THE MINERALOGY AND GEOCHEMISTRY OF A PEGMATITE POCKET WITHIN THE ELKAHATCHEE QUARTZ DIORITE, ALABAMA

The Elkahatchee Quartz Diorite (EQD) hosts pegmatite pockets near Hog Mountain in Tallapoosa County, AL, within the southernmost Appalachian Mountains. This area lacks fine-scale mapping, and the pegmatite pockets are uncharacterized. Pegmatites can contain a variety of mineral sizes but are typically coarse-grained and/or zoned and are thought to form during the late stages of magma evolution. This potentially leads to a higher concentration of incompatible elements within pegmatites, which may include lithium (Li) and rare earth elements (REEs) that are considered to be critical minerals needed for the economy and domestic security. This encompasses materials required to manufacture and support items in Americans’ daily lives such as electronics, cars, medicine, and in the growth of renewable energy sources. Pegmatites are also economically important for industrial materials and gem-quality minerals. This research aims to identify the mineralogy, extent, and elemental composition of the EQD pegmatite pockets, which will offer clues about how they formed. X-ray diffraction and electron microprobe analysis will be performed to identify the mineralogy and geochemical composition of a preliminary sample set. Mineral relationships and additional identification will be determined using transmitted light microscopy. Initial investigation indicates that the EQD pegmatite pockets near Hog Mountain are primarily composed of biotite + muscovite + quartz + feldspar. They are coarse-grained (up to ~3 cm) with some oriented crystal growth. Studying the EQD pegmatite pockets will not only provide information about these understudied rocks, but also contribute to our general understanding of pegmatite formation. Future work will include field mapping and additional sampling of the EQD around Hog Mountain.