Dispersal History of Ice-Rafted Detritus in the Arctic Ocean (700KA to Present)

9321487达比奖支持对北冰洋活塞式和箱式岩芯沉积物的持续沉积学研究。该方法利用岩屑、重矿物的岩相学分析，以及不透明铁颗粒的反射光岩相学和显微探针分析，对北极周围的沉积物岩芯和潜在的物源区进行了对比研究。统计方法有助于比较来自沉积物岩心和潜在物源区的岩石学和化学数据，以确保沉积物和物源的最佳匹配，以确定沉积物质的来源。用这种方法确定的沉积物来源是推断输运途径的基础，岩石学特征被用来推断输运机制。该项目将使用现有材料以及将在1994年夏天北冰洋部分巡航期间收集的岩芯。其目标是：1)确定最近的主要冰川和非冰川事件的冰筏沉积物的来源，并推断过去18 000年间北冰洋表面的环流模式；2)推断较旧的冰筏事件的漂移模式；3)评估受污染的俄罗斯河流沉积物的潜在分布，这些沉积物被海冰漂流重新分配；以及4)扩大北冰洋沉积物来源的数据库。这项工作是关于北冰洋沉积的基本信息，代表着对地质信息的重大投资，这些信息将对关注北极过去气候和最近活跃的地质过程的其他项目有价值。***

9321487 Darby This award supports a continued sedimentological study of sediment from piston and box cores from the Arctic Ocean. The method employs petrographic analysis of lithic fragments, heavy minerals, and reflected light petrography and microprobe analysis of iron- opaque grains in a comparative study of sediment cores and potential source areas around the Arctic. Comparison of the petrographic and chemical data from the sediment cores and potential source areas is facilitated by statistical methods to ensure best-fit matches of sediment and source for determining the origin of sedimentary material. Sediment provenance determined in this way forms the basis of inferences about transport pathways and the petrographic characteristics are used to infer transport mechanisms. This project will use existing material as well as cores to be collected during the Arctic Ocean Section cruise in the summer of 1994. The goals are to 1) determine the source of ice-rafted sediment for the latest major glacial and deglacial events and to infer Arctic Ocean surface circulation patterns during the last 18,000 years; 2) infer the drift patterns for older ice-rafting events; 3) assess the potential distribution of contaminated sediment from Russian rivers which are redistributed by sea-ice rafting; and 4) expand the database from which sediment provenance for the Arctic Ocean is derived. This work is basic information about sedimentation in the Arctic Ocean and represents a significant investment in geologic information that will be valuable for other projects focusing on past climates and recent geologic processes active in the Arctic. ***