Establishing the pattern of Holocene-LGM changes in sediment contributions from Antarctica to the Southern Ocean

By investigating long-lived radioactive decay systems, the sediment sources can be traced and the geological history of those sources can be delineated. The sediments deposited along the Antarctic coast represent a mixture of different lithologies that were incorporated progressively during glacial transport, and their composition reflects the variety of bedrock lithologies underlying different sectors of the ice sheet.

The different basement provinces yield distinctive isotopic signatures, and the sediments deposited in proximal regions of the Antarctic continent contain information about Antarctic basement ages and its geological evolution. This project represents a first attempt to document regionally integrated provenance signals and individual mineral ages of Antarctic sources to the Southern Ocean. We analyzed (1) Nd, Hf, and Sr isotope ratios and Sm/Nd ratios of terrigenous sediment from ~40 cores taken near the perimeter of the Antarctic continent, south of the Antarctic Divergence, and northward into the Antarctic Circumpolar Current; (2) K-Ar ages of >500 individual detrital hornblende crystals from a subset of the core samples; and (3) Hf isotope ratios of Circum-Antarctic Fe-Mn crusts that were previously analyzed for Pb and Nd isotope ratios (Abouchami and Goldstein, GCA, 1995 and Albarede, Goldstein Dautel, GCA 1997).