Ice sheet controls on fine-grained deposition at the southern Mendeleev Ridge since the penultimate interglacial

摘要

Clay minerals deposited at the southern Mendeleev Ridge in the Arctic Ocean have a unique provenance,which can be used to reconstruct changes in the local sedimentary environment.We show that sediments in core ARC7-E23 record high-frequency changes in clay minerals since the penultimate interglacial.The clay minerals,grain size,and ice-rafted debris indicate the extent of the East Siberia Ice Sheet(ESIS).During the glacial periods of Marine Isotope Stage 2(MIS2)and MIS4,the southern Mendeleev Ridge was likely covered by an ESIS-extended ice shelf,blocking almost all sediment input from the Canadian Arctic and Laptev Sea,but allowing transport of fine-grained sediments from the East Siberian and Chukchi Sea shelves.After ESIS retreat,the Beaufort Gyre and Transpolar Drift became the primary transport mechanism for the distally sourced sediments.Climate conditions in MIS3 enhanced both the oceanic circulation and sediment transport.