21. BIOLOGICAL MARKER SIGNIFICANCE
OF ORGANIC MATTER ORIGIN IN SAPROPELS
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ABSTRACTThe major extractable lipid components in a series of Pleistocene–Pliocene sapropels from Ocean Drilling Program Leg 160 Site 969 were investigated. The organic-carbon contents in sapropels of Pleistocene age have a typical range of values, up to 7.4%, whereas the Pliocene sapropels were extraordinarily organic-carbon rich with values reaching 32.2%. The molecular composition of extractable lipids was dominated by alkandiols and alkanolones, alkenones, and sterols, with lower amounts of n-alkanes and n-alcohols. The molecular compositions indicate that organic matter in sapropels is predominantly derived from marine algal sources. Nevertheless, the distribution of terrestrial lipids indicates a significant land-derived influx during sapropel formation. |
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