9628703 Walker The PIs propose to test core-mantle exchange in the Earth using the Pt-Os isotope system to study rocks which are believed to have been brought to the Earth's surface in mantle-derived plumes. If successful, 1860s anomalies in plume-derived materials may provide the only direct test of core-mantle interaction. The proposed study of Os and Pt isotopic systematics will be made on an array of mantle-derived rocks as well as on mantle and crustal rocks that may be recycled into the mantle, to determine if excess Os in plume-derived materials can be used as a test of core-mantle interaction. ***
