The Ivory Coast microtektite strewnfield: new data

The Ivory Coast microtektite strewnfield: new data

780 C. Submarin©Geology and Geophysics 79:6000 Roddick, J. C., W. E. Cameron and A. G. Smith, 1979. Permo-Triassic and Jurassic 4~'Ar-~Ar ages from ...

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780

C. Submarin©Geology and Geophysics

79:6000 Roddick, J. C., W. E. Cameron and A. G. Smith, 1979. Permo-Triassic and Jurassic 4~'Ar-~Ar ages from Greek ophiolites and associated rocks. Nature, Lond., 279(5716): 788-790. Department of Earth Sciences, The University, Leeds, U.K. 79:6001 Sonnenfeld, Peter, 1978. Effects of a variable sun at the beginning of the Cenozoic era. Clim. Change, 1(4): 355-382. Staggered extinctions of terrestrial, marine and flying reptiles, and of invertebrate plankton feeders, accompanied by a decrease in worldwide aridity at the end of the Cretaceous, may be explained by periodic bursts of increased ultraviolet radiation, possibly the result of a long-term breakdown of the ozone layer. Includes ca. 130 references. University of Windsor. Windsor, Ontario N9B 3P4, Canada. (dine) 79:6002 Speed, R. C., L. C. Gerhard and E. H. McKee, 1979. Ages of deposition, deformation, and intrusion of Cretaceous rocks, eastern St. Croix, Virgin Islands. Bull. geol. Soc. Am.. (i)90(7): 629-632. St. Croix is the only exposure of the St. Croix platform above sea level, and is underlain by Late Cretaceous rocks that may have been deformed and intruded during events affecting the Greater Antilles between 64 m.v. and 74 m.v. Department of Geological Sciences, Northwestern University, Evanston, i11.60201, U.S.A. (dme)

8. Sedimentation, sedimentary processes and diagenesis 79:6003 Tambiev, S. B., 1979. Strontium and barium in the process of oceanic phosphorite formation. (In Russian: English abstract.) Okeanologiia, 19(2): 272-279. Strontium and barium concentrations are measured in phosphorites from shelves off Africa, Chile and Peru: from Pacific seamounts and in ocean bottom bone samples. Variation of Sr and Ba concentrations as a function of lithification, Sr/P20~ values for the different locations, and genesis of phosphorites from seamounts are discussed. (rio)

9. Bottom sediments, sedimentary rocks and formations (type, composition, etc.) 79:6004 Crocket, J. H. and H. Y. Kuo, 1979. Sources for gold,

OLR(1979)26(12)

palladium and iridium in deep-sea sediments. Geochim. cosmochim. Acta, 43(6): 831-842. Noble metal concentrations are determined in four Caribbean and Pacific-Antarctic Basin deep-sea cores which include siliceous and calcareous oozes and pelagic clays. The primary goal is to test the relative importance of biogenic and lithogenic processes in the budgets of these metals. Alternative sources and sinks are briefly considered. Department of Geology, McMaster University, Hamilton, Ontario LSS 4M1, Canada. (rio) 79:6005 Glass, B. P. and P. A. Zwart, 1979. The Ivory Coast microtektite strewnfield: new data. Earth planet. Sci. Letts, 43(2): 336-342. Microtektites in piston cores from the Atlantic Ocean are part of the Ivory Coast (IVC) tektite strewnfield which covers an area of about 4.5 million square kilometers. The IVC microtektite layer is found near the base of the Jaramillo geomagnetic event, and may be associated with it. Department of Geology, University of Delaware, Newark, Del. 1971 I. U.S.A. (dine) 79:6006 Stanley, D. J., Harrison Sheng and M. M. Kholief, 1979. Sand on the southern Mediterranean Ridge: proximal basement and distal AfricanNile provence. Nature, Lond., 279(5714): 594-598. Distinct mineralogical differences occur between Quaternary sediments from the Egyptian shelf-Nile Cone region and the southern part of the Mediterranean Ridge, and indicate a more complicated provenance dispersal than previously thought. Figures include mineral micrographs. Division of Sedimentology, Smithsonian Institution. Washington, D.C. 20560, U.S.A. (dme)

10. Coasts, beaches and marshes 79:6007 Chappell, J., 1. G. Eliot. M. P. Bradshaw and E. Lonsdale, 1979. Experimental control of beach face dynamics by watertable pumping. Engng Geol., 14(I): 29-41. Artificial lowering of the beach watertable appears to promote sand accretion on the beach face and may prove useful for shore-zone management on coastlines where conservation of sand above the surf zone is a problem. Department of Geography, S.G.S., Australian National University, Canberra, A.C.T. Australia. (dme) 79:6008 Pingree, R. D. and D. K. Griffiths, 1979. Sand trans-