Publication Date:
2024-01-09
Description:
A multiproxy geochemical study of nine sapropel layers from ODP Hole 964A, ODP Leg 160 in the eastern Mediterranean spanning the Pliocene-Holocene time interval provides new insights into the evolution of sapropel deposition. Paleoenvironmental proxies were used for reconstruction of productivity (Ba derived from marine barite), oxygen conditions (trace metal ratios) and sedimentary regime (clay minerals, detrital elements). These proxies reveal a significant increase in river runoff relative to decreasing aeolian input during sapropel deposition over the whole time interval. Ba excess supports the argument that a significant increase in export productivity is the main triggering mechanism for sapropel deposition, although preservation also played an important role. Furthermore, major differences exist in depositional conditions, including both oxygenation and productivity since the Pliocene. Productivity fluctuated substantially and was higher during the Pliocene and Pleistocene than during the Holocene; at the same time decreasing oxygen availability parallels the enhanced productivity. Dysoxic to anoxic conditions appear to coincide with marine productivity maxima, thus suggesting that oxygen depletion may be linked to greater consumption rather than restricted circulation. This correspondence supports the hypothesis that productivity fluctuations resulting from climate oscillations were the main cause of enhanced organic matter contents and also a main controlling factor for reduced oxygen availability.
Keywords:
-; 160-964A; Accumulation rate, mass; Accumulation rate, total organic carbon; Barium/Aluminium ratio; Calcite; Carbon, organic, total; Cobalt/Aluminium ratio; Comment; Density, dry bulk; DEPTH, sediment/rock; DRILL; Drilling/drill rig; Eastern Basin; Joides Resolution; Lanthanum/Lutetium ratio; Leg160; Manganese/Aluminium ratio; Molybdenum/Aluminium ratio; Nickel/Aluminium ratio; Nickel/Cobalt ratio; Ocean Drilling Program; ODP; Sedimentation rate; Size fraction 〈 0.002 mm, clay; Uranium/Thorium ratio; Uranium authigenic index; Vanadium/(Vanadium+Nickle) ratio; Vanadium/Chromium ratio; Vanadium/Scandium ratio; Zirconium/Aluminium ratio
Type:
Dataset
Format:
text/tab-separated-values, 3582 data points
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