D. Submarine geology and geophysics

560 OLR(1986)33(7)

16(12):493-497. Inst. de Geol. du Bassin d'Aq- uitaine, Univ. de Bordeaux I, 351, 33405 Talence, Cedex, France.

86:3813 Chapman, D.V., 1986. The distribution of metals in

sewage sludge and their fate after dumping at sea. Sci. total Environment, 48(1-2): 1-11.

A review of the literature concerning the distribution of toxic metals in sewage sludges suggests that in most sludge types metals are bound to small particles (<10 ~tm) consisting mostly of organic matter. Evidence for the fate of sludge particles and their associated metals after dumping at sea is conflicting; recent work suggests little of the metal is lost to solution. Prior to settling, organic particles are available to planktonic filter-feeding organisms, whereas the larger, denser fraction of the sludge settles more rapidly and is available to benthic organisms. Dept. of Zool., Univ. Coll. London, Gower St., London WC1E 6BT, UK.

86:3814 Falconer, R.A., 1986. Water quality simulation study

of a natural harbor. [Influence of nitrogen discharge from a sewage treatment facility.] J. WatWay Port coast. Ocean Engng, Am. Soc. civ. Engrs, 112(1): 15-34. Dept. of Civ. Engrg., Univ. of Birmingham, P.O. Box 363, Birmingham B15 2TT, UK.

86:3815 Hallacher, L.E., E.B. Kho, N.D. Bernard, A.M.

Orcutt, W.C. Dudley Jr. and T.M. Hammond,

1985. Distribution of arsenic in the sediments and biota of Hilo Bay, Hawaii. Pacif. Sci., 39(3):266- 273. Univ. of Hawaii, Div. of Nat. Sci., 1400 Kapiolani St., Hilo, Hawaii 96720, USA.

86:3816 Kjolholt, Jesper, 1985. Occurrence of organophos-

phorus compounds in polluted marine sediments near a pesticide manufacturing plant. Chemo- sphere, 14(11-12):1763-1770. Natl. Agency of Environ. Protection, Centre for Terrestrial Ecol., Gyden 2, DK-2860 Soborg, Denmark.

86:3817 Sanders, J.G., 1985. Arsenic geochemistry in Ches-

apeake Bay: dependence upon anthropogenic inputs and phytoplankton species composition. Mar. Chem., 17(4):329-340. Acad. of Nat. Sci., Benedict Estuarine Res. Lab., Benedict, MD 20612, USA.

C240. Corrosion

86:3818 Beccaria, A.M. and G. Poggi, 1985. Analysis of

aluminum-brass corrosion products in seawater and in chloride solutions. Analyt. Letts, 18(A18): 2259-2275. Ist. per la Corrosione Mar. dei Metal., Cons. Naz. delle Ricerche, Via Mercan- zia, 4-16123 Genova, Italy.

D. SUBMARINE GEOLOGY AND GEOPHYSICS

D10. Apparatus and methods

86:3819 Kalra, A.K., 1986. Velocity analysis for feathered

marine data. Geophysics, 51(1):190-191. Amoco Production Co. Intl., P.O. Box 3092, Houston, TX 77253, USA.

86:3820 Kim, H.-J., S.-J. Han, S.-R. Kim and H.-S. You,

1985. Application of homomorphie deconvolution

to seismic data processing. Part 1. Ocean Res., KORDI, 7(1):49-55. (In Korean, English abstract.) Geol. Oceanogr. Lab., KORDI, Seoul, Korea

86:3821 Laster, S.J., 1985. The present state of seismic data

acquisition: one view. Geophysics, 50(12):2443- 2451.

The state of seismic reflection prospecting (at land and sea) in the mid-1980s is briefly reviewed,

OLR (1986) 33 (7) D. Submarine Geology and Geophysics 561

focusing on aspects considered most important by the author. These include hardware (more data channels), digital telemetry, positioning (satellites), S-wave sources, and 3-D seismic recording. Mobil Res. and Develop. Corp., P.O. Box 819047, Dallas, TX 75381, USA. (fcs)

86:3822 Lowe, D.C. and W.J. Judd, 1985. Bomb conversion of

CO 2 to graphite for radiocarbon measurement by tandem accelerator mass spectrometry (TAMS). Int. J. appl. Radiat. Isotopes, 36(12):939-942. Inst. of Nuclear Sci., DSIR, Private Bag, Lower Hutt, New Zealand.

86:3823 Mitchell, J.F. and R.J. Bolander, 1986. Structural

interpretation using refraction velocities from marine seismic surveys. Geophysics, 51(1): 12-19.

A simple exploration scheme can be set up on a personal computer for routine use. Using refraction first arrivals, shallow sediment velocities are com- puted and mapped; contoured velocity patterns allow structural interpretations. The method requires only that the subsurface structure be relatively shallow and is particularly useful in areas where seismic reflection data are poor. Belco Petrol. Corp., 1 Dag Hammarskjold Plaza, New York, NY 10017, USA. (sir)

86:3824 Noponen, Ikka and Joe Keeney, 1986. Attenuation of

waterborne coherent noise by application of hyperbolic velocity filtering during the tau-p transform. Geophysics, 51(1):20-33. Tech. Div., Geosource Inc., 2700 Post Oak Blvd., Suite 2000, Houston, TX 77056, USA.

D40. Area studies, surveys, bathymetry

86:3825 Griffiths, G.A. and G.P. Glasby, 1985. Input of

river-derived sediment to the New Zealand continental shelf. I. Mass. Estuar. coast. Shelf Sci., 21(16):773-787.

The input of river-borne sediments to the continental shelf has been calculated for all the major rivers and basins in New Zealand. South Island yields 284-+40 × 10 ~ tonnes per year of sediment from a land area of ~153,000 km 2 and North Island yields 105 + 9.4 × 106 tonnes per year from a land area of ~115,000 km 2. Particularly high discharges are noted off the west coast of South Island and east coast of North Island and result in higher offshore

sedimentation there. The sediment yield from South Island is amongst the highest recorded. North Canterbury Catchment Board, P.O. Box 788, Christ- church, New Zealand.

86:3826 Mougenot, Denis, 1985. Progradation on the Por-

tuguese continental margin: interpretation of seismic facies. Mar. Geol., 69(1-2): 113-130.

The inner shelf in front of river mouths is covered by Holocene deltas, the outer shelf is built out by progradation associated with paleovalleys, and the Algarve upper continental slope is overlain by contour ridges. On the shelf, progradation may be easily explained by the supposition of a stability level at which sedimentary particles come to rest; the sigmoid or oblique configuration of the prograding layers is related to margin subsidence. Disconti- nuities between prograding sequences are determined by changes in water depth. Univ. P. et M. Curie, B.P. 48, 06230 Villefranche-sur-Mer, France.

86:3827 Nawar, A.H., 1981. Bottom sediments and topog-

raphy of the Gulf of Suez. Bull. Inst. Oceanogr. Fish., Arab Repub. Egypt, 7(3):484-504.

Bottom grab samples show a constant light mineral fraction pattern but a variable heavy mineral fraction that divides the gulf into four provinces controlled more by source rock than topography. The provinces were characterized by different abundances of epidote, opaque-pyroxene, hydrated iron oxide and amphibole minerals. Inst. of Oceanogr. and Fish., Alexandria, Egypt. (gsb)

D 6 0 . Geomorphology (fans, canyons, etc.)

86:3828 Gershanovich, D.E. and V.V. Fedorov, 1985. Marine

landscape studies---a new approach in the science about the nature of the ocean. Izv. Akad. Nauk SSSR, Ser. Geogr., 5:5-14. (In Russian.)

D70. Coasts, beaches, marshes

86:3829 Amos, C.L. and D.C. Mosher, 1985. Erosion and

deposition of fine-grained sediments from the Bay of Fundy. Sedimentology, 32(6):815-832.

Field studies and a flume experiment with undis- turbed sediment show that intertidal erosion resis- tance is largely a function of subaerial exposure, and

562 D. Submarine Geology and Geophysics OLR (1986)33 (7)

that sediment erosion can't be defined by one coefficient. In comparison to the direct measurements reported here, the Krone method overesti- mated sedimentation of suspended material by 29%, while settling tube methods underestimated particle settling by an order of magnitude. Bedford Inst. of Oceanogr., P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada. (gsb)

86:3830 Aubrey, D.G. and R.M. Ross, 1985. The quantitative

description of beach cycles. Mar. Geol., 69(1- 2):155-170.

A quantitative method, which uses dominant cycles in temporal eigenfunctions to construct profiles representing the energetic portions of beach cycles, offers a means for objectively discriminating energetic beach cycles, and a concise representation for modeling and prediction. An analysis of five sets of beach profile data from Torrey Pines Beach (southern California) provides an example of the sequential development of bar and berm during a beach cycle, using only first and second eigenfunctions and mean profile. WHOI, Woods Hole, MA 02543, USA. (hbf)

86:3831 Dalrymple, R.A., R.B. Biggs, R.G. Dean and Hsiang

Wang, 1986. Bluff recession rates in Chesapeake Bay. J. WatWay Port coast. Ocean Engng, Am. Soc. civ. Engrs, 112(1):164-168. Dept. of Civ. Engrg., Univ. of Delaware, Newark, DE 19716, USA.

86:3832 Deigaard, Rolf, Jorgen Fredsoe and I.B. Hedegaard,

1986. Suspended sediment in the surf zone. J. WatWay Port coast. Ocean Engng, Am. Soc. civ. Engrs, 112(1): 115-128.

Close to the seabed, turbulence is dominated by the wave-boundary layer, which determines the amount of suspended sediment very close to the bottom. Away from the bottom, the main contribution to turbulence intensity originates from the surface- generated turbulence due to wave breaking, described by application of the transport equation for turbulent kinetic energy. The production of kinetic energy is estimated from the energy loss in a hydraulic jump. The vertical distribution of suspended sediment is obtained from the diffusion equation. Danish Hydraulic Inst., Agern Alle 5, DK-2970 Horsholm, Denmark.

86:3833 Dolan, T.J. and R.G. Dean, 1985. Multiple longshore

sand bars in the upper Chesapeake Bay. Estuar. coast. ShelfSci., 21(5):727-743. U.S. Army Corps

of Engineers, Box 2711, Los Angeles, CA 90053, USA.

86:3834 Donn, T.F. and M.R. Boardman, 1986. A profiling

method for measuring erosion and accretion of intertidal rock surfaces. J. coast. Res., 2(1):69-73. Dept. of Geol., Miami Univ., Oxford, OH 45056, USA.

86:3835 Finkelstein, Kenneth, 1986. Backbarrier contribu-

tions to a littoral sand budget, Virginia eastern shore, USA. J. coast. Res., 2(1):33-42. VIMS, Gloucester Point, VA 23062, USA.

86:3836 Had~ija, Olga, Mladen Jura~ir, Marija Lui~, Maja

Tonkovi~ and Biserka Jeri~evir, 1985. The carbohydrates in relation to mineralogic and granulometric composition of surface sediments in the Karst Estuary (River Krka Estuary, Yugo- slavia). Estuar. coast. Shelf Sci., 21(5):701-709. Ruder Boskovic Inst., P.O.B. 1016, 41001 Za- greb, Croatia, Yugoslavia.

86:3837 Hardisty, J., 1985. A note on negative beach slopes

and flow asymmetry. Mar. Geol., 69(1-2):203-206. Dept. of Geogr., Royal Holloway and Bedford New College, Egham, Surrey TW20 0EX, UK.

86:3838 Kershberg, L.B., A.A. Ryanzantaev, L.G. Gus'kov,

V.G. Shmulev and Yu.A. Naumov, 1986. Sub- merged shorelines ont-continental shelves of the Sea of Japan and Sea of Okhotsk, USSR. J. coast. Res., 2(1):61-68.

The irregular but progressive development of the latest postglacial transgression contains several well-defined stages and phases recorded by shoreline features that include distinctive relief forms and complexes of littoral, marine, and lagoonal sediments. Comparison of submerged shorelines lying on the continental shelf in this region suggests that their common formation is related to an irregular (put- sating) rise of global sea level at the end of the Late Pleistocene and continuing into the Holocene. Differences in hypsometric positions of similarly aged shorelines in different regions and the formation of additional shorelines at intermediate levels in certain areas are assumed associated with neotec- tonic movements. Far Eastern Geol. Surv., Vladi- vostok, USSR.


86:3839 Kobayashi, Nobuhisa and Demet Aktan, 1986.

Thermoerosion of frozen sediment under wave action. J. WatWay Port coast. Ocean Engng, Am. Soc. cir. Engrs, 112(1):140-158. Dept. of Civ. Engrg., Univ. of Delaware, Newark, DE 19716, USA.

86:3840 Kostaschuk, R.A., 1985. River mouth processes in a

fjord-delta, British Columbia, Canada. Mar. Geol., 69(1-2): 1-23.

River mouth processes are directly related to the large tidal range (3.9 m mean, 5.9 m large) which changes the location and nature of distributary mouths producing distinct high- and low-tide outlets. Frictional forces dominate at high tide as the effluent disperses through five dynamic zones producing a radial bar. During low tide, frictional, inertial and buoyant forces and an internal hydraulic jump control the development of six dynamic zones and a lunate-middle ground bar. Dept. of Geogr., Univ. of British Columbia, 217-1984 West Mall, Vancouver BC V6T IW5, Canada.

86:3841 Leatherman, S.P. and R.E. Zaremba, 1986. Dynam-

ics of a northern barrier beach: Nanset Spit, Cape Cod, Massachusetts. Geol. Soc. Am. Bull., 97(1): 116-124. Dept. of Geogr., Univ. of Maryland, College Park, MD 20742, USA.

86:3842 Losada, M.A. and J.M. Desirt, 1985. Incipient

motion on a horizontal granular bed in non- breaking water waves. Coast. Engng, Amst., 9(4):357-370.

A criterion for initiation of sediment movement on a horizontal bed under non-breaking waves is established. Bagnold's sediment transport model is used; the energy dissipation rate is related to the length and velocity scales of the large-scale turbulence. Compared with available laboratory results for fine and coarse material over a wide range of particle sizes, density ratios and liquid viscosities, reasonable agreement is obtained. An incipient motion hypothesis based on the development of vorticity is proposed. Dept. de Puertos y Obras Maritimas, Univ. of Santander, Santander, Spain.

86:3843 Okusa, S., 1985. Wave-induced stresses in unsatu-

rated submarine sediments. G#otechnique, 35(4): 517-522.

A simple method to solve the problem of pore pressure and effective stresses induced by harmonic waves in a poroelastic sediment is presented using Biot's equation and a compatibility condition for elasticity. The solutions contain Skempton's pore pressure coefficient B. When the submarine sediment is unsaturated, the wave-induced negative effective normal stresses become greater under the trough of waves. A zone where the in-situ vertical effective normal stress or the in-situ effective mean normal stress becomes zero is formed in a gas-laden sediment under certain wave conditions. The coefficient B plays a role in controlling the wave-induced instability of submarine sediments. Tokai Univ., Japan.

86:3844 Samsuddin, M., 1986. Textural differentiation of the

foreshore and breaker zone sediments on the northern Kerala coast, India. Sedim. Geol., 46(1- 2):135-145. Centre for Earth Science Studies, P.B. No. 2235 Sasthamangalam, Trivandrum 695 010, India.

86:3845 Schwartz, M.L. and B.D. Anderson II, 1986. Coastal

geomorphology of Padre Island, Mexico. Shore Beach, 54(1):22-29. Western Washington Univ., Belling, ham, WA, USA.

86:3846 Seymour, R.J., 1986. Results of cruss.-shore transport

experiments. J. WatWay Port coast. Ocean Engng, Am. Soc. cir. Engrs, 112(1):168-173.

Three sets of field data obtained in the Nearshore Sediment Transport Study (Scripps Beach and Santa Barbara, California; and Virginia Beach, Virginia) are presented here to enable the testing of cross- shore transport models. Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA.

86:3847 Silvester, Richard, 1985. Sediment by-passing across

coastal inlets by natural means. Coast. Engng, Amst., 9(4):327-346. Dept. of Civ. Engrg., Univ. of Western Australia, Nedlands, W.A. 6009, Australia.

86:3848 Vongvisessomjai, Suphat, 1986. Profile of suspended

sediment due to wave action. J. WatWay Port coast. Ocean Engng, Am. Soc. civ. Engrs, 112(1): 35-54.

Profiles of mean and unsteady concentrations are derived from the mass conservation equation using the diffusion coefficient profile adapted from the

564 D. Submarine Geology and Geophysics OLR (1986) 33 (7)

eddy viscosity profile, taking into account changes of the friction factor and boundary layer thickness in the presence of suspension. The theoretical profiles are expressed explicitly as functions of the friction factor, velocity and shear stress profile parameters, and the settling velocity of the sediment relative to the fluid velocity. Analysis shows that the friction factors in the presence of suspension decrease from the sediment-free values in the same manner and magnitude as the von Karman constant. Div. of Water Resources Engrg., Asian Inst. of Tech., P.O. Box 2754, Bangkok, Thailand.

86:3849 Woods, A.J.C. and L.P. Leahy, 1986. The appli-

cability of multiparameter, relative dating techniques to beach ridge correlation in Baja Cali- fornia Norte, Mexico. J. coast. Res., 2(1):1-15. Dept. of Geogr., Kent State Univ., Kent, OH 44242, USA.

Dll0 . Erosion

86:3850 Young, R.A. and Robert Mann, 1985. Erosion

velocities of skeletal carbonate sands, St. Thomas, Virgin Islands. Mar. GeoL, 69(1-2):171-185. Exxon Production Res. Co., P.O. Box 2189, Houston, TX 77001, USA.

D120. Sedimentary processes (deposition, diagenesis, etc.)

86:3851 Compton, J.S. and Raymond Siever, 1986. Diffusion

and mass balance of Mg during early dolomite formation, Monterey Formation. Geochim. cos- mochim. Acta, 50(1): 125-135. Dept. of Geol. Sci., Harvard Univ., Cambridge, MA 02138, USA.

86:3852 Heusser, L.E. and W.L. Balsam, 1985. Pollen

sedimentation in the northwest Atlantic: effects of the Western Boundary Undercurrent. Mar. Geol., 69(1-2): 149-153.

Recent studies of this contour current show that the high-velocity core is characterized by decreased carbonate dissolution, coarse particle size, and improved magnetic alignment of sedimentary grains. Here it is suggested that the high-velocity core of the WBUC also effects palynomorph sedimentation; pollen concentration is lower and the percentage of redeposited pollen grains is higher under this bottom

current. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA.

86:3853 Hirakawa, Hiromitsu and Taisuke Takeishi, 1985.

Measurement of sedimentation potential of seawater. Mer, Tokyo, 23(3):118-122, (In Japanese, English abstract.) Fac. of Engrg., Kagoshima Univ., 1-21-40. Korimoto, Kagoshima 890, Japan.

86:3854 Kim, D.-C., M.H. Manghnani and S.O. Schlanger,

1985. The role of diagenesis in the development of physical properties of deelr-sea carbonate sediments. Mar. Geol., 69(1-2):69-91.

Bulk porosity decrease appears to be related more significantly to depth of burial than to age of strata. Both depth of burial and age, however, are important factors controlling the modal pore diameter; the modification of pore geometry is influenced by the presence of silica. At the three sites studied, shear wave attenuation anisotropy correlates with the velocity anisotropy. Pore orientation, resulting from overburden pressure and other deep-burial diagenetic processes, is an important factor controlling the increase of velocity anisotropy with age and depth of burial; other contributions such as grain orientation and bedding lamination cannot be ruled out. Hawaii Inst. of Geophys., Univ. of Hawaii, 2525 Correa Rd., Honolulu, HI 96822, USA.

86:3855 Rouchy, J.-M., Claude Monty, Catherine Pierre,

M.-C. Bernet-Rollande, Andr6 Maurin and J.-P. Perthuisot, 1985.~Sulfate reduction and formation of diagenetic carbonate bodies in the Middle Miocene of the Gulf of Suez and of the Red Sea. C. r. Acad. Sci., Paris, (S~r. II)301(16):1193- 1198. (In French, English abstract.)

The Middle Miocene gypso-anhydritic formations comprise several morphological types of carbonates: irregular bodies and domes standing out as isolated buttes after selective weathering of sulfates; stratoid carbonate bodies developed in the lower or the upper part of sulfate beds in contact with laminites; carbonate lenses resting on the flanks of diapiric structures, associated with sulfur and oil or bitumen. The formation of most of these highly porous carbonates is interpreted as resulting from diagenetic processes related to bacterial sulfate reduction in the presence of organic rich sediments. Lab. de Geol., Mus. natl. d'Hist, naturelle, 43, rue Buffon, 75005 Paris, France.


86:3856 Witkowski, Andrzej and Stanislaw Musielak, 1982.

Biogenic sedimentary structure in the coastal zone of the Bay of Puck [Poland]. Zesz. nauk. Wydz. Biol. Nauk Ziemi, Oceanogr., 9:31-48. (In Polish, English abstract.)

D130. Sediments (rocks, formations, type, composit ion, etc.)

86:3857 Mazzullo, Jim and Jeffry Crisp, 1985. Sources and

dispersal of coarse silt on the south Texas continental shelf. Mar. Geol., 69(1-2):131-148. Dept. of Geol., Texas A&M Univ., College Station, TX 77843, USA.

86:3858 McLoughlin, R.J. and P.C. Young, 1985. Sedimen-

tary provinces of the fishing grounds of the north west shelf of Australia: grain-size frequency analysis of surficial sediments. Aust. J. mar. Freshwat. Res., 36(5):671-681. CSIRO Mar. Lab., Castray Esplanade, Hobart, Tas. 7000, Australia.

86:3859 Murav'yev, V.I., L.G. Daynyak and D.I. Golovin,

1985. Changes in the composition of glauconite in contact with seawater. Int. Geol. Rev., 27(7):850- 858.

Laboratory investigations reveal problems inherent in the use of the K-Ar ratio in glauconite for absolute dating. Results show that contact of glauconite with seawater results in Fe(II) oxidation and the release of similar interlayer cations. The cation composition in interlayers may change; specifically, up to 15% of the K may be replaced with Na while the Ar content remains unaltered. Inst. of Geol. Sci., Acad. of Sci., Moscow, USSR. (msg)

86:3860 Ramli, Nik, 1986. Depositional model of a Miocene

barred wave- and storm-dominated shoreface and shelf, southeastern Malay Basin, offshore west Malaysia. Am. Ass. Petrol. Geol. Bull., 70(1):34- 47. Oxford Univ., Parks Rd., Oxford OX1 3PR, UK.

86:3861 Schlager, Wolfgang et al., 1985. Data from ODP Leg

101 on understanding of Bahamian slope and basin sedimentology. C. r. Acad. Sci., Paris, (S6r. II)301(15):1141-1145. (In French, English ab-

stract.) RSMAS, Univ. of Miami, Miami, FL, USA.

86:3862 Sorensen, Kai, 1986. Rim syncline volume estimation

and salt diapirism. Nature, Lond., 319(6048):23- 27.

Quantitative studies of salt structures are based on the assumption of a simple relationship between excess sediment volumes and the volumetric growth of salt structures. This assumption is inadequate; instead, the excess volume relates to the volume swept out by the deforming sediment surface and the moving salt/sediment interface. The use of this new basis for volume reckoning is demonstrated, and its implications for waste disposal, hydrocarbon exploration and tectonic subsidence studies are empha- sized. Statoil, P.O. Box 300, N 4001 Stavanger, Norway.

86:3863 Stevens, S.H. and G.F. Moore, 1985. Deformationai

and sedimentary processes in trench slope basins of the western Sunda Arc, Indonesia. Mar. Geol., 69(1-2):93-112.

Structural ridges bound the basins, formed of folded trench strata and bounded on their seaward margins by landward-dipping thrust faults. Deformation occurs across the entire slope; near-surface strata in the shallowest basin are tilted landward and are cut by a recent thrust fault. A progressive increase in the intensity of deformation with depth is evident. A small submarine fan has developed at the mouth of a canyon in the shallowest basin. Local slumping of hemipelagic slope sediment forms a minor contribution to the overall sediment fill. Texaco U.S.A., 3350 Wilshire Blvd., Los Angeles, CA 90010, USA.

86:3864 Syvitski, J.P.M. and C.T. Schafer, 1985. Sedimen-

tology of Arctic Fiords Experiment (SAFE): project introduction. Arctic, 38(4):264-270.

The Geological Survey of Canada's project SAFE (Sedimentology of Arctic Fiords Experiment) is being carried out in a series of fiords situated along the east coast of Baffin Island. SAFE emphasizes the study of the Quaternary history and modem processes of arctic fiord environments. Project partici- pants are interested in evaluating the significance of the comparatively rapid process rates and of the high-resolution sedimentary records that typify these settings. Key objectives: (1) to understand sandur development and the character of the resultant facies, (2) to understand the time-dependent influences of rivers, tides, waves, wind and deep-water


renewal on fiord circulation and sedimentation patterns, and O) to use the geological record of raised marine deposits in establishing Late Quater- nary history within and between fiords. Bedford Inst. of Oceanogr., Box 1006, Dartmouth, NS B2Y 4A2, Canada.

D140. Submarine hydrology (springs, hydrothermal deposits, etc.)

86:3865 Bender, M.L., Andrew Hudson, D.W. Graham, R.O.

Barnes, Margaret Leinen and David Kahn, 1985/86. Diagenesis and convection reflected in pore water chemistry on the western flank of the East Pacific Rise, 20 degrees south. Earth planet. Sci. Letts, 76(1-2):71-83.

The top 1-2 m of the sediment was oxic at all sites. The C/N of the decomposing organic matter is about 106/6.6 while C/P ranges from 106/0.7 to 106/0.25. Total alkalinity rise is greater than predicted by models assuming calcite saturation, suggesting that phases other than calcite are important in the alkalinity balance and control of CaCO3 saturation. Anomalous pore water NO 3- and SiO2 profiles were observed in areas of high heat flow (and inferred upwelling of pore waters through sediments) and low heat flow (and inferred down- welling). Grad. Sch. of Oceanogr., Univ. of Rhode Island, Kingston, RI 02881, USA.

86:3866 Bideau, Daniel, Yves Fouquet and Roger H~kinian,

1985. First occurrence of hydrothermally metamorphosed basalts in the axial graben of the East Pacific Rise, near 12°50"N (Cyatherm-Clip- perton area). Bull. Soc. g~ol. Fr., (8)I(6):905-913. (In French, English abstract.)

A metabasalt sample retrieved from a talus at the foot of an outcrop (2620 m) was altered by contact with hydrothermal fluids ("~300°C). During alteration, plagioclase and titanomagnetite remained intact, olivine was replaced by talc and matrix- pyroxene by Fe-rich chlorite. Smectites occur throughout; pyrite and chalcopyrite are found in the altered outer margin of the sample. The chemical variation between the core and altered rim shows uptake of Si, Ca, and Na by the fluid phase and Fe-, Cu- and Zn- enrichment in the solid phase. IFREMER, Centre de Brest, B.P. 337, 29273 Brest cedex, France.

86:3867 Bowers, T.S. and H.P. Taylor Jr., 1985. An integrated

chemical and stable-isotope model of the origin of

midocean ridge hot spring systems. J. geophys. Res, 90(B14): 12,583-12,606.

An integrated stable-isotope, chemical equilibria and mass transfer computer model in which fresh basalt is added to progressively modified seawater at discrete temperature intervals is used to estimate modifications of seawater and basalt. Calculated hydrothermal solution major element chemistry and basalt changes are~n agreement,g~th midocean ridge measurements, except for pH and solution saturation estimates for greenschist-facies. Dept. of Earth, Atmos. and Planet. Sci., MIT, Cambridge, MA 02139, USA. (gsb)

86:3868 Crane, Kathleen, 1985. The distribution of geo-

thermal fields along the mid-ocean ridge: an overview. Bull. biol. Soc. Wash., 6:3-18.

The distribution of geothermal fields on the midocean ridge system is dependent upon the dynamics of underlying magma bodies. Detailed bathymetric mapping has revealed a quasi-harmonic distribution of topographic highs along spreading ridges. The average distance between highs increases with spreading rate and with distance between transform faults. Recent surveys along the Juan de Fuca Ridge and along the East Pacific Rise have revealed that these highs are geothermally active. On the Juan de Fuca Ridge five thermal fields occur at intervals of 100 kin. On the faster spreading East Pacific Rise four fields were discovered at intervals of 140-160 kin. The fields average 20 km in length along the crests. These axial highs may be produced by diapirs rising from a continuous layer of magma instability and may migrate along the ridge in response to changing plate motion. Lamont-Doherty Geol. Observ. of Columbia Univ, P~i~ades, NY 10964, USA.

86:3869 Edmond, J.M. and K.L. Von Damm, 1985. Chem-

istry of ridge crest hot springs. Bull. biol. Soc. Wash., 6:43-47.

On open ocean ridge axes, e.g. EPR, the reactants are seawater and basalt; solutions of relatively uniform composition result. They are acidic and generally enriched in the alkalis and alkaline earths but completely depleted in Mg and SO 4. On buried axes the sediment cover provides an additional reactant. In Guaymas Basin reaction with biogenic calcite and organic carbon results in high pH and alkalinities and very large concentrations of am- monia. Sulphide-forming elements are precipitated and very high H2S:Fe ratios result. In both situations the only chemical constituent essential to vent

OLR (I 986)33 (7) D. Submarine Geology and Geophysics 567

organisms supplied by the hot fluids is H2S; other nutrients are available from the ambient waters. Dept. of Earth, Atmos. and Planet. Sci., E34-201, MIT, Cambridge, MA 02139, USA.

86:3870 Kadko, David, Randolph Koski, Mitsunobu

Tatsumoto and Robin Bouse, 1985/86. An estimate of hydrothermal fluid residence times and vent chimney growth rates based on 2~°Pb/Pb ratios and mineralogic studies of sulfides dredged from the Juan de Fuca Ridge. Earth planet. Sci. Letts, 76(1-2):35-44.

The Pb isotope ratios of two sulfide samples suggest that the residence time for hydrothermal fluids (from the beginning of alteration) is shorter than the half-life of Pb-210 (22.3 yr). Apparent growth rates of the samples were consistent with mineralogic and textural observations. Coll. of Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA. (gsb)

86:3871 Kleinschmidt, Michael and Richard Tschauder,

1985. Shallow-water hydrothermal vent systems off the Palos Verdes Peninsula, Los Angeles County, California. Bull. biol. Soc. Wash., 6:485- 488.

Geologic mapping in the intertidal and shallow subtidal zone on the Palos Verdes Peninsula has established a correlation between hydrothermal vent fields supporting chemosynthetic bacteria, fold belts and calcite-filled fissures. The vent fields emit warm, fresh, H2S-rich water. Vents take in cold water during high tides at depths > 3 m and emit warm (28°C) water during lower tides. Source of the vent field water is unknown. P.O. Box 2334, Van Nuys, CA 91401, USA.

86:3872 Malahoff, Alexander, 1985. Hydrothennal vents and

polymetallic sulfides of the Galapagos and Gorda/Juan de Fuca ridge systems and of submarine volcanoes. Bull. biol. Soc. Wash., 6:19-41.

Submersible-generated geological data showed that extended ridge crest activity, particularly along rift valley boundary faults, could result in the formation of large-volume massive sulfide bodies on the contemporary ocean crust, and that the massive sulfide deposits of the Galapagos Ridge are similar in geology, size, and mineralogy to those found on subaerial fossil oceanic crust. The observations also suggest a wide variability in size of polymetallic sulfide deposits, an increase in vent activity in response to local tectonic deformation, and a lack of

commercially viable deposits (although they may be discovered in the future in the back-arc basins of the Pacific). Univ. of Hawaii, Dept. of Oeeanogr., Honolulu, HI 96822, USA. (gsb)

86:3873 Simoneit, B.R.T., 1985. Hydrothermal petroleum:

composition and utility as a biogenic carbon source. Bull. biol. Soc. Wash., 6:49-56.

Sedimentary organic matter is easily converted to petroleum by hydrothermal activity. In the Guaymas Basin this petroleum is mature and migrates upward in fluids to the seabed, where heavy fractions condense and are deposited with sulfides. Wherever these petroleums are accessible, as on mound surfaces or in unconsolidated sediments, they are rapidly altered by microbes, similar to alteration observed in some reservoir petroleums. Hydrother- mal petroleum fractions in the Guaymas Basin provide a major carbon source for vent microbiota. Coll. of Oceanogr., Oregon State Univ., Corvallis, OR 97331, USA.

D170. Historical geology, stratigraphy 86:3874

Aksu, A.E. and P.J. Mudie, 1985. Late Quaternary stratigraphy and paleoecology of northwest Lab- rador Sea. Mar. Micropaleont., 9(6):537-557.

Thin bedded distal turbidites are important con- stituents on the continental slope and rise. Sedi- mentation on the outer shelf is dominated by ice-rafting and hemipelagic deposition. Subarctic surface waters penetrated into the northern Lab- rador Sea during the early-middle glacial stages; northward advection of warm air masses occurred at the same time. Late glacial stages were characterized by year-round sea-ice cover and arctic surface water, and by the dominance of cold, dry Arctic air masses. Dept. of Earth Sci., Memorial Univ. of Newfound- land, St. John's, NF AIB 3X5, Canada.

86:3875 Badgley, Catherine, Lisa Tauxe and F.L. Bookstein,

1986. Estimating the error of age interpolation in sedimentary rocks. Nature, Lond., 319(6049): 139-141.

While the average sedimentation rate can be used to infer the time of occurrence of an event from its stratigraphical position, the inferred age has an uncertainty deriving from the variability in rate of sediment accumulation over all shorter timescales. Based on the magnetostratigraphy of Miocene

568 D. Submarine Geology and Geophysics OLR (I 986) 33 (7)

Siwalik sediments from Pakistan, for long periods (>10 ~ yr), sediment accumulation is approximately linear through time; over short intervals (1@-105 yr), however, there is considerable variability. To provide an error term for an absolute age interpolated between boundaries of polarity units, a resampling technique similar to the statistician's 'bootstrapping' is employed and illustrated. Mus. of Paleontol., Univ. of Michigan, Ann Arbor, MI 48109, USA.

86:3876 Bertrand, Jean, Peter Nievergelt and Marc Vuagnat,

1985. Paleo-oceanic interpretation of a pelagic sequence with detrital ophiolitic material: the Chabri~re Series, basal complex of the Mont- gen~vre ophiolitic Massif (western Alps). C. r. Acad. Sci., Paris, (S6r. II)301(16): 1199-1204. (In French, English abstract.) Dept. de Mineral., Univ. de Geneve, 13, rue des Maraichers, 1211 Geneva 4, Switzerland.

86:3877 Boardman, M.R. et al., 1986. Banktop responses to

Quaternary fluctuations in sea level recorded in periplatform sediments. Geology, geol. Soc. Am., 14(1):28-31.

Sea level fluctuations and banktop sedimentation patterns, rather than dissolution cycles or turbidity currents, are responsible for observed variations in carbonate mineralogy. Sea level highstands are recorded as abrupt increases in exported Sr-rich aragonite from banktop organisms on top of Sr-poor aragonite and calcite from plankton. Sedimentation pulses are correlated with higher water temperatures, decreased ice volume, and rising sea level. Although a warm climate and high sea level endured, the offbank sediment transport gradually decreased following tile abrupt changes. It is suggested that offbank transport is restricted as reefs, shoals and islands develop, tidal flats grow and lagoons fill in. Dept. of Geol., Miami Univ., Oxford, OH 45056, USA. (msg)

86:3878 Boyle, E.A. and L.D. Keigwin, 1985/86. Comparison

of Atlantic and Pacific paleochemical records for the last 215,000 years: changes in deep ocean circulation and chemical inventories. Earth planet. Sci. Letts, 76(1-2):135-150.

Benthic Foraminifera 6~3C and Cd/Ca data from North Atlantic and equatorial Pacific cores indicate nutrient-depleted Atlantic bottom waters relative to the Pacific over the past 215,000 years, suggesting a continuous but variable net flux of nutrient-depleted water from the western North Atlantic into the

Pacific. Glacial ocean water was estimated to have 22% more Cd and 0.46 ppt less ~3C than the modern ocean; a 41 Kyr periodicity in relative North Atlantic Deep Water formation, lagging high latitude insolation maxima by 8--+ 2 Kyr, was observed. Dept. of Earth, Atmos. and Planet. Sci., MIT, Cambridge, MA 02139, USA. (gsb)

86:3879 Crowley, T.J., D.A. Short, J.G. Mengel and G.R.

North, 1986. Role of seasonality in the evolution of climate during the last 100 million years. Science, 231(4738):579-584.

A simple climate model is used to calculate the effect of past changes in land-sea distribution on the seasonal cycle of temperatures during the last 100 m.y. Modeled summer temperatures decreased over Greenland by more than 10C ° and over Antarctica by 5 to 8C °. For the last 80 m.y. this thermal response is comparable in magnitude to estimated atmospheric carbon dioxide effects. Analysis of paleontological data provides some support for the hypothesis that large changes due to seasonality may have sometimes resulted in an ice-free state due to high summer temperatures rather than year-round warmth. Such 'cool' non-glacials may have prevailed for as much as one-third of the last 100 m.y. Climate Dynamics Prog., NSF, Washington, DC 20550, USA.

86:3880 Fegley, Bruce Jr., R.G. Prinn, Hyman Hartman and

G.H. Watkins, 1986. Chemical effects of large impacts on the Earth's primitive atmosphere. Nature, Lond., 319(6051):305-308.

The shock heating and rapid quenching caused by the impact of large bodies into the atmosphere could produce molecules such as HCN and H2CO which are important precursors for the abiotic synthesis of complex organic molecules. This process is modelled for a wide range of temperatures, pressures and initial compositions. For atmospheres with C/O >/1, results suggest that bolide impacts cause HCN volume mixing ratios of approximately 10 -3 to l(Y 5 in the impact region and global average ratios of 1(~ 5 to l ( r ~z. The corresponding H2CO ratios are 10 7 to 10~9; n o global mixing can occur, however, as H2CO is rapidly destroyed or rained out of the atmosphere within days to hours. Rainout to the oceans of 3-15% of the HCN produced can provide ~ ( 3 - 14) × 10 j~ mol HCN per year, somewhat larger than other predicted sources of HCN and H2CO on the primitive Earth. Dept. of Earth, Atmos., and Planet. Sci., MIT, Cambridge, MA 02139, USA.

OLR (1986) 33 17) D. Submarine Geology and Geophysics 569

86:3881 Gilbert, Robert, 1985. Quaternary glaciomarine

sedimentation interpreted from seismic surveys of fiords on Baffin Island, N.W.T. Arctic, 38(4): 271-280.

Five sedimentary facies can be recognized in the seismic records: a basal facies of ice contact glacial sediment; a lower glaciomarine facies of well- stratified sediment; a facies deposited in a lower energy environment farther from sources of glacial sediment; an upper, well-stratified facies interpreted as ice-proximal; and a thin facies of modern sediment on top. These facies are tentatively correlated with glacial events on eastern Baffin Island. Dept. of Geogr., Queen's Univ., Kingston, ON K7L 3N6, Canada.

86:3882 Glass, B.P., C.A. Burns, J.R. Crosbie and D.L.

DuBois, 1985. Late Eocene North American microtektites and elinopyroxene-bearing spherules. J. geophys. Res., 90(Suppl.):D175-D196.

Approximately 35 mya two events, separated by only 10,000-20,000 yr, spread roughly 1 billion metric tons of silicate spherules over large areas of the Earth. The older event produced mostly clinopy- roxene-bearing spherules. The layer is associated with an iridium anomaly, appears to coincide with the extinction of several species of Radiolaria, and is probably related to an impact event. The other, younger layer of spherules consists of microtektites belonging to the North American tektite strewn field. This layer is not synchronous with an iridium anomaly, and does not appear to be associated with major changes in microfossils. Neither the earlier spherule event nor the tektite event appears to be associated with a climatic change, but no detailed studies have been made across either layer. Geol. Dept., Univ. of Delaware, USA.

86:3883 Grieve, R.A.F,, V.L. Sharpton, A.K. Goodacre and

J.B. Garvin, 1985/86. A perspective on the evidence for periodic cometary impacts on Earth. Earth planet. Sci. Letts, 76(1-2): 1-9.

From the point of view of completeness of search and crater retention, the record used to argue for statistical periodicities is incomplete and may not be representative. Estimates of crater ages are of variable accuracy and precision; it is possible to define through time-series analysis a number of periodicities of different magnitude and phase, depending on which craters are considered the most representative sample of the record. Arguing against periodic cometary showers is the observation that

estimates of the average cratering rate in recent time and observations on Apollo bodies are equivalent. In addition, siderophile element data from impact melt rocks suggest a variety of projectile types were responsible for relatively large terrestrial craters. Earth Phys. Br., Dept. of Energy, Mines and Resources, Ottawa, ON KIA 0Y3, Canada.

86:3884 Haymon, R.M. and R.A. Koski, 1985. Evidence of an

ancient hydrothermai vent community: fossil worm tubes in Cretaceous sulfide deposits of the Samail ophiolite, Oman. Bull, biol. Soc. Wash., 6:57-65. Marine Sci. Inst., Univ. of California, Santa Barbara, CA 93106, USA.

86:3885 Jaffrezo, Michel, Fida Medina and Jean Chorowicz,

1985. Microbiostratigraphic data about Late Jurassic in the western Moroccan Basin: comparison with the result of Leg 79 DSDP and the Cyamaz survey 1982. Bull. Soc. g~ol. Ft., (8)I(6): 875-884. (In French, English abstract.)

Based on calpionellid, foraminiferan and dasyclad data, the west Moroccan Upper Jurassic stratigraphy is updated. The Mazagan Escarpment is very similar to outcrops south of E1 Jadida in the western High Atlas, supporting the idea of a West Moroccan Basin on the Atlantic margin. Medina: Inst. Sci., Univ. Mohammed V., Ave. Ibn Batouta, B.P. 703, Rabat, Morocco. (msg)

86:3886 Joyce, J.E., M.C. Kennicutt II and J.M. Brooks,

1985. Late Quaternary depositional history of the deep western Gulf of Mexico: geochemical and sedimentologic evidence. Mar. Geol., 69(1-2):55- 68.

Recent sediments differ from those deposited during the Y-zone (Late Wisconsin) by (1) higher CaCO 3 content; (2) increased grain size; (3) ~50% less organic carbon; (4) heavier 8~3C-organic carbon; and (5) lower C /N ratios indicating an apparent pref- erential loss of sedimentary N. During the Y-zone, sea level was lower, allowing a greater influx of fine, carbonate-poor sediments of terrestrial origin. De- creased surface productivity and increased CaCO 3 dissolution may also have contributed to the increase in carbonate-poor sediments. Union Oil of Cali- fornia, 900 Executive Plaza West, 4635 Southwest Freeway, Houston, TX 77027, USA.

86:3887 Kempe, Stephan and E.T. Degens, 1985. An early

soda ocean? Chem. Geol., 53(1-2):95-108.

570 D. Submarine Geology and Geophysics OLR (1986)33 (7)

It is postulated that the ancient sea had high alkalinity, high pH and low Ca and Mg concentrations. The change toward NaC1 dominance can best be explained by a series of mineral equilibria, crustal differentiation and life processes. In principle hydrothermal leaching of chlorine from the oceanic crust caused this ion to accumulate in the sea while at the same time dissolved carbonates became gradually removed by organisms and carbonates. The switch from a soda to a halite ocean was accomplished ~ l Ga ago. Geol.-Paleontol. Inst., Univ. of Hamburg, D-2000 Hamburg 13, FRG.

86:3888 Koepnick, R.B. et al., 1985. Construction of the

seawater 87Sr/~Sr curve for the Cenozoic and Cretaceous: supporting data. Chem. Geol., 58(1- 2):55-81.

Data used to construct the Cenozoic and Cretaceous portion of the Phanerozoic seawater gVSr/86Sr curve are presented. More than 98% of the data points fall within a narrow band, such that for any given time the correct ratio probably lies within this band. Although the general curve configuration is largely determined by plate interactions and seafloor spreading, the influences of a variety of factors on specific increases or decreases complicate straightforward plate tectonic interpretations. Mobil Res. and Develop. Corp., Dallas, TX 75234, USA. (gsb)

86:3889 Matsui, Takafumi and Yutaka Abe, 1986. Evolution

of an impact-induced atmosphere and magma ocean on the acereting Earth. Nature, Lond., 319(6051):303-305.

Early rapid formation of the atmosphere and hydrosphere on the terrestrial planets during accretion by planetesimal impacts is studied. These impacts increase the surface temperature and thus affect the formation of a proto-atmosphere or -hydrosphere by degassing of volatiles. An impact- induced H20 atmosphere increases the surface temperature of the Earth to a stage where a magma ocean is possible, with the total amount of H20 in the proto-atmosphere clustering around 10 :~ kg. The apparent coincidence of the H20 abundance in the proto-atmosphere with the present mass (~1.4 × 10 :~ kg) of the ocean is evidence for an impact origin for the atmosphere and hydrosphere. Geophys. Inst., Univ. of Tokyo, Bunkyo-ku, Tokyo 113, Japan.

86:3890 McLean, D.M., 1985. Mantle degassing unification of

the trans-K-T geobiological record. Evol. Biol., 19:287-313.

The author argues that the marine and terrestrial (dinosaurian) records from the Cretaceous-Tertiary support gradual faunal turnover over hundreds of thousands of years with marine extinctions pre- ceding terrestrial ones by 1.5 m.y. It is proposed that mantle degassing from extended Deccan Traps flood basalt volcanism (lasting 0.53-1.36 m.y.) perturbed the world's carbon balance by injecting 3.9-9.6 × 10 ~ moles CO 2 y r j into the atmosphere and ocean mixed-layer inducing dead-ocean conditions. Extended mantle release of iridium accounts for the iridium enrichment in marine records across the Cretaceous-Tertiary boundary. Dept. of Geol. Sci., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA 24061, USA. (msg)

86:3891 Nichols, D.J., D.M. Jarzen, C.J. Orth and P.Q.

Oliver, 1986. Palynologicai and iridium anomalies at Cretaceous-Tertiary Boundary, south-central Saskatchewan. Science, 231 (4739): 714-717.

The boundary is marked by coincident anomalies in abundance of iridium and fern spores at the extinction level of a suite of Cretaceous pollen taxa. Evidence of disruption of the terrestrial flora includes the fern-spore abundance anomaly and local extinction of as much as 30 percent of angiosperm species. The reorganized earliest Ter- tiary flora is made up largely of surviving species that assumed new roles of dominance. Persistence of climatically sensitive taxa across the boundary indicates that if paleoclimate was altered by the terminal Cretaceous event, it returned quickly to the pre-event condition. USGS, Denver, CO 80225, USA.

86:3892 Quilty, P.G., 1985. Miocene and PHocene sediments

dredged from the sea floor off St. Helens, northeastern Tasmania. Pap. Proc. R. Soc, Tasm., 119:93-101. Antarctic Div., Dept. of Sci., Kings- ton, Tasmania, Australia.

86:3893 Staudigel, Hubert, Pat Doyle and Alan Zindler,

1985/86. Sr and Nd isotope systematies in fish teeth. Earth planet. Sci. Letts, 76(1-2):45-56.

The high concentrations of Sr and Nd in fish teeth enable dating of red clays and analysis of inter- ocean chemical exchange using very small sample sizes. The samples appear to have derived their REE signature from seawater, rather than sediments during early diagenesis. The Atlantic and Pacific ocean Nd isotope signatures have been generally constant through the past 55 Ma and provide a more quantitative tool for exchange estimation than


faunal indicators. The limited data set also suggests that pre-Pliocene equatorial chemical exchange between the Atlantic and Pacific was less significant than the present day Antarctic Circumpolar Current. Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA. (gsb)

86:3894 Stoker, M.S. and Alistair Bent, 1985. Middle Pleis-

tocene glacial and glaciomarine sedimentation in the west central North Sea. Boreas, 14(4):325- 332. British Geol. Surv., Murchison House, West Mains Rd., Edinburgh EH9 3LA, Scotland.

86:3895 Vincent, l~dith, 1985. Carbonate stratigraphy of

Neogene and Quaternary deelv-sea sediments from the Pacific. Bull. Soc. gbol. Fr., (8)I(6):915- 924. (In French, English abstract.)

A comparison of Neogene and Quaternary carbonate stratigraphies from the temperate zone (Hess Rise) and the equatorial Pacific, allows a cross- latitudinal correlation of carbonate fluctuations. Specific carbonate events recognized throughout the equatorial Pacific are identified in the temperate area, showing the ocean-wide nature of these events. Dissolution spikes, recognizable in both areas, appear to be related to global changes in the chemistry of the ocean, linked to regression cooling events. Results do not imply, however that carbonate fluctuations were produced by only one or two master variables. At different times, the mix of processes responsible for the carbonate-fluctuation patterns may have varied considerably. Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA.

DIS0. Paleontology (see also E-BIOLOGICAL OCEANOGRAPHY)

86:3896 Barskov, I.S. et al., 1984. Palaeontology. Volume 2,

Proceedings of the 27th International Geological Congress, Moscow, 4-14 August 1984. VNU Science Press, Utrecht, The Netherlands; 222pp.

The 24 studies included here are relatively general in nature, dealing with such broad topics as evolution, reconstructive morphology, phylogeny, ecology and ecosystems, and biomineralization. Several authors deal with major plant and animal groups (angio- sperms, vertebrates, and fish-tetrapod relationships) and others analyze the ancient biota of particular time periods (the Vendian, Cambrian, Silurian, Jurassic and Early Cretaceous). Only two papers treat specific geographic areas, the East Baltic and

basins north of Siberia, and one describes research on molluscan nacre. (hbf)

86:3897 Bertels, Alwine, 1985. Neogene planktonic Forami-

nifera from the southern south-western Atlantic Ocean. Revta esp. Micropaleont., 17(2):221-252. (In Spanish, English abstract.) Dept. de Ciencias Geol., Univ. de Buenos Aires, Argentina.

86:3898 Boltovskoy, Esteban and Silvia Watanabe, 1985.

[Benthic Cenozoic Foraminifera from DSDP Site 305, NW Pacific.] Revta esp. Micropaleont., 17(2):281-314. (In Spanish, English abstract.) Museo Argentino de Ciencias Nat., Consejo Nac. de Invest. Cient. y Tecnicas, Argentina.

86:3899 Brummer, G.-J.A., Christoph Hemleben and Mi-

chael Spindler, 1986, Planktonic foraminiferal ontogeny and new perspectives for micropalaeon- tology. Nature, Lond., 319(6048):50-52.

By tracing the successive growth stages of extant representatives of this group, criteria have been obtained which identify pre-adult forms that, tra- ditionally, have been disregarded in foraminiferal research. Comparative studies of growth series at species and supraspecific levels allowed the iden- tification of three major species groups, each showing three different developmental stages. Their recognition introduces new possibilities for establishing a natural classification of planktonic fora- minifers, for disclosing their evolutionary history and for testing evolutionary models in general. Inst. of Earth Sci., Free Univ., P.O. Box 7161, 1007 MC Amsterdam, Netherlands.

86:3900 Fryer, Geoffrey et al., 1985. Fossil arthropods as

living animals. Trans. R. Soe. Edinb., 76(2- 3): 103-399; 24 papers.

The challenges of relating the fossilized remains of arthropods to their life modes and environments were explored at a 1984 symposium of the Royal Society of Edinburgh. Most of the papers presented there are included in this volume, which is divided into five sections. The first considers evidence from living forms--structure and habits of branchiopods, swimming behavior and sensory structures of Crus- tacea, and Chelicerata functional morphology. Sec- tion two concerns inferences from exceptionally preserved faunas--the Middle Cambrian Burgess Shale (British Columbia), the Upper Cambrian


Orsten (Sweden), Lower Carboniferous shrimp from Gullane (Scotland), and Lower Cretaceous lobster species (England). Section three deals with relationships between facies and paleogeography and morphology, and section four takes up structure and function. The final section investigates the 'imper- fectly understood', widely distributed, diverse Thyla- cocephala, Conchyliocarida and Concavicarida. (hbf)

86:3901 Johnson, D.A. and C.A. Nigrini, 1985. Synchronous

and time--transgressive Neogene radiolarian datum levels in the equatorial Indian and Pacific oceans. Mar. Micropaleont., 9(6):489-523.

Examination of 50 radiolarian events within a low latitude zone with minimal morphological variations of individual taxa, high assemblage diversity, and previously documented stratigraphic continuity, revealed distinctly time-transgressive (range of ages

1.0 m.y.), as well as synchronous datum levels. The pattern of taxa appearance was often opposite to that predicted by east-to-west zonal flow, and most synchronous events were last occurrences while most time-transgressive events were first appearances. Implications for determinations of global time scales are discussed. WHOI, Woods Hole, MA 02543, USA. (gsb)

86:3902 Knudsen, K.L., 1985. Foraminiferal stratigraphy of

Quaternary deposits in the Roar, Skjold and Dan fields, central North Sea. Boreas, 14(4):311-324. Dept. of Micropaleontol., Inst. of Geol., Univ. of Aarhus, DK 8000 Arhus C, Denmark.

86:3903 Mateu, G., 1985. [Calcareous nannoplankton from the

Pliocene and Quaternary in the Balearic Sea: chronostratigraphic and paleohiogeographic implications.] Revta esp. Micropaleont., 17(2): 167- 200. (In Spanish, English abstract.) Inst. Espanol de Oceanografia, Lab. Oceanografico de Baleares, Argentina.

86:3904 Sierro, F.J., 1985. The replacement of the "Globoro-

talia menardii' group by the Globorotalia miotu. m/da group: an aid to recognizing the Tortonian- Messinian boundary in the Mediterranean and adjacent Atlantic. Mar. Micropaleont., 9(6):525- 535. Dept. of Paleontol., Univ. of Salamanca, 37008 Salamanca, Spain.

D200. Gravity, geodesy, magnetism 86:3905

Bowin, Carl, Edward Scheer and Woollcott Smith, 1986. Depth estimates from ratios of gravity, geoid, and gravity gradient anomalies. Geophysics, 51(1):123-136.

Utilizing geoid, gravity and vertical gravity gradient data for depicting mass anomalies is compared with spatial and spectral depth estimation methods. New rules for the data are developed; both spatial and frequency-domain methods are discussed. Simple ratios of single observations of the data types provide information comparable to traditional ana- lyses of one data type alone. WHOI, Dept. of Geol. and Geophys., Woods Hole, MA 02543, USA. (slr)

86:3906 Van Wagoner, N.A., 1986. The structure and pale-

omagnetism of North Atlantic Ocean Layer 2: segregation vesicle determinations. J. Geol., 94(I):27-46.

If it is assumed that the orientation of residual melts are gravity controlled and remain fixed during segregation, solidification, and magnetization, the segregation vesicle technique offers a means for determining the horizontal position of certain seafloor basalts. The first results of the application of this technique to basaltic basement rocks indicates that at DSDP sites 334, 395, 395A, and 396B samples exhibited upright dips of 4 ° to 41 ° but at sites 332A and B, samples ranged from 20 ° upright to 14 ° overturned, suggesting that they had been internally deformed or were part of a megabreccia formed by mass wasting of uplifted fault blocks. The results point to the need for making thickness corrections on dipping strata and suggest that marine magnetic lineation either may not always represent the Earth's magnetic field at the time of formation or may indicate a deeper magnetic source layer in the North Atlantic. Dept. of Geol., Acadia Univ., Wolfville, NS BOP IX0, Canada. (hbf)

86:3907 von Frese, R.R.B., W.J. Hinze, R. Olivier and C.R.

Bentley, 1986. Regional magnetic anomaly constraints on continental breakup. Geology, geoL Soc. Am., 14(1):68-71.

Magsat satellite maps of magnetic anomalies of North and South America, Euro--Africa, India, Australia, and Antarctica were corrected for variable elevation and changes in the geomagnetic field by equivalent point-source inversion. The resultant continental scale anomaly patterns, plotted on a reconstruction of Pangaea, exhibit 'remarkable


correlation of regional lithospheric magnetic sources across rifted margins.' Dept. of Geol. and Mineral., Ohio State Univ., Columbus, OH 43210, USA. (msg)

D210. Heat flow

86:3908 Beck, A.E., K. Wang and P.Y. Shen, 1985. Sub-

bottom temperature perturbations due to tem- peratare variations at the boundary of inhomo- geneous lake or oceanic sediments. Tectono- physics, 121(1):l 1-24.

For reliable heat flow measurements made in the top few meters of sediments at the bottom of lakes, an accurate record of the temperature history for several years at the top of the sediment should be available and if the thermal properties are not constant with depth, then the depth-dependence should be known. Errors that may arise if either or both of these conditions cannot be met can be serious; there are occasions where a temperature- depth plot which is linear within normally accept- able limits of accuracy and with a gradient that is within the range of expectations may be as much as 100% in error. Dept. of Geophys., Univ. of Western Ontario, London Ont. N6A 5B7, Canada.

D240. Local or regional tectonics

86:3909 Brozena, J.M., 1986. Temporal and spatial variability

of seafloor spreading processes in the northern South Atlantic. J. geophys. Res., 91(B1):497-510.

Aeromagnetic data covering a 700,000 km 2 area of the Mid-Atlantic Ridge south of Ascension Island provide a detailed picture of the tectonic framework and spreading history of a slow-spreading ridge. The data reveal a marked increase in spreading rate at 10 Ma and a decrease between 6 Ma and the present, similar to variations noted in the North Atlantic and eastern Pacific. Shifts in plate motion resulting from fragmentation and rotation correlate with periods of changing spreading rate. The data also demonstrate the effect of the Ascension hotspot on the ridge and the presence of two apparent seamount chains formed by the hotspot. Acoustics Div., Naval Res. Lab., Washington, DC, USA, (hbf)

86:3910 Cande, S.C. and R.B. Leslie, 1986. Late Cenozoic

tectonics of the southern Chile Trench. J. geophys. Res., 91(B1):471-496.

Marine geophysical data from offshore southern Chile, where a collision between an active spreading ridge and trench are occurring, indicate that three collision events have taken place during the past 15 m.y. A 700-kin-long section of the ridge was subducted between 14 and 10 Ma, and shorter sections offset by transform faults were subducted between 6 and 3 Ma. More recently, subduction of the landward trench slope has occurred in the area of the triple junction. It is concluded that the configuration of spreading centers and transform faults on the Chile Rise has been the chief controlling factor for ridge/trench tectonic interactions. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA. (hbf)

86:3911 Green, A.G. et al., 1986. Seismic reflection imaging

of the subducting Juan de Fuca Plate. Nature, Lond., 319(6050):210-213.

McKenzie and Parker's early suggestion that the Juan de Fuca plate is underthrusting North America has since been confirmed by numerous studies. The results of a seismic reflection survey have delineated two slabs of oceanic lithosphere underlying Van- couver Island, one that is currently being subducted and one that is underplated. These findings suggest that successive underplating of oceanic lithosphere may be an important process in the evolution and growth of continents. Div. of Seismol. and Geo- magnetism, 1 Observatory Crescent, Ottawa, ON K1A 0Y3, Canada.

86:3912 Mitchell, C., G.K. Taylor, K.G. Cox and J. Shaw,

1986. Are the Falkland Islands a rotated microplate? Nature, Lond., 319(6049): 131-134.

Palaeomagnetic evidence from dolerite dykes on West Falkland suggests that the Falkland Islands were rotated through ~ 120 ° during the early stages of the break-up and dispersal of the southern part of Gondwanaland, supporting the proposal (Adie, 1952) that the islands were formerly situated adjacent to South Africa, where they formed the south-east corner of the Karoo basin. The first stage of continental drift probably took place during the Jurassic, as Antarctica separated from southern Africa, the islands moving as a microplate to a position ~500 km southeast of present-day Cape Town. Subsequently, the islands and plateau have drifted to their present position and undergone a further rotation of ~ 6 0 °. Dept. of Earth Sci., Univ. of Oxford, Parks Rd., Oxford OX1 3PR, UK.


86:3913 Stein, Seth, D.A. Wiens, J.F. Engeln, Kazuya Fujita

(comment), W.R. McCann and L.R. Sykes (reply), 1986. Comment on 'Subduction of aseismie ridges beneath the Caribbean Plate: implications for the tectonics and seismic potential of the northeastern Caribbean' by W.R. McCann and L.R. Sykes. J. geophys. Res., 91(B 1):784-786.

The conclusion that major seismic gaps where large interplate thrust earthquakes may occur exist in the northern Lesser Antilles subduction zone is ques- tioned by Stein et al. who state that intraplate normal faulting, not interplate thrust faulting, dominates recent seismic events, and that historically plate motion has been mainly aseismic. McCann and Sykes' reply details the differences between seis- micity in the Lesser Antilles and the Bonin-Mariana zone. Dept. of Geol. Sci., Northwestern Univ., Evanston, IL, USA. (msg)

D250. Plate and global tectonics

86:3914 Bryan, Phillip and R.G. Gordon, 1986. Errors in

minimum plate velocity determined from paleomagnetic data. J. geophys. Res., 91(B1):462-470.

Previous studies based on paleomagnetic data, which indicate that minimum velocities of ancient continents exceed present-day velocities of major continents, have failed to take into account known errors in paleomagnetic data. A new technique, which combines Gordon et al.'s (1979) method for determining minimum velocities with a Monte Carlo simulation is applied to Pennsylvanian to Cretaceous data for North America and Laurasia. Although the recalculated velocities are 10 to 50 km/m.y, lower, they are still much higher than present-day velocities and support the conclusion that the relatively slow motion of today's major continents is not a fun- damental characteristic of large continental masses. Dept. of Geol. Sci., Northwestern Univ., Evanston, IL, USA. (hbf)

86:3915 Engebretson, D.C., Allan Cox and R.G. Gordon,

1985. Relative motions between oceanic and continental plates in the Pacific Basin. Spec. Pap. geol. Soc. Am., 206:59pp.

A qualitative plate tectonic model is developed to describe the relative motions of western North

America, eastern Eurasia, and adjacent oceanic plates over the past 180 m.y. The model is based on the assumption that hotspots in the Atlantic and Pacific have remained fixed relative to each other over this interval; results are expressed in tables of Euler Poles; reconstructions portray the former locations of the North America, Farallon, Kula, and Izanagi plates at 20, 37, 56, 65, 80, 110, and 140 Ma. The analysis suggests that the Kula and Izanagi plates moved south-to-north through the Pacific to be rapidly subducted beneath Eurasia and obliquely beneath North America; whereas the Farallon Plate moved west-to-east and was rapidly subducted beneath North America. Both the ages and bathymetry of the subducted plates are shown to vary markedly along the strike of the trenches. Dept. of Geol., Western Washington Univ., Bellingham, WA 98225, USA. (hbf)

86:3916 Molnar, Peter and J.M. Stock, 1985. A method for

bounding uncertainties in combined plate reconstructions. J. geophys. Res., 90(B14):12,537- 12,544.

Based on previous observations of Stock and Molnar (1983), a method for calculating uncertainties in plate reconstruction is presented which utilizes the reconstructed position of specific points on individual plates rather than on pole positions and rotation angles. An analysis of the relationship of the Pacific Plate with respect to North America at Anomaly 6 (20 Ma) illustrates the method. Dept. of Earth, Atmos. and Planet. Sci., MIT, Cambridge, MA 02139, USA. 0abf)

86:3917 Scholl, D.W., T.L. Vallier and A.J. Stevenson, 1986.

Terrane accretion, production, and continental growth: a perspective based on the origin and tectonic fate of the Aleutian-Bering Sea region. Geology, geol. Soc. Am., 14(1):43-47.

The Aleutian-Bering Sea region is presented as an example of 'a tectonic setting capable of producing continental crust fabricated largely of kindred rather than exotic terranes.' Evidence is cited which indicates that the region represents a single exotic fragment of oceanic crust that was sutured to the Alaskan-Siberian margin about 55 Ma. It is hy- pothesized that the orogenesis of the region would produce a new area of Pacific-rim mountain belts, and that other examples of kindred assemblages of terranes should-exist in other ocean-rim mountain belts. USGS, Menlo Park, CA 94025, USA. 0abf)


D280. Volcanism, magmatism

86:3918 Cann, J.g., M.R. Strens and A. Rice, 1985/86. A

simple magma-driven thermal balance model for the formation of volcanogenic massive suiphides. Earth planet. Sci. Letts, 76(1-2): 123-134.

A model of black smoker hydrothermal circulation based on mid-ocean ridge observations examines the 'balance of heat, water flow, and temperature in a long-lived single-pass system heated by magnetic heat.' The results indicate that generation of a 3-million ton sulfide deposit with 70% efficiency at 350°C water temperature within 4000 yr requires a heat flux of 110 W m 2 from a magma chamber with a plan area of 2 km 2 for a mass flow rate of 140 kg/s ~. At temperatures of 250°C the required heat flux drops to 60W m 2, but the required time becomes 33,000 yr and overall heat requirements quadruple. Dept. of Geol., Univ. of Newcastle upon Tyne, NE1 7RU, UK. (hbf)

86:3919 Daly, S.F. and Arthur Raefsky, 1985. On the

penetration of a hot diaplr through a strongly temperature-dependent viscosity medium. Geophys. Jl R. astr. Soc., 83(3):657-681. Dept. of Earth, Atmos. and Planet. Sci., MIT, Cam- bridge, MA 02139, USA.

86:3920 Olmez, I., D.L. Finnegan and W.H. Zoller, 1986.

Iridium emissions from Kilauea Volcano. J. geophys. Res., 91(B1):653-663.

Gas and particulates from two of three sampled cooling vents were highly enriched (10 S fold) in Ir, presumably related to the deep source of the magma. An emission rate of ~3 g Ir/l@ m 3 of magma is estimated from these and other data. Results suggest that the Ir anomaly found at the Cretaceous- Tertiary boundary might have been the result of deep source volcanism. Nuclear Reactor Lab., MIT, Cambridge, MA 02139, USA. (gsb)

86:3921 Quinby-Hunt, M.S~, P. Wilde, D. Corrigan, A.T.

Dengler and W.R. Normark, 1986. Very recent analogs of volcanogenic Arehean sequences. Geology, geol. Soc. Am., 14(1):48-51.

Coatings on tholeiitic glassy basalt samples from the active submarine volcano, Loihi Seamount, were analyzed to compare very recent oceanic crust with that formed in the early ocean. The <0.062-mm fraction was amorphous iron hydroxide containing low amounts of REE; the >0.062-mm fraction was

sand-sized grit composed of olivine, opaque magnetic material and basaltic glass. The absence of palagonite or smectite and of an gEE signature suggests minimal interaction with seawater; thus the samples provide an unmetamorphosed analog of ancient rocks, and suggest an additional iron source for the Early Archean. Dept. of Paleontol., Univ. of Calif., Berkeley, CA 94720, USA. (msg)

86:3922 Zhuravlev, D.Z., A.Z. Zhuravlev and I.V. Cherny-

shev, 1985. Isotopic zoning in the Karile Island arc indicated by t43Nd/144Nd and STSr/S6Sr ratios. Int. Geol. Rev., 27(7):781-785.

Determination of neodymium and strontium isotopes in lava samples from the rear and frontal zones of the Kurile Island Arc (KIA) in conjunction with petrochemical and geochemical data revealed a previously unknown transverse isotopic zoning pattern. Since crustal material apparently contrib- utes little to the Nd and Sr compositions of KIA Quaternary volcanics, these values should be similar to those for the upper mantle below the arcs, suggesting compositional heterogeneity in the magma source. IGEM, Acad. of Sci., Moscow, USSR. (gsb)

D290. Crust, mantle, core

86:3923 Bonatti, Enrico, Giulio OttoneUo and P.R. Hamlyn,

1986. Peridotites from the Island of Zabargad (St. John), Red Sea: petrology and geochemistry. J. geophys. Res., 91(B1):599-631.

The geochemistry and petrology of exceptionally fresh peridotite samples collected on Zabargad, which lies 50 km west of the Red Sea axis within a young rift in a transition zone between oceanic and continental lithosphere, suggest that these rocks provide 'a sample of oceanic mantle before extrac- tion of the basaltic oceanic crust,' and were emplaced into the crust during the post-Mesozoic development of the Red Sea rift. The peridotites are of 3 types: protogranular spinel lherzolite, probably representing undepleted parental mantle material; amphibole peridotite, probably formed in contact with H20-rich metasomatic fluids; and plagioclase peridotites thought to include a melt component which was incorporated as the lherzolite ascended. Lamont-Doherty Geol. Observ., Palisades, NY 10964, USA. 0abf)

86:3924 Boudier, F. and A. Nicolas, 1985/86. Harzimrgite

and lherzoHte subtypes in ophiolltic and oceanic


environments. Earth planet. Sci. Letts, 76(1- 2):84-92.

In most ophiolites the ultramafic section is harz- burgitic, except for the local occurrence of impreg- nation lherzolites. Several characters validate the distinction between a harzburgite and a lherzolite ophiolitic subtype. The former can be derived from any oceanic spreading center, provided the rate ~ 1 cm/yr; the latter would correspond to situations (vicinity of transform fault, very slow spreading rates) where the lithospheric front penetrates at 20-30 km into the mantle below the spreading center. Lherzolitic massifs are best explained as being derived from slow-spreading rifts. Lab. de Tectonphys., 2 rue Houssiniere, 44072 Nantes, France.

86:3925 Boul~gue, Jacques, Xavier Le Pichon and J.T.

liyama, 1985. Earthquake prediction in Tokai area (Japan). C. r. Acad, Sci., Paris, (Str. II)301(16):1217-1219. (In French, English abstract.) Lab. de Geochim. et Metal., CNRS-UA no. 196, 4 place Jussieu, 75230 Paris Cedex 05, France.

86:3926 Chiu, Jer-Ming, B.L. lsacks and R.K. Cardwell,

1985. Propagation of high-frequency seismic waves inside the subducted lithosphere from intermediate--depth earthquakes recorded in the Vanuatu Arc. J. geophys. Res., 90(B14):12,741- 12,754.

Three seismic phases associated with the slab of subducted lithosphere are interpreted as (1) a P wave refracting into the inner portion of the slab, (2) a P wave traveling mainly through the outer(upper) portion of the slab, and (3) a P to S converted wave in which the conversion occurs across the upper surface of the slab. Evidence suggests that these earthquakes are not located in the strong and cold inner core of the slab but within an outer zone where the velocity is lower. Large spatial variations in the transmission of high-frequency shear waves indicate that there is a localized zone of anomalous shear wave attenuation in the mantle wedge lying just above the subducted slab and beneath the active volcanoes. Tennessee Earthquake Information Cen- ter, Memphis State Univ., Memphis, TN, USA.

86:3927 Coleman, R.G., 1984. Preaccretion tectonics and

metamorphism of ophiolites. Ofioliti, 9(3):205- 222.

Tethyan (Iapetus) ophiolites form in small ocean basins and are emplaced across passive continental

margins consisting of marine sediments overlying Hercynian or Precambrian continental crust. Cir- cure-Pacific (Cordilleran) ophiolites are related to terrane accretion of interarc assemblages and most often are the basement rock of these terranes. Tethyan ophiolites often have narrow detachment metamorphic aureoles at their base produced during closing of small ocean basins over still active spreading centers; in contrast, the Cordilleran ophiolites rarely show basal detachment metamorphic aureoles. Most of the abyssal oceanic crust formed in the large ocean basins is totally consumed by subduction and the small fragments of ophiolite that we see in orogenic zones represents oceanic crust formed in small ocean basins of interarc settings. Therefore, preaccretion tectonics and metamorphism observed in ophiolites may not be representative of processes now observed within the oceanic crust of the major ocean basins. Geol. Dept., Stanford Univ., California, USA.

86:3928 Cserepes, L. and M. Rabinowicz, 1985/86. Gravity

and convection in a two-layer mantle. Earth planet. Sci. Letts, 76(1-2):193-207.

The models have two constant viscosity layers heated from below. The main variable is the viscosity ratio; other free parameters are the layer depths and the over-all Rayleigh number. As the viscosity of the lower layer is increased with respect to that of the upper layer, the flow structure shifts gradually from the dominance of viscous coupling of the layers toward thermal couplint,. Viscous coupling prevails when the viscosity ratio is near one, and produces pairs of cells which turn oppositely in the two layers. Thermal coupling predominates if the viscosity ratio is several hundred or more. In a series of models with a depth ratio 1:2, thermal coupling leads to pairs of cells which turn in the same sense in the two layers. Two-layer models of this type of convection are able to explain not only the sign of admittance but also the magnitude of observed gravity anomalies. Geophys. Dept., Eotvos Univ., Kun Bela ter 2, 1083 Budapest, Hungary.

86:3929 Dablain, M.A. and A.F. Linville, 1985. Case study in

seismic diffraction near a gulf coast salt dome. Oil Gas J., 83(41):137-141. Mobil Res. & Develop. Corp., Dallas, TX, USA.

86:3930 Davies, G.F., 1986. Mantle convection under simu-

lated plates: effects of heating modes and ridge and trench migration, and implications for the core-mantle boundary, bathymetry, the geoid and

OLR (1986) 33 (7) D. Submarine Geology and Geophysics 5"P'/

Benioff zones. Geophys. Jl R. astr. Soc., 84(1): 153-183.

A series o1 numerical convection models in which 'the lithosphere is simulated by imposing a piece- wise constant horizontal velocity boundary condition at the top of the convecting fluid' is presented and combinations of internal or bottom heating and prescribed bottom temperatures or heat flux are compared. It is shown that for the case with internal heating and an isothermal base, the thermal boundary layer at the base of the mantle may be reversed. Scaled to the whole mantle, calculated topographic, gravity, and geoid variations compare well with those observed at the Earth's surface. In addition, it is demonstrated that for models of ridge and trench migration there is considerable lag between surface plate configurations and underlying flow structure, and that horizontal shear associated with trench migration may affect the dip of the descending flow. Res. Sch. of Earth Sci., Australian Natl. Univ., Canberra, ACT 2600, Australia. (hbf)

86:3931 Engeln, J.F., D.A. Wiens and Seth Stein, 1986.

Mechanisms and depths of Atlantic transform earthquakes. J. geophys. Res., 91(BI):548-577.

A study of teleseismic mechanisms and depths of 40 earthquakes on major transforms along the Mid- Atlantic Ridge indicates that, except near ridge- transform intersections, strike-slip motion occurs along transform-parallel near-vertical planes. Trans- form earthquake centroid depths lie above the 400°C isotherm, whereas oceanic intraplate centroids ex- tend to the 750°C isotherm. With the exception of the deep faults of the Vema transform, slip rates appear to be consistent with those predicted from plate motions. It is suggested that the relatively shallow centroid depths of the transform 'may imply that transforms are either much weaker or much hotter than currently thought.' Dept. of Geol., Univ. of Missouri, Columbia, MO, USA. (hbf)

86:3932 Houseman, Gregory and Philip England, 1986. A

dynamical model of lithosphere extension and sedimentary basin formation. J. geophys. Res., 91(B1):719-729.

The possibility that upper mantle convection may produce normal stresses on the base of the continental lithosphere, which in turn produce localized uplifts of several hundred meters and extensional deviatoric stresses of several hundred bars, is investigated for stated conditions of biaxial strain, brittle failure, power law creep, and brittle power law for three different regimes representing high, low,

and intermediate stress levels. Res. Sch. of Earth Sci., Australian Natl. Univ., Canberra, Australia. (hbf)

86:3933 Huang, P.Y., S.C. Solomon, E.A. Bergman and J.L.

Nabelek, 1986. Focal depths and mechanisms of Mid-Atlantic Ridge earthquakes from body wave- form inversion. J. geophys. Res., 91(B1):579-598.

Fourteen earthquakes on the northern Mid-Atlantic Ridge (0°-72°N) are all characterized by nearly pure normal faulting on fault planes that dip at about 45 ° and strike parallel to the local trend of the ridge axis. Moments range from 3 to 15 x l024 dyn cm, and the source time functions are all of simple form. These earthquakes are all very shallow; centroid depths range between 1.2 and 3.1 km beneath the seafloor. The P waves show strong water column reverber- ations, suggesting that fault rupture extended to the seafloor. The centroid depths do not show a correlation with either spreading rate or seismic moment. Dept. of Earth, Atmos. and Planet. Sci., MIT, Cambridge, MA, USA.

86:3934 Jarvis, G.T. and W.R. Peltier, 1986. Lateral heter-

ogeneity in the convecting mantle. J. geophys. Res., 91(B1):435-451. Dept. of Earth and Atmos. Sci., York Univ., Downsview, Ontario, Canada.

86:3935 Karato, S., 1986. Does partial melting reduce the

creep strength of the upper mantle? Nature, Lond., 319(6051): 309-310.

The seismic low-velocity zone has been thought to correspond to a zone of partial melting that significantly reduces the creep strength, making it possible for plates to decouple from the underlying mantle. This view is examined in light of recent experimental results which show that water has more effect on the creep strength of olivine than does partial melting and that the former depends on the fugacity of water. When there is a limited amount of water, partial melting will result in depletion of water from olivine, and therefore have a hardening, rather than a softening, effect. Ocean Res. Inst., Univ. of Tokyo, Minamidai, Nakano, Tokyo 164, Japan.

86:3936 Karson, J.A. and H.J.B. Dick, 1984. Deformed and

metamorphosed oceanic crust on the Mid-Atlantic Ridge. Ofioliti, 9(3):279-302.

A detailed study of the area at 24°N at the plate corner where the Mid-Atlantic Ridge and Kane Fracture Zone intersect, was made with a camera


sled and the submersible Alvin. Observations indicate the presence of ridge-parallel faults and fissures and the effects of backtilting, mass wasting, and erosion. Samples collected between the fault zones included veined gabbros and minor diabases; within the fault and shear zones samples consisted of cataclasites, mylonites, and amphibolites; low-temperature vein fillings were found in fractures cutting deformation fabrics. The study reveals the extremely complicated nature of the oceanic fracture zone and suggests that the crust described here is 'part of a spectrum of crustal types produced at slow-spreading ridges that vary in crustal thickness, petrologic relations, and structural style.' Dept. of Geol. and Geophys., WHOI, Woods Hole, MA 02543, USA. (hbf)

86:3937 Knittle, Elise, Raymond Jeanloz and G.L. Smith,

1986. Thermal expansion of silicate perovskite and stratification of the Earth's mantle. Nature, Lond., 319(6050):214-216.

A pressure of 24 GPa and temperatures of about 2000--3000 K correspond to the observed 670-km seismic discontinuity which separates the upper and lower mantle. In such conditions the major minerals of the Earth's upper mantle transform to a distorted (orthorhombic) perovskite-structured mineral or to a perovskite-dominated assemblage. Despite its im- portance, little is known about its physical properties because of the difficulty in achieving the pressure and temperature required for synthesis. We have recently produced sufficient amounts of perovskite to measure its zero-pressure thermal expansion to 840 K by X-ray diffraction. At high temperatures, the large value for the thermal expansion coefficient implies that standard models of upper mantle composition, such as pyrolite or garnet peridotite, yield zero-pressure densities that are about 2% lower than that of the density of the lower mantle extrapolated to zero-pressure conditions. This result suggests that the upper and lower mantle are chemically distinct, in accord with layered models of the thermal and convective state of the mantle. Dept. of Geol. and Geophys., Univ. of California, Berke- ley, CA 94720, USA.

86:3939 Mitrovica, J.X. and G.T. Jarvis, 1985. Surface

deflections due to transient subduction in a convecting mantle. Tectonophysics, 120(3-4):211- 237.

A sequence of idealized numerical models of time-dependent mantle convection is developed to examine the magnitude and duration of transient surface deflections associated with non-continuous subduction. Flow velocities are determined for each instant from the evolving thermal field and are dynamically self-consistent. The results indicate that as the lithospheric slab sinks into the mantle, a broad topographic depression develops, and that topographic rebound, as slab-surface distance increases, varies with the temperature difference between slab and mantle. It is suggested that repeated intervals of subduction at continental margins may be a causal factor for cyclic platform sedimentation. Dept. of Phys., Univ. of Toronto, ON M5S 1A7, Canada. (hbf)

86:3940 Montagner, J.-P. and H.-C. Nataf, 1986. A simple

method for inverting the azimuthal anisotropy of surface waves. J. geophys. Res., 91(B1):511-520. Lab. de sismol., Inst. de Phys. du Globe, Univ. P. et M. Curie, 4 pl. Jussieu, 75230 Paris Cedex 05, France.

86:3941 Palmer, M.R. and K.K. Turekian, 1986. ~aTOs/~Os

in marine manganese nodules and the constraints on the crustal geochemistries of rhenium and osmium. Nature, Lond., 319(6050):216-220.

During their formation, ferromanganese nodules include and commonly concentrate dements dissolved in seawater. From measurements of 187Os/18608 ratios and comparison with the 143Nd/144Nd ratios of the same nodules, the Os isotopic composition and the osmium and rhenium concentrations of the weatherable portion of the continental crust, together with the proportions of 'ultramafic' and 'granitic' rock that constitute this crustal mass, have been calculated. Dept. of Earth, Atmos. and Planet. Sci., MIT, Cambridge, MA 02139, USA.

86:3938 Lrveque, J.-J. and Michel Cara, 1985. Inversion of

multimode surface wave data: evidence for sub-- i i ~ p h e r i c ani~atropy. Geophys. Jl R. astr. Soc, 83(3):753-773. Inst. de Phys. du Globe de Strasbourg, 5 rue rene Descartes, F-67084 Strasbourg cedex, France.

86:3942 Rowley, D.B. and Dork Sahagian, 1986. Depth-

dependent stretching: a different approach. Ge- ology, geol. Soc. Am., 14(1):32-35.

The cross-sectional geometries of several discon- tinuous, nonuniform or depth-dependent models, proposed to account for lithospheric stretching and


the uplift of rift shoulders accompanying it, are examined. A modification is proposed which in- volves 'continuous nonuniform stretching within a polygonal region bounded by symmetrical, out- ward-sloping boundaries within the mantle,' which could account for synrift uplift and doming without creating 'space problems' within the mantle. Dept. of Geophys. Sci., Univ. of Chicago, Chicago, IL 60637, USA. (hbf)

86:3943 Savage, J.C., M. Lisowski and W.H. Prescott, 1986.

Strain accumulation in the Shumagin and Yaka- taga seismic gaps, Alaska. Science, 231(4738): 585-587. USGS, Menlo Park, CA 94025, USA.

86:3944 Sereno, Thomas and John Orcutt, 1985. Synthesis of

realistic oceanic Po wave trains. J. geophys. Res., 90(B14):12,755-12,776. Inst. of Geophys. and Planet. Phys., Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA.

D330. Oil and gas

86:3945 Baird, R.A., 1986. Maturation and source rock

evaluation of Kimmeridge Clay, Norwegian North Sea. Am. Ass. Petrol. Geol. Bull., 70(1):1-11. Orogenic Studies Lab., Virginia Polytech. Inst., Blacksburg, VA 24061, USA.

86:3946 Coiling, E.L., B.H. Burda and P.A. Kelley, 1986.

Multidimensional pyrolysis-gas chromatography: applications in petroleum geochemistry. J. chromatog. Sci., 24(1):7-12. Texaco USA, Hous- ton Res. Center, Houston, TX 77042, USA.

86:3947 Ivanov, V.L., 1985. The geological prerequisites for

petroleum prediction in Antarctica. Int. Geol. Rev., 27(7):757-769.

The geology of Antarctic basins is reviewed in light of their potential petroleum content. Three sites-- the WeddeU Sea, Ross Sea, and Prydz Bay--are considered likely candidates for exploration. All- Union Res. Inst. of Ocean Geol., USSR. (msg)

D340. Manganese nodules, etc.

86:3948 Golden, D.C., C.C. Chen and J.B. Dixon, 1986.

Synthesis of todorukite. Science, 231(4739):717-

719. Dept. of Soil and Crop Sci., Texas A&M Univ., College Station, TX 77843, USA.

86:3949 Hein, J.R., F.T. Manheim, W.C. Schwab and A.S.

Davis, 1985. Ferrumanganese crusts from Necker Ridge, Horizon Guyot and S.P. Lee Guyot: geological considerations. Mar. Geol., 69(1-2): 25-54.

New information on three of the largest seamount- ridge features in the central Pacific reveals the presence of altered volcanic breccia cemented by phosphorite, together with mudstone, volcaniclastic sandstone, chert, basalt, and soft sediments. The vernadite, quartz and feldspar, and phosphorite, which compose the crusts, are tied, respectively, to hydrogenous precipitation, eolian input, and biogenic contributions. It is further shown that quartz and feldspar components decrease and phosphorite increases with decreasing latitude, perhaps reflecting zonal-wind patterns and equatorial upwelling. USGS, 345 Middlefield Rd., Menlo Park, CA 94025, USA. (hbf)

D360. Books, collections (general) 86:3950

Peive, A.V. et al., 1984. Tectonics. Volume 7, Proceedings of the 27th International Geological Congress, Moscow, 4-14 August 1984. VNU Science Press, Utrecht, The Netherlands; 383pp.

The influence of plate tectonic theory is evident throughout this 19-study volume. Among the general topics are crustal structure, orogenic divisions, active margins, continent/ocean transition zones, continental and geosynclinal foldbelts, rifting, and rock deformation. Although many of the presentations are global in scope, specific geographic areas investigated include: Siberia, the Middle America Trench off Guatemala, the Carpathian-Pannonian region, the Baikal rift and the periPacific. (hbf)

86:3951 Piccardo, G.B. and V. Bortolotti (eds.), 1984.

Ophiolites: oceanic tectonics and metamorphism. Special issue. Ofiofiti, 9(3):197-736; 23 papers plus abstracts.

The 23 papers included in this publication were among the 50 oral reports presented at the 2nd Annual Meeting of the Italian Working Group on Mediterranean Ophiolites, which was concerned primarily with the pre-orogenic structural and metamorphic evolution of ophiolites; other topics included the nature of ophiolite magmas and late orogenic tectonic-metamorphic evolution. The meeting began with general papers from invited speakers

580 OLR (1986) 33 (7)

describing the oceanic evolution of ophiolites, upper mantle kinematics in oceanic environments, and oceanic accretion-zone tectonics. Most of the reports centered upon ancient ophiolite sequences; only 2 were specifically concerned with present-day oceanic settings. (hbf)

D370. Miscellaneous 86:3952

Carton, J.A. and J.M. Wahr, 1986. Modelling the pole tide and its effect on the Earth's rotation. Geophys. Jl R. astr. Soc., 84(1):121-137.

The pole tide is the response of the ocean to incremental centrifugal forces associated with the Chandler wobble. Here, analytical models consider the tide first in a global ocean and then in an enclosed basin on a beta-plane; results approach equilibrium linearly with decreasing frequency and inversely with increasing basin depth. The numerical models solve Laplace's tidal equations over the World Ocean using realistic continental boundaries and bottom topography; results indicate that effects of the non-equilibrium portion of the deep ocean tide on the Chandler wobble period and damping are negligible. Center for Earth and Planet. Phys., Harvard Univ., Cambridge, MA 02138, USA.

E. BIOLOGICAL OCEANOGRAPHY

El0. Apparatus and methods 86:3953

Bossard, Peter and D.M. Karl, 1986. The direct measurement of ATP and adenine nucleotide pool turnover in microorganisms: a new method for environmental assessment of metabolism, energy flux and phosphorus dynamics. J. Plankt. Res., 8(1):1-13.

A method which enables the direct measurement of ATP and adenine nucleotide pool turnover is based upon the incorporation of 32po 4 into the a, fl, ~,-P positions of ATP. The method enables the calcu- lation of (1) the pool size of total biologically available P in water samples; (2) the rate of biochemical energy flux; and (3) the mean microbial community specific growth rate. Relatively simple, straightforward and extremely sensitive, it can be employed in environments where dissolved P levels are too low to obtain reliable P flux estimates using existing techniques. Lake Res. Lab., EAWAG/ETH, CH-6047 Kastanienbaum, Switzerland.

86:3954 Crosby, M.P., 1985. The use of a rapid radiolabeling

method for measuring ingestion rates of detri- tivores. J. expl mar. Biol. Ecol., 93(3):273-283. Univ. of Maryland, Horn Point Environ. Lab., P.O. Box 775, Cambridge, MD 24613, USA.

86:3955 Moore, J.C., D.J. Hansen, R.L. Garnas and L.R.

Goodman, 1985. A sand/granular carbon filtra- tion treatment system for removing aqueous pesticide residues from a marine toxicology laboratory effluent. Wat. Res., 19(12): 1601-1604. U.S. EPA, Gulf Breeze, FL 32561, USA.

86:3956 Thayer, C.W., 1985. Quick-release cages and repet-

itive censusing of sessile epifauna. I . expl mar. Biol. Ecol., 94(1-3):251-257.

Quick-release cages are attached by Velcro to frames and placed over in-situ populations on rock of any orientation. These cages are strong, economical, and easily removed for cleaning and repeated censusing with minimal disturbance to the biota. Rawl-studs and quick-release cages permit in-situ studies in water depths approaching the limits of SCUBA. Dept. of Geol., Univ. of Pennsylvania, Philadelphia, PA 19104, USA.

E50. General biology, ecology, bioge- ography, etc.

86:3957 Barber, R.T., J .E Kogelschatz and F.P. Chavez,

1985. Origin of productivity anomalies during the

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D. Submarine geology and geophysics

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