9416620 Hart This project will address a long-standing problem of excessively high Sr isotopic ratio in oceanic peridotites by testing the hypothesis that this signal results from the presence of particles derived from continental crust and carried deep into the peridotites by circulating seawater. The hypothesis will be tested by analyzing other isotopic systems, including Nd, Pb, Os and Be. Confirmation of the hypothesis would have major implications for global, and oceanic, biochemical cycles and fluxes. ***
