 ThePeak District (1999)27 South Shropshire(2002)32 Isle of Arran(2000) 34Yorkshire Coast (2000)44 Late Precambrian,
Scottish Highlands &Islands (1991)
46 Isle of Man (1993) 47 Coastal Landforms of
West Dorset (1992)49 Tenerife (2003)50 Southern Cyprus(1994) 51 TheIsland of Bute (1995) 54
Aberystwyth District (1995)
55 Early Cretaceous Environments of the Weald (1996)
56 Castleton Area,Derbyshire (2000)
59 The Geology ofHadrian s Wall (1997)
60 The Isle of Wight(1998)61 Geology of the Western
Front 1914-1918(1998)64 D-Day Landings (2003)At £8.50 (GA Members)£11.00 (Non-members)63 East Midlands (2003)At £6.00 (GA Members) £7.00 (Non-members)19 West Cornwall (1994)41 Jersey (2003)42 Mallorca (1990)43 Costa Blanca (1990)62 Lanzarote (2000)65 Origins of Stratigraph
(2004)At £5.00 (Members) and£6.00 (Non-Members)53 Eastern and Central
Jamaica (1995)At £4.00 (GA Members) £5.00 (Non-members)10 North Cornwall, Budeto
Tintagel (1998)
GEOLOGISTS ASSOCIATION
Figure 1, Gypsum veins in New Red Sandstone, MerciaMarls, West Beach, Watchet.
DESERTS OF THEEARTHMichael Martin
Thames & Hudson 2004ISBN 0 500 511942 £35.00 (hardback)
At first glance this is a book for the coffeetable. It is produced in large format and
principally comprises photos taken inthe world s deserts. In his scene-set-ting section at the beginning of thebook Michael Martin, the book sauthor and photographer, explainsthat he spent nearly three years trav-elling through all the deserts of theworld to obtain the material for thiswork. The book comprises 372 pagesand many of the 271 colour photo-graphs fill one or two full pages. It isprimarily, therefore a photographicessay but the reader should notunderestimate the informative, ifbrief, accompanying text.
The introduction sets out todefine what a desert is and todescribe the types of desert and whythey occur. Successive chapters thendescribe the deserts of each conti-
nent; Asia, Australia, America and Africa.Each of these chapters comprises anoverview followed by coverage of eachdesert area in that continent. Theoverview is particularly useful, comprisinga regional map with the desert locationsclearly illustrated. The text and photo cov-erage spans landscape, peoples and cul-ture and while the photos are superb,those of technical interest to the geologist
are limited to some 15% of the whole.Following the regional chapters t
follows a chapter on desert landscapeFor me, and probably for the geologisamongst the readers, this is the most -esting part of the book and again, whthe text is general in nature, the phmagnificent. Two final chapters coveand Survival in the Desert, with sectdesert plants, desert wildlife and depeople, and Exploring the Deserts.Included rather randomly, are specialarticles by Professor Klaus Giessner Changes in the Saharan Climate andLandscape, by Dr Ulrich Wernery on ThCamel and the Desert and by ProfessorStefan Dech on Desert Exploration fromSpace.
So where does this book fit in togeologist s library? If you need a rbook to quickly show the locations ofdesert regions on a worldwide or contby continent basis, if you wish to sephotographed examples of desert land-scapes, or if you need a basic summardesert characteristics this book may p-vide it. But, for the serious studenare more authoritative texts, if less -al. If you would like a book for youtable which has a superb collection o-
GA Magazine of the Geologists Association Vol. 4, No. 2, 200520
DUNWICHThe geology of Suffolk s lost city
It is difficult to imagine, looking at the sleepy cluster of Victorianhousesthat are there now, just how dramatic the loss of Dunwichwas. For standing on the cliff top, looking eastwards across theNorth Sea, all that remains of what once lay within the city wallsis one gravestone. The rest of the city has crumbled into the sea.
The Saxons had settled by the early 5th Century, making useof the natural sheltered harbour of the Dunwich estuary. St Felixarrived in 630 to bring Christianity to East Anglia, became the firstbishop of Dunwich, so setting the trend for the establishment ofreligious foundations in the city, and died there. The city and portflourished and saw further huge growth following the NormanConquest, becoming rich and prosperous.
By the early 12th Century Dunwich was the sixth greatesttown in England and one of the country s most important ports,with a huge fleet of warships, fishing vessels and cargo vesselstrading throughout Scandinavia and continental Europe. The cityhad its own charter, mint and merchants guild, a preceptory of theKnights Templar and one of the first windmills in Britain.
Coastal processes destroyed all this. Erosion, mentionedeven in the Domesday Book, has always been a problem. The cliffsof poorly consolidated sands and gravels of the Westleton Beds(Norwich Crag Series, 1.6Ma), coupled with violent easterly galesand longshore drift mean that the coast has retreated at an ever-age rate of 1m every year for at least 2000 years. Particularlysevere were the storms of 1287 and 1328 - which togetherdestroyed nearly a quarter of the city. The harbour had its ownproblems, frequently and ultimately becoming blocked by thegrowth of a shingle spit across the entrance. The city never recov-ered. By 1400 over half the buildings had been lost and the peo-ple, together with the merchants and industries, moved away.
However, remnants of the city still survive. The LeperChapel, previously a Saxon church, is all that remains of St. JamesHospital, founded by Richard I at the end of the C12th. It was builtaway from the city itself - the church ordered that lepers were notallowed to live in towns for fear of the disease, probably import-ed during the Crusades. The hospital was also used for the poor,sick and aged, and the last leper died in 1536. The chapel was lastused in 1685.
The stylish Norman architecture can still be clearly seen,with fine carved Caen stone windows and arches. Of particularnote, seen in the north wall and east end, is the fine decorativecontrast between imported pale Caen limestone and darker brownlarge Septaria, some badly weathered, from the London Clay ofsouth Suffolk. Elsewhere, beach flints and other materials areused, partly for restoration and conservation of the ruin.
One of two former monasteries, Greyfriars was built in sevenacres just outside the city wall, completed in 1307 and was one ofEast Anglia s most important Franciscan centres. The monasterywas originally foundedin 1228 on an earlier site which was severe-ly damaged in a storm in 1287 and then lost. It became a ruinafter the Dissolution in 1538 and masonry was carried off bybuilders for use elsewhere. Later buildings on the site used recy-cled stone and brick, but were mostly demolished by 1815. Themonastery was enclosed by a high wall, using materials recycledfrom churches and chapels threatened by the sea, with the mainarched entry gate on the Westleton Road. They contain the sameflint, limestone, septaria and many of the exotics seen in St.James Church. However, part of the eastern section is composedalmost entirely of blocks of Pliocene (3.6Ma) Coralline Crag, a softsandy limestone from the Aldeburgh/Orford area to the south.
After nearly 60 years without a parish church, St. JamesChurch was built on the site of the former leper hospital in 1830to a simpleneo-classical design by Robert Appleton. A mass grave
Below:The eastern end of the ruin of the Leper ChNote the decorative contrast between the pale Cae-stone, often finely carved, and the dark Septaria
The ruin now left on the siteof Greyfriars monastry.
Over 20 different types of building stone can be found in thechancel alone. They are mostly local flint with white Caen lime-stone around windows and doors. However, about one third of theroughly dressed stones used are exotics and include red, pink andwhite granite, black dolerite, basalt and gabbro, white and pinkquartzites, gneiss, slate, gritstone, several types of sandstone andlimestone, chalk and others.
The same rock types can be seen in the other walls, but localSeptaria are much in evidence (over 10% of the materials used)with round flint pebbles from the beach. Original Suffolk Whitebricks can be seen in the tower.
Most of these building stones are recycled from the formerleper hospital and previous Dunwich buildings lost to the sea.Some, such as the Caen limestone, were imported from Franceduring Norman times, and much stone was at that time ballastused by shipping.
A traditional locally made Suffolk pavement floor can be seeninside the church. In the south-east corner of the church-yardstands the last buttress of All Saints Church, the last survivor ofDunwich s medieval parish churches. The final part of the towerwas lost to the sea in 1922, but the north-west buttress was savedand moved to its present site. Of note is the finely dressed che-querboard pattern of limestone and flint used in construction.
There is further evidence of Dunwich s origins and history tobe seen in a gentle stroll around the village - the small museumhas a splendid model of the old city. The cliff section will further appealto geologists.And at the end of the long morning s walk, a fineplate of fish and chips washed down, of course, with tea canalways be had in the cafØ!
Thanks to a grant from English Nature, GeoSuffol(Suffolk RIGS) has just published a new leaflet the geology of Suffolk s lost city to add to iseries. It is available free to visitors at locaTourist Information Centres, libraries and muse-ums.
Dunwich Forest was planted by the ForestryCommission in 1929Minsmere bird sanctuary was created by the RSPBin 1948Westwood Marshes is a National Nature ReserveThe National Trust acquired Dunwich Common in1968
Top right: One of the arched entrances to Greyfriars.Note the fine flint work with contrasting Caen limestone.Bottom right: Some of the many different rock-types tobe found in the chancel of St. James Church.
Below: One of the Medieval arched entrances with theruin beyond. The ruin now left on the site of Greyfriarsmonastry.
GA Magazine of the Geologists Association Vol. 4, No. 2, 2005 22
Fossil Fest I Field Meeting -New LattonQuarry
Saturday 5th March dawned cold and withthe promise of more snow. However,despite the weather some 30 GA mem-bers convened in New Latton quarry onthe edge of the Cotswold Water Parkbetween Swindon and Cirencester.Fortunately apart from a few sleet show-ers the weather was relatively kind to usfor most of the day. The meeting wasorganised by Dr Neville Hollingworth ofNERC (now at the Centre for Ecology andHydrology(CEH) Dorset ) assisted by DrJason Hilton of Birmingham University.
As those who attended his lecture onCallovian Calamari will know Nev is anexpert on the geology of this area and hefirst gave the party a brief introduction tothe rocks exposed in the quarry. NewLatton exploits Pleistocene gravels, hereforming part of the Northmoor Terracedated at 50,000 years bp. These weredeposited during the last interglacial anda basal lag horizon yields remains ofmammoth, bison and deer indicating acool climate.
The floor of the quarry also exposes sec-tions through the Middle Jurassic,Callovian, Kellaways Clay , Kellaways Sandand Lower Oxford Clay which dip at c1.5o to the south. These are between164.7 and 161.2 million years old(Gradstein et al 2004) and are richly fos-siferous with abundant ammonites,belemnites, bivalves and brachiopods.Fortunately Nev prevailed on one of thedigger drivers to turn over some freshmaterial for us and after his talk the partydispersed around the quarry and veryquickly found numerous well preservedspecimens of Cadoceras, Proplanulitesand Kepplerites as well as ubiquitousGrypheas. A nice mammoth tooth wasalso found by John Evans.
Several members also visited a smallgravel pit about ten minutes walk awaywhich exposesgravels overlying OxfordClay. However, apart from one largemammal tooth (?rhinoceros?) no findswere reported.
Towards the end of the afternoon theweather deteriorated and the party beganto disperse but not before most had col-lected some very nice specimens. Ourthanks to Nev and Jason for organisingthe meeting and to Cotswold AggregatesLtd for permission to enter the pits. Don t
Above: John Evans, PastPresident of the Association witha mammoth tooth.
Right: Fresh exposure to order.
Diane Clement andJanna Roberts holding a
Busy Members finding ammonites in the quar-
Pete Green with a
Field MeetingLeader NevilleHollingworth intypicalpose.
GA Magazine of the Geologists Association Vol. 4, No. 2, 2005 23
In the ProceedingsIn the followingparagraphs, theEditor reviewsforthcoming arti-cles in theProceedings ofthe GeologistsAssociation.
The appearance ofPresidential Addressesin the Proceedings is alwaysmost welcome (sadly, notall of them make the transi-tion from oral communica-tion to an article in our
journal of record). William French has (by, I suspect, an hero-ic effort) found the time around editing and producing GA towrite up his thoughts on Why concrete cracks: Geologicalfactors in concrete failure. We are all familiar with concrete,it has literally, been around since Roman times in Britain, hold-ing together Hadrian s Wall as well as innumerable castles andcathedrals from Norman times onwards which still survive.Modern portland cement was introduced in the mid-nineteenthcentury. Today, some 12 million tons of cement are used annu-ally and underpin our modern constuction industry. We are sofamiliar with it, that perhaps one no longer takes consciousnotice of its near-ubiquitous presence fence posts in the gar-den, motorway bridges, car parks, offices, schools, hospitals,supermarkets and countless other buildings. However, willthese modern constructions last as long as has Hadrian s Wall?Perhaps not only in the last few years has it been realised thatparticular types of stone which forms the aggregate, and whichmakes-up the bulk of the concrete, can gradually react with thecement paste and only after some twenty to fifty years, depend-ing on circumstances, do the results become evident: crackingand swelling of the concrete results, critically weakening, andperhaps even deforming, the structure. This article explains thegeological and environmental factors which underlie this poten-tial for major deterioration and what steps can be taken to avoidit. Next time you are stuck in a traffic-jam, with only the sup-ports and underside of a concrete overpass to pass the timecontemplating, this article will provide you with much food forthought.
A number of papers have appeared on the geology of theChannel Islands over the years. Edward Rose now provides uswith an admirable account of The first hydrogeological andgeological maps of Jersey, Channel Islands: work byWalter Kl pfel in 1942 and Richard Nelson c. 1928.Curiously, both maps, which the author has unearthed archivesin Britain and Germany, have their origins in military-geology.Lieutenant (later Major-General) Nelson was an officer in theRoyal Engineers and Kl pfel was a military geologist during theoccupation of the Cannel islands in World War II. Nelson s mapappears to be the first truly geological map of the island.Kl pfel s task was to view the geology through the prism of mil-itary requirements to aid the location of sites for gun-emplacements, observations towers, storage points, and ofsources of aggregate, sand and water for construction. Rosedescribes the backgrounds of these two men and the results oftheir endeavours.
On the occurrence of a mollusc fauna in the Red Crag
pebblebed from Mason s Pit, Great Blakenham, Suffolkby Roger Dixon describes the first occurrence of an inmollusc fauna from that location at that horizon.
The appearance of three Field Reportsin this issue is alsowelcome: Iain Williamson describes a meeting by the Lancgroup in Lower Kingsdale and Chapel-le-Dale, Ingleton,North West Yorkshire on 9 August 2003; Roger Dixon reporton the Coastal Suffolk Crag week-end,23-25 April 2004;and in Romney Marsh; its churches and geology,JohnPotter describes a trip to inspect the building fabricchurches situated either on the marsh or its fringes. -titative studies of the makeup of the building stones,with his knowledge of church architecture, have enablehim todetermine the sources and timing of the use of buildinin the area. All three trips have plenty to interest Gwho wish to follow in the tracks of previous field par
Philip Commander provides us with an Essay Reviewof200 Years of British Hydrogeology (edited by J.D. Mather),a volume on the history of the provision of a vital republic water supplies - which, like concrete, one tendtake for granted. He describes the work of people sucWilliam Smith, who first elucidated the principles of sinking; the engineer Robert Stephenson, whose experti-vided the water-pumping engines; the London physician Snow, who first showed that diseases could be transmitted viacontaminated well-water; Joseph Lucas, the first profe
Above: View west of North Geln Sannox showing grey grits and schists in the forground and gran-tance.Below: An exposure on the North Sannox shore. A cornstone layer at the bottom is overlain by
