Composition of bottom sediments from Core SO201-2-101, Shirshov Ridge, Bering Sea

Analysis of lithology, grain-size composition, clay minerals, and geochemistry of Upper Pleistocene bottom sediments from the submarine Shirshov Ridge (Bering Sea) showed that the Yukon-Tanana terrane of the Central Alaska was main source area of the sediments. Sedimentary material was transported by the Yukon River through Beringia up to the shelf break, where they were entrained by a strong north-west sea current. Lithological data revealed several pulses of ice-rafted debris deposition roughly synchronous with Heinrich events and periods of weaker bottom current intensity. Based on geochemical results we distinguished intervals of an increase in paleoproductivity and extension of the oxygen minimum zone. Our results suggest that there were three stages of deposition driven by glacioeustatic sea-level fluctuations and glacial cycles in Alaska.对取自白令海海底舍尔绍夫海岭（Shirshov Ridge）晚更新世海底沉积物的岩性、粒度组成、黏土矿物及地球化学特征开展分析，结果显示阿拉斯加中部的育空-塔纳纳地体（Yukon-Tanana terrane）是该套沉积物的主要物源区。沉积物质经育空河通过白令陆桥搬运至陆架坡折地带，随后被强劲的西北向海流裹挟搬运。岩性数据揭示了多期冰筏碎屑沉积脉冲，其大致与海因里希事件（Heinrich events）及底层海流强度减弱时段同步。基于地球化学分析结果，本研究识别出古生产力升高与缺氧最小带扩张的沉积区间。研究结果表明，受阿拉斯加地区冰盖型海平面波动与冰川旋回驱动，该区域沉积物沉积共经历三个阶段。