992 resultados para Baltic 75


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According to geochemical analyses carbonaceous sediments from deep basins of the Baltic Sea containing 3-5% of organic carbon are enriched in some metals such as Cu, Mo, Ni, Pb, Zn, V, and U relative to shallow-water facies of the Bay of Finland. These metals also enrich (relative to background values in clayey rocks) ancient carbonaceous shales, where the average Cu and V contents are slightly higher and that of Mo, Pb, and Zn lower than in deep-sea carbonaceous sediments of the Baltic Sea. In addition, the deep-sea carbonaceous sediments of the Baltic Sea are enriched (but less notably than ancient shales) in Ag, As, Bi, and Cd. These data confirm previous assumptions that carbonaceous sediments accumulating now in seas and oceans can be considered as recent analogs of ancient metalliferous shales.

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A detailed topographic survey was carried out in the "Hausgarten"-area of the Joint Research Programm 95 of the University of Kiel by the Deutsches Hydrographisches Institut. Based on this information a sediment distribution map was constructed. A horizontal section extending from 0 to 27 m of water depth was investigated showing the distribution of pebbles and boulders, of algal growth, and exposed areas of glacial marl; the grain size distribution was determined for the various sediment types.

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Early diagenetic ultrastructural alterations of benthic foraminifers of the genera Elphidium and Ophthalmina from the shallow water sediments of the Kiel Bight were investigated by scanning electron microscopy. Pure solution patterns were deduced from supplementary experiments.//Several carbonate destroying processes can be specified by ultrastructural patterns of the shell surfaces. Based on these patterns three zones are established, each showing different mechanisms of shell fragmentation: 1) zone of abrasion, 2) zone of disintegration, 3) zone of corrosion. This zonation depends on the water depth and is caused primarily by water agitation and by under saturation of the bottom water with respect to carbonate.

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Distributions of free and bound n-alkanes, n-alkanoic acids, and n-alkanols were determined in order to compare the character of organic matter contained in organic-carbon-rich sediments from two sites sampled by the hydraulic piston corer. Two diatomaceous debris-flow samples of Pleistocene age were obtained from Hole 530B in the Angola Basin. A sample of bioturbated Pleistocene diatomaceous clay and another of bioturbated late Miocene nannofossil clay were collected from Hole 532 on the Walvis Ridge. Geolipid distributions of all samples contain large terrigenous contributions and lesser amounts of marine components. Similarities in organic matter contents of Hole 530B and Hole 532 sediments suggest that a common depositional setting, probably on the Walvis Ridge, was the original source of these sediments through Quaternary, and possibly late Neogene, times and that downslope relocation of these biogenic deposits has frequently occurred.