Radiocarbon dating of individual fatty acids as a tool for refining Antarctic margin sediment chronologies.

Abstract

We have measured the radiocarbon contents of individual, solvent-extractable, short-chain (C (sub 14) , C (sub 16) , and C (sub 18) ) fatty acids isolated from Ross Sea surface sediments. The corresponding (super 14) C ages are equivalent to that of the post-bomb dissolved inorganic carbon (DIC) reservoir. Moreover, molecular (super 14) C variations in surficial (upper 15 cm) sediments indicate that these compounds may prove useful for reconstructing chronologies of Antarctic margin sediments containing uncertain (and potentially variable) quantities of relict organic carbon. A preliminary molecular (super 14) C chronology suggests that the accumulation rate of relict organic matter has not changed during the last 500 (super 14) C yr. The focus of this study is to determine the validity of compound-specific (super 14) C analysis as a technique for reconstructing chronologies of Antarctic margin sediments.