Sedimentation process in the deep-sea region of the Bellingshausen Sea in association with ice sheet dynamics

Abstract

Two sediment cores, 2.2 m-long core BS17-GC01 (67o22.8947´S, 96o23.2464´W, 4627 m deep) and 8.5 m-long core BS17-GC02 (68o09.4940´S, 94o34.7988´W, 4361 m deep), were collected from the deep basin off the Bellingshausen Sea during ANA07D cruise by Araon. Since core BS17-GC01 was collected from more distal location from the Belgica Fan than the other, their sedimentary differences would provide important information on deposition pattern with distance in response to ice sheet advance/retreat. The age model for core BS17-GC01 was constrained by graphic correlations with EDML ice core dust record and that for core BS17-GC02 was constrained by AMS 14C dates and additional sediment color correlation with core BS17-GC01. Both cores showed color alternation of brown and gray, although core BS17-GC02 has thick laminations. The brown layers are thought to be deglacial-interglacial deposition, whereas the gray layers are considered to be glacial deposition. In spite of similar sediment color variation, there were some clear distinctions in geochemical and sedimentological records between two cores indicating differences in sedimentary process with distance from the continental shelf. Our record suggests that a large amount of shelf sediments is transported into the deep-sea region during the deglacial period indicating that sub-glacial melting/pumping can be an important mechanism to transport shelf sediments to the deep sea off the Bellingshausen Sea.