MINERALOGICAL AND STRUCTURAL CHARACTERIZATION, AND CONSTRAINTS ON PROVENANCE, OF THE SHINING ROCK QUARTZITE, SHINING ROCK MOUNTAIN, HAYWOOD COUNTY, NORTH CAROLINA

Shining Rock is the namesake formation of the Shining Rock Wilderness, located in the Eastern Blue Ridge geologic province of southwestern North Carolina. Shining Rock itself is a highly unusual kilometer-scale formation of bright white quartzite. The overall white coloration produced by the mass of small quartz crystals is punctuated with areas of red/pink/yellow coloration. Geologic mapping, optical and electron microscopy, and x-ray diffraction were combined to characterize this previously uncharacterized body and constrain the provenance of the unit. The quartzite was determined: to be composed almost entirely of quartz, with grains predominantly 0.6 – 1.5 mm in size; to be metamorphosed to upper-amphibolite facies (sillimanite grade); and to conform both structurally and metamorphically with surrounding rocks of the Ashe Metamorphic Suite/Tallulah Falls formation (AMS/TF). Based on these data, the authors conclude the Shining Rock quartzite is likely metasedimentary in origin and formed as a unit of the AMS/TF from a protolith of mature quartz arenite, likely sourced from a well-sorted beach or dune in the Late Proterozoic Iapetus Ocean basin. Together with the surrounding formations, it would have been transported during the Taconic orogeny onto the Laurentian landmass, deeply buried and metamorphosed, and later transported into its current location as part of the Alleghanian orogeny’s Blue Ridge-Piedmont Megathrust Sheet.