Geochemistry and Petrology of the Mesoproterozoic Katemcy Pluton, Llano Uplift, Central Texas

The Katemcy pluton is an A-type granite that is peraluminous, to slightly metaluminous, ferroan, alkalic to alkali-calcic. Mesoproterozoic igneous body emplaced within the westernmost Llano Uplift in central Texas during the Grenville orogeny. Geochemical analysis of the samples shows that the Katemcy is compositionally consistent with minor differences in concentrations of accessory minerals (ie. muscovite, garnet, magnetite, zircon and amphibole). Determination of whether the Katemcy pluton is part of the Lone Grove complex or consistent with the Younger Granites was done through the geochemical analysis of forty-two Katemcy samples compared to samples previously analyzed from the Lone Grove and the Younger Granite bodies within the uplift. The Katemcy shows similarities to the Younger Granites, however the Katemcy underwent a separate evolution due to magma mixing. Magma mixing and disequilibrium can be confirmed by myrmekite, granophyre and rapakivi disequilibrium textures found within the Katemcy samples. Katemcy granite may have been produced from the same source as the Younger Granites, but, underwent a separate fractionation pathway due to magma mixing.