INVESTIGATION OF TI BEARING AND NON-TI BEARING BIOTITES COEXISTING IN METAPELITE SCHISTS FROM MOUNT MITCHELL, NORTH CAROLINA

The research analyzes rock samples from Mount Mitchell State Park, North Carolina and determines the chemistry of biotite minerals within, specifically for titanium content. A previous study of the rocks at Mount Mitchell analyzed a sample containing biotite both with and without titanium. Two different compositions of biotite coexisting within a rock potentially suggests two separate crystallizations of the mineral. Measuring the chemical composition of the biotite found in these rocks aids in constraining the temperature and pressure range for the metamorphism of the rocks, especially if these rocks are a product of two separate events.

Multiple samples were collected from the outcrop at Mount Mitchell’s summit known to contain both compositions of biotite as well as from multiple outcrops along a nearby trail with a permit from the state park. Polished thin sections of the samples are analyzed by Energy Dispersive Spectroscopy (EDS) on the Scanning Electron Microscope (SEM) as well as observing optical properties through the Polarized Light Microscope (PLM). This project obtains preliminary data to determine which samples contain both chemistries of biotite as well as note other distinguishing characteristics between the two. Future research will obtain precise chemical composition of the samples by Wavelength Dispersive Spectroscopy (WDS).

Much of the current information about the geology in this region is outdated and this research will provide modern microphotographs and compositional data of these rocks. This information will allow the geologic history of Mount Mitchell to be placed in context with surrounding geology and related studies and provide data and information specific to this state park for their records as well as for the scientific community.