Compound-specific radiocarbon dating of Ross Sea sediments: A prospect for constructing chronologies in high-latitude oceanic sediments

We present an overview of the problems relating to the development of sedimentary chronologies for Antarctic margin sediments, and review the recent application of compound-specific radiocarbon dating methods for resolving them. Radiocarbon dating of solvent-extractable, short-chain (C14, C16, and C18) fatty acids isolated from surface sediments of the Ross Sea, Antarctica, revealed their ages to be consistent with that of the modern dissolved inorganic carbon (DIC) reservoir age (pre-bomb, Δ14C≈−150‰; post-bomb, Δ14C≈−100‰) in this region. This contrasts sharply with the radiocarbon ages of bulk organic matter in the corresponding sediments are substantially older (Δ14C=−298‰ to −712‰). Furthermore, the radiocarbon ages of these fatty acids progressively increase with the core depth. These results clearly show a utility of the compound-specific radiocarbon dating for developing sediment chronologies in the Antarctic margin sediments. This approach is potentially applicable to Arctic Ocean, as well as other areas of Southern Ocean where similar interferences by fossil or pre-aged carbon inputs have hindered the progress in the development of late Quaternary paleoceanographic records.