In situ foraminifera in grounding zone diamict: a working hypothesis

Abstract

AbstractThe ice-proximal diamict sediment deposited on the foreset of a grounding zone wedge in Glomar Challenger Basin on the eastern Ross Sea continental shelf yielded a low abundance assemblage of foraminifera at two piston core sites. We found 302 small well-preserved specimens representing 18 species of benthic foraminifera from 825 ml of sediment. Only three poorly preserved specimens of the planktonic foraminifera Neogloboquadrina pachyderma (sinistral) were found. Our combined analyses of preservation state, assemblage composition and stable isotopes suggest that the benthic foraminifera may be in situ. This possibility is of interest to palaeoclimatologists who use ice-proximal sediments on the Antarctic continental shelves to radiocarbon date the post-glacial retreat history.