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. ***
