Compound-Specific 14C Dating of IODP Expedition 318 Core U1357A Obtained Off the Wilkes Land Coast, Antarctica

Abstract

This study applied compound-specific radiocarbon analysis (CSRA) to a 186-m-long sediment core (U1357A) taken from Adélie Basin located on the continental shelf off Wilkes Land, East Antarctica. The CSRA targeted C16 fatty acid as well as C16., fatty acid and cyclopheophorbide-a-enol isolated from the sediment. Due to their high degradation rate, these compounds are expected to occur in low abundances in relict organic matter deposited at this site. Twelve compound-specific (CS) 14C ages were obtained that are mostly consistent with their stratigraphic order. The CS 14C results of all samples are Holocene in age (9800 to 440 cal BP). These results suggest that significant sedimentation started ∼10,000 cal BP. Moreover, the data suggest that 14C measurements of C16:1 fatty acid and cyclopheophorbide-a-enol are useful for dating sediments from the Southern Ocean.