Reworked Paleocene and Eocene Foraminifera, Mac.Robertson Shelf, East Antarctica: Paleoenvironmental implications

Paleogene planktonic and benthic foraminifera, reworked into young Cenozoic sediments, are recorded from Mac. Robertson Shelf, east Antarctica. Paleocene and Eocene faunas include relatively warm water faunas and include Globanomalina pseudomenardii and Globigerinatheka kugleri. While all are minor components of the faunas, benthic species are more diverse and abundant than planktonic, and allow comparisons to be made with coeval southern Australian, New Zealand, and South American faunas, at a time when the continents were much closer together and Antarctica lacked the current icesheet. A new species of Ammoelphidiella represents the earliest occurrence of this Antarctic genus, and indicates that an Antarctic bioprovince existed for foraminifera, as had already been recognised in marine microplankton. The region yields evidence of relative warmth later than envisaged in some models of the early evolution of the Antarctic icesheet. Inoceramus prisms are evidence for some reworking of Cretaceous material but no undoubted Cretaceous foraminifera have been recovered. Paleogene shallow water marine sections on Mac. Robertson Shelf are a potential source of valuable information concerning the evolution of the Antarctic environment over this critical interval and for which such sections are few.