Sound velocity and related properties of marine sediments

Sound velocity and related properties of marine sediments

OLR(1983)30 (6) D. SubmarineGeologyand Geophysics Factors affecting sediment consolidation and rock formation in terrigenous, carbonate and siliceou...

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OLR(1983)30 (6)

D. SubmarineGeologyand Geophysics

Factors affecting sediment consolidation and rock formation in terrigenous, carbonate and siliceous sediments of the littoral and shallow-water shelf, the upper slope and the ocean floor are discussed. Leningrad Univ., Leningrad, USSR. (msg) 83:3312 Mauviel, Anne, Huu-Van Nguyen, Roger Chesselet, Myriam Sibuet, Yuji Yokoyama and G~rard Auffret, 1982. Quantitative estimates of biological mixing rates of North Atlantic pelagic sediments using non-destructive gamma ray spectrometry (GeHP). Bull. Inst. G~ol. Bassin Aquitaine, 31/32:257-274. (In French, English abstract.) Centre Oceanol. de Bretagne, BP 33729273, Brest Cedex, France. 83:3313 McCave, I.N., 1982. Erosion and deposition by currents on submarine slopes. Bull. Inst. G~ol. Bassin Aquitaine, 31/32:47-55. Seabed morphology and current action on the Bermuda Rise's eastward scarp indicate that bed surface and acoustic subsurface characteristics are related to seabed gradient. Late Quaternary intensification of currents resulted in the development of small, steeper scarps and in the erosional recession of the upper gentle slopes of the rise. Sch. of Environ. Sci., Univ. of East Anglia, Norwich, UK. (hbf)

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to atmospheric particulates. Estimations of aluminosilicate fluxes indicate that much of this air-borne material is transported rapidly downward through the water column in fecal material. Accumulation rates of selected trace metals (Al, Fe, Mn, Co, Cu, Zn) are highest in marginal sediments and lowest in mid-ocean. Dept. of Oceanogr., The Univ., Liverpool L69 3BX, UK. (bwt) 83:3316 Gonthier, Eliane, J.-C. Faugeres and Jacques Poutiers, 1982. Sedimentary sequence of the Gibbs Fracture Zone: granulometric characteristics and dynamic process interpretation. Bull. Inst. G~ol. Bassin Aquitaine, 31/32:217-223. (In French, English abstract.) Inst. de Geol. du Bassin d'Aquitaine, Univ. de Bordeaux 1, 351 cours de la Liberation, 33405 Talence Cedex, France. 83:3317 Hamilton, E.L. and R.T. Bachman, 1982. Sound velocity and related properties of marine sediments. J. acoust. Soc. Am., 72(6):1891-1904. Laboratory measurements of sound velocity, density, porosity, grain density, and grain size of cores from the main ocean basins and seas show that mean size of mineral grains, or average porosity, usually will predict average sound velocity within 1-2%. Regression equations are given for the empirical relationships; procedures for correcting laboratory to in-situ values are detailed. Naval Ocean Systems Center, San Diego, Calif. 92152, USA. (mwf)

D130. Sediments (rocks, formations, type, composition, etc.) 83:3314 Bellaiche, Gilbert and Michel Hoffert, 1982. Sedimentary deposits of the inner floor of the rift and transform fault 'A' (FAMOUS area): in-situ observations by submersibles and sample analyses. Bull. Inst. G~ol. Bassin Aquitaine, 31/32: 225-237. (In French, English abstract.) Lab. de Geodynamique sous-marine 06230, Villefranche-sur-Mer, France. 83:3315 Chester, R., 1982. Regional trends in the distribution and sources of aluminosilicates and trace metals in recent North Atlantic deep-sea sediments. Bull. Inst. G~ol. Bassin Aquitaine, 31/32:325-335. The supply of land derived material to the midNorth Atlantic between 5°N and 35°N is dominated by aeolian transport as quartz and clay mineral distribution patterns in the sediments can be related

83:3318 Lonsdale, Peter, 1982. Sediment drifts of the northeast Atlantic and their relationship to the observed abyssal currents. Bull. Inst. G~ol. Bassin Aquitaine, 31/32:141-149. Two major bodies (Gardar and Feni drifts) of Miocene and younger sediment have been deposited and shaped by southward-flowing currents derived, in part, from dense Norwegian Sea outflows. Other drifts in this region underlie northward-flowing currents; Hatton Drift (west Rockall Plateau) and a small continental rise along Porcupine Bank are swept by currents that flow toward the Norwegian Sea. Parts of the lower continental rise of Northwest Africa also have regular depositional and erosional bedforms shaped by northerly flow. All these bottom currents are elements of a major cyclonic circulation which receives Norwegian Sea Water but is not driven by that outflow. Implications for models of Quaternary circulation and sediment dispersal are noted. Scripps Inst. of Oceanogr., Marine Physical Lab., La Jolla, Calif. 92093, USA.