Radiocarbon ages of sterols and of total organic carbon from Weddell Sea and Gerlache Strait sediments

Sterols in a core from the Schollaert Drift, Gerlache Strait,
Antarctica can be used successfully to determine the ages of sediment
horizons. It has, however, not been possible to extend this work to
numerous samples of interest from the Greenpeace Trough and the region
of the Larsen Ice Shelf. Of 38 samples analyzed, 26 contained less
than 0.05 ppm sterols (ppm = ug sterol/g dry sediment) and only six
contained more than the practical threshold of 0.3 ppm. All of the
latter were from core tops and thus not important targets for dating.
In contrast, samples from temperate and tropical latitudes with ages
up to 250,000 years rarely contain less than 1 ppm and frequently
contain more than 10 ppm sterols. Low concentrations of appropriate
biomarkers are a major problem in Antarctic sediments.

A publication describing these results and integrating them with
oceanographic and sedimentological conditions in the Weddell Sea will
be prepared as soon as total-organic-carbon dates from all locations
are available.