The earth’s mantle is primarily composed of a rock called peridotite. Subduction results in the reinjection of basaltic crust into the mantle, which is metamorphosed into a rock called eclogite. The extent of lithological heterogeneity has implications for the rate of convective stirring and chemical homogenization of the mantle but is not well-constrained. Basaltic melts extracted from the mantle carry geochemical information about the composition of the mantle, most clearly through their trace element and isotopic signatures. This experimental study provides measurements of the partitioning of the first-row transition elements (FRTE) between eclogite and melt, which could be used to fingerprint the source lithology of ocean island basalts (OIB) and infer participation of recycled lithologies in their generation. My simple forward melting modeling shows that partial melts of peridotite match OIB FRTE signatures just as well as melts from mixed peridotite plus eclogite sources, but there are some signatures that are not well matched by either.
University of Minnesota M.S. thesis. October 2020. Major: Geological Sciences. Advisor: Frederick Davis. 1 computer file (PDF); vi, 97 pages.
Experimentally generated partition coefficients for the first-row transition elements during eclogite partial melting at three gigapascals.
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