Hellenic Trench sedimentation: An approach using terrigenous distributions |
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| Authors: | Peter H Feldhausen Daniel Jean Stanley |
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| Institution: | 1. NUS Corporation, 4 Research Place, Rockville, MD 20850 U.S.A.;2. Division of Sedimentology, Smithsonian Institution, Washington, D.C. 20560 U.S.A. |
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| Abstract: | Sand-sized terrigenous material from 450 samples representing 24 piston cores is used to compare slope, perched slope basin, and trench apron, plain and margin depositional environments within the Hellenic Trench west of the Peloponnesus. Recognition of three stratigraphically defined layers in the core sections served as a basis for evaluating changes in time. Statistical testing showed that within the upper defined layer (0–5700 yrs. B.P.) terrigenous grains are distributed rather uniformly throughout the slope and basin complexes in contrast to distributions in underlying layers (5700–17,000 and 17,000–45,000 yrs. B.P., respectively. These distributions reflect intense reworking by gravitative processes as evidenced by sediment structures, incomplete slope sections, high accumulation rates, and dilution of sapropels. The homogeneity of the upper layer is explained by failure and downslope transport of sediments that were deposited on the slope during lower stands of sea level. The quantitative analyses performed highlight the rapidity by which land-derived sediments by-pass high-relief slopes, temporarily reside in perched basins on the slope, and ultimately are dispersed to distal trench apron and basin environments by sporadic gravity flows. |
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