IDENTIFICATION OF MINERALS IN SULFIDE BODY WITHIN GRANITE HOST AT NORTH BUNCOMBE QUARRY IN WESTERN NORTH CAROLINA

The objective of this research is to identify the minerals present in samples of a sulfide body found within the host granite at the North Buncombe Quarry in western North Carolina. The geologic setting of the research area is the late Proterozoic aged Ashe Metamorphic Suite (AMS), which is underlain by the Mesoproterozoic aged Grenville basement. The quarry is mining out of a granitic intrusion within the AMS. Quarry operations have met the contact zone between the AMS and the Grenville basement, where they have encountered the sulfide body. The AMS, which makes up a majority of surface rocks in the area, is composed of highly metamorphosed schists and gneisses and some intrusions of ultramafic and granitic rocks. The much older Grenville basement is composed mostly of metamorphic rocks.

In August 2016, the quarry came across a body of unidentified rock within the granite formation and impeding mining operations. Samples of the deposit exhibit mild magnetism and metallic luster. Preliminary analysis has identified the majority of the body to be pyrrhotite with the presence other sulfide minerals. This study identifies all of the minerals present and their approximate amounts by use of X-ray diffraction (XRD), reflective light microscopy, and backscattered electron (BSE) imaging and energy dispersive spectroscopy (EDS) using a scanning electron microscope (SEM).