MINERALOGICAL STUDIES OF MEDIUM TO HIGH GRADE METASEDIMENTARY ROCKS FROM MOUNT MITCHELL STATE PARK, NORTH CAROLINA, USA

Mount Mitchell became a state park in 1916 and after the late 1980’s and early 1990’s geological files regarding the mountain ceased being updated with new research findings. Although we know that Mt. Mitchell lies in the Ashe Metamorphic suite which contains metasedimentary rocks such as schist, gneiss and metagraywacke, updating these geological files on Mt. Mitchell could provide more in-depth information regarding the history of the mountain, especially in regards to how it was formed and what processes occurred to create it. Furthermore, updating the files for Mt. Mitchell State Park will allow staff to share the history and knowledge of the mountain to park visitors.

Samples for this study were collected from directly off of trails and outcrops around the semi-base of the mountain that is within the park boundary up towards the summit. Samples were crushed to create grain mounts and to isolate individual grains for mineralogical studies. Grain mounts were analyzed through a Polarized Light Microscope (PLM) and individual grains were analyzed through a spindle stage attachment on the PLM for further identification of the mineral. Samples are then cut into thin sections and placed on the PLM to observe microstructures and mineral identification. The Scanning Electron Microscope will be used to analyze carbon coated thin sections and sprinkle mounts for chemical composition and mineral assemblages using Electron Dispersion Spectroscopy. Thin sections of the rock samples will place chemical composition, mineral assemblages and microstructures into context with one another and can further describe the deformational events that created these types of rocks and minerals. Previous studies mainly focused on mineralogical analysis of grain mounts on a PLM and age dating of the rocks by using Potassium-Argon dating.

Preliminary examinations of a few samples show high heat and pressure minerals such as kyanite, garnet and sillimanite. Other minerals commonly found within these samples include, quartz, feldspar, micas, and amphiboles. An extensive rock and mineral report will be compiled and compared with existing geological data at Mt. Mitchell State Park. Temperature and pressures of the mountain’s formation environments are calculated and placed into context with other regional geological events.