Melting and reaction with melt/fluid in the basal peridotite of the northern Oman ophiolite

Abstract

Using clinopyroxenes REE contents and the open system melting model of Ozawa (2001) we examined the process in which Oman peridotites with high Cr# spinel were formed by flux melting of harzburgite. Positive correlation was acquired between the Ce/Yb ratio of clinopyroxenes and the Cr# of spinels for peridotites from the Salahi mantle section. Flux melting of peridotite with low Cr# spinel by infiltration of fluid enriched in LREE can explain such signature. Peridotites with spinel Cr# less than 0.5 were distributed along a shear zone, and their clinopyroxenes are depleted in LREE as residues after lherzolite melting under mid-ocean-ridge.