Glacial–interglacial variations in Quaternary production of marine organic matter at DSDP Site 594, Chatham Rise, southeastern New Zealand margin |
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| Authors: | Elizabeth A Kowalski Philip A Meyers |
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| Institution: | Program in Marine Geology and Geochemistry, Department of Geological Sciences, The University of Michigan, Ann Arbior, MI 48109-1063, USA |
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| Abstract: | CaCO3 and total organic carbon concentrations, organic matter C/N and carbon isotope ratios, and sediment accumulation rates in late Quaternary sediments from DSDP Site 594 provide information about glacial–interglacial variations in the delivery of organic matter to the Chatham Rise offshore of southeastern New Zealand. Low C/N ratios and nearly constant organic δ13C values of ?23‰ indicate that marine production dominates organic matter supply in both glacial and interglacial times during oxygen isotope stages 1 through 6 (0–140 ka) and 17 through 19 (660–790 ka). Increased organic carbon mass accumulation rates in isotope stages 2, 4, 6, and 18 record enhanced marine productivity during glacial maxima. Excursions of organic δ13C values to ca. ?29‰ in portions of isotope stage 2 suggest that the local concentration of dissolved CO2 was occasionally elevated during the last glacial maximum, probably as a result of short periods of lowered sea-surface temperature. Dilution of carbonates by clastic continental sediment generally increases at this location during glacial maxima, but enhanced delivery of land-derived organic matter does not accompany the increased accumulation of clastic sediments. |
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| Keywords: | nerve fiber protein synthesis RNA protein |
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