A NEW 1:24,000-SCALE GEOLOGIC MAP OF THE SOUTHERN HALF OF THE MOUNT MITCHELL 7.5-MINUTE QUADRANGLE, YANCEY AND BUNCOMBE COUNTIES, NORTH CAROLINA
The AMS lithologies on the quadrangle include metagraywacke, schistose metagraywacke, aluminous porphyroblastic migmatite, garnet-mica schist, amphibolite, and altered ultramafic bodies. These lithologies are complexly deformed, interlayered, and migmatitic. Amphibolite and associated ultramafic bodies occur as relatively thin discontinuous lenses that are commonly on-strike with one another. Many of these are too small to show at 1:24,000-scale. The aluminous migmatite is characterized by medium- to coarse-grained leucosome with kyanite, up to 6 inches in length, and porphyroblastic muscovite. The AMS lithologies on the quadrangle have been metamorphosed to upper amphibolite facies. Kyanite and sillimanite are abundant in the migmatite and schist units.
Compositional layering and schistosity are parallel to one another and complexly folded in the study area. Foliations typically strike NE-SW and dip moderately to steeply to the NW and SE. Joint data indicate a prominent, steeply-dipping, WNW-trending fracture set. Whole rock geochemical analyses (57 elements) were performed for ten representative samples. Five stream sediment samples from relatively unmodified watersheds were analyzed to determine heavy mineral concentrations.