VARIABILITY IN RADIOCARBON AGES OF INDIVIDUAL ORGANIC-COMPOUNDS FROM MARINE-SEDIMENTS

Organic carbon (OC) from multiple sources can be delivered contemporan eously to aquatic sediments. The influence of different OC inputs on c arbon-14-based sediment chronologies is illustrated in the carbon-14 a ges of purified, source-specific (biomarker) organic compounds from ne ar-surface sediments underlying two contrasting marine systems, the Bl ack Sea and the Arabian Sea, In the Black Sea, isotopic heterogeneity of n-alkanes indicated that OC was contributed from both fossil and co ntemporary sources. Compounds reflecting different source inputs to th e Arabian Sea exhibit a 10,000-year range in conventional carbon-14 ag es. Radiocarbon measurements of biomarkers of marine photoautotrophy e nable sediment chronologies to be constructed independent of detrital OC influences.