The estimation of the mantle structure from OIB geochemical data analysis

Abstract

A prominent feature of the deep mantle is the presence of Large Low Shear Velocity Provinces (LLSVPs), characterized by negative shear wave velocity anomalies. Although the origin of these large-scale heterogeneities remains unclear, several hypotheses have been proposed as primordial mantle reservoirs, accumulations of subducted oceanic crust, or remnants of material delivered by a giant impact.In this study, we compiled geochemical data of ocean island basalts (OIBs) from the GEOROC database and estimated the source mantle of OIBs as a mixture of peridotitic and pyroxenitic component, in order to investigate mantle structure. Our results suggest that, geochemical evidence devides the deep mantle into two distinct domains as well as the mantle structures through seismic tomography.