Petrographic and Geochemical Investigation of the Copper Hill and Gopher Ridge Volcanics in the Sierra Nevada Foothills, California

California has a complex geologic history including a series of orogenies partially represented by California has a complex geologic history including a series of orogenies partially represented by sequential volcanic terranes on the western coast of the North American Continent. Each orogeny resulted in accretion of several types of volcanic terranes. Accretion during the Jurassic Nevadan Orogeny is represented by arc volcanic suites. Among material accreted during the Orogeny is the Foothills Terrane. The Foothills Terrane within the Sierra Nevada Foothills contains volcanic arc suites represented by greenschist facies metamorphism. The focus of this investigation is the comparison of the Copper Hill and Gopher Ridge volcanics, two formations representing metamorphosed basalt and basaltic tuff material. The purpose of exploring the Copper Hill and Gopher Ridge Volcanic formations is to contribute to the increasing volume of knowledge about California’s complex geologic. Examination of these formations includes petrographic analysis. The analysis resulted in identification of mineralogical trends and textures. During analysis grain orientation due to tectonic activity and fluid flow within the rock during metasomatism was observed. Alteration of silicate minerals to carbonates in Gopher Ridge Formation was also observed. This observation resulted in the decision to run an XRD analysis on all samples. Presented on the poster are the results of both petrographic and XRD analyses