Heat-flow determinations of basement age in small oceanic basins of the southern central Scotia Sea

Results are reported from seven heat flow stations in small basins of the southern part of the central Scotia Sea (CSS), undertaken in order to determine basement ages. The basins are small, which makes magnetic anomaly-based ages ambiguous and preserves basin subsidence that may have been anomalous as a result of local factors. The fact that these small basins formed in a back-arc setting adds additional uncertainty to depth-based age estimates. The results confirm that basin extension commenced in the Eocene, and indirectly support a relatively young, back-arc origin for the northern CSS, but do not affect previously published suggestions of the age of onset of the Antarctic Circumpolar Current.