RECORDS OF ICE RAFTED DETRITUS AND THEIR PALEOCLIMATIC IMPLICATIONS AT CHUKCHI BORDERLAND, WESTERN ARCTIC OCEAN

The depositional pattern of the Chukchi Borderland is rather complicated. The glacial-interglacial cycles greatly affected the development of the North American and Eurasian ice sheets and the pass way of Beaufort Gyre and its transport capability, and thus affected the origin of sediments in the Western Arctic Ocean. Multi-proxy investigations have been performed on cores of ARC4-BN03, ARC3-P37 and ARC4-MOR02 collected from the Chukchi Borderland, and compared with 6 other adjacent sediment records. Since MIS 5, several IRD events have been recognized in the Northwind Ridge (NR) area,which shows the contribution of Canadian Arctic Archipelago. During MIS 3, the sedimentation rate at the Chukchi Plateau (CP) and Chukchi Abyssal Plain (CAP) was higher than that on Northwind Ridge; besides the Canadian Arctic Archipelago, the IRD events may also had the contribution from Eurasian side. During MIS 2, the sedimentation rates in the CP and CAP collapsed due to the extended ice cap from the East Siberian Sea. The IRD input in these areas may mainly come from Eurasia and East Arctic marginal seas. In comparison, the IRDs at the NR are still originated from the Canadian Arctic Archipelago. The ice cap during glacial period prevented the transportation of North American materials to the CP and CAP. Then the NR region at the edge of the ice cap thus show greater sedimentation. During warm intervals, the IRD events of Chukchi Borderland have the contribution from the Canadian Arctic Archipelago.