A GEOCHEMICAL ANALYSIS OF THE EAST-CENTRAL MINNESOTA BATHOLITH

The bedrock of South-Eastern Stearns County in Central Minnesota is composed of a number of intrusive igneous units that are associated with the post-tectonic phase of the Penokean Orogeny during the early to middle Proterozoic. It include two compositionally distinct granites, a granodiorite, an aplite dike, a porphyritic microgranite dike with Rapakivi texture, and two distinct sets of basalt dikes. In this study, XRF analyses of these rocks were conducted to determine the cooling histories and magmatic associations of these units. Additionally, the constituent minerals of these units were studied optically and with SEM/EDS to further corroborate the geochemical findings and provide more depth to the story of their petrogenesis.