Systematic variation of the Os isotope ratios and PGE abundances in the drilling core samples from the mantle transition zone recovered from the Oman Drilling Project

Abstract

Understanding the structure and evolution of the oceanic plate and the upper mantle is important for understanding the earth's material circulation and global inner earth system. The purpose of this study is to estimate elemental transfer at the crust-mantle boundary and melt extraction ages of the upper mantle to analyse siderophile platinum group elements (PGEs) and Os isotope compositions using samples from the CM site of the Oman Drilling Project, which directly drilled the crust-mantle boundary. The data from the harzburgites of the CM site show flat PGE patterns and low Os isotope ratios. On the other hand, dunite shows a large variation in all PGEs and a relatively high Os isotope ratio, suggesting melt coexistence. Combining the results of the gabbro, which forms the lower crust, we will compare the crust-mantle boundary materials.