Acquiring Bulk Compositions of Spinel Peridotite Xenoliths Using GIS and Digital Image Processing Techniques

Abstract

This study investigates the viability of using GIS techniques to estimate modal abundances of minerals in thin sections of peridotite and uses this data to calculate bulk chemical compositions of peridotitic mantle xenoliths from Oahu, Hawaii to determine their provenance. To answer these questions, I performed classifications using ArcGIS on nine xenolith samples to determine their modal abundances, which were then used to calculate their bulk chemical compositions. My results show that GIS has the potential to be a useful tool for non-destructive analysis of modal abundances. They also support a role for melt-rock reaction occurring between migrating melts and peridotite in the oceanic lithospheric mantle, resulting in the production of dunites. This study is a first step in utilizing GIS to assist with thin section analyses and fills a gap in existing chemical data for Hawaiian mantle xenoliths.