Plagioclase Peridotites in Ocean^Continent Transitions: Refertilized Mantle Domains Generated by Melt Stagnation in the

The existence of different mantle domains exposed in ocean^ continent transition zones provides a framework for understanding the generation of ultramafic seafloor along magma-poor rifted mar-gins. In this study we present detailed petrological and geochemical data on peridotites from the Eastern Central Alps ophiolites in Switzerland and Italy to identify different mantle domains, to esti-mate the extent of refertilization, and to test whether refertilization is associated with a thermal signature that has important implica-tions for geophysical interpretations of ocean^continent transitions. The compositions of clinopyroxene, orthopyroxene and spinel clearly reflect the different mantle domains. Relative to clinopyroxenes from spinel peridotites, clinopyroxenes from plagioclase peridotites have lower Na2O and Sr contents, but higher middle to heavy rare earth element ratios and Zr concentrations, and different Sc^V relation-ships. Spinels in plagioclase peridotites have higherTiO2 and lowe