Ophiolite of the Buck Creek/Chunky Gal Mountain area, North Carolina, USA

Abstract

ABSTRACT The ophiolite of the Buck Creek and Chunky Gal Mountain areas (North Carolina, USA) consist of very high-temperature mafic and ultramafic units. These mafic and ultramafic rocks were once part of the oceanic lithosphere before being subducted and then thrust into continental rock by the Taconic orogeny, which took place during the Paleozoic era. The thrusting of these mafic and ultramafic rocks into nearby metasedimentary rock was controlled by the Chunky Gal thrust fault. Studies on this ophiolite were mainly petrological, geochemical, and structural in nature. The main rocks of interest within this area are dunite, metatroctolite, and amphibolite. The dunite mostly consists of olivine and minor chromite spinels. Hydrous altered dunite may also consist of antigorite, chlorite, talc, and anthophyllite. This dunite is associated with minor scattered lenses of metatroctolite. The metatroctolite is dominated by plagioclase and olivine, which have symplectites and/or coronas of prograde minerals such as pyroxene, spinel, and sapphirine. Some of this metatroctolite was altered via hydration into chlorite schist and edenite-margarite schist, some of which is corundum-bearing. The dunite and metatroctolite are separated from the surrounding metasedimentary units by the surrounding Chunky Gal Amphibolite. This amphibolite, whose protolith is basaltic/gabbroic, is dominated by hornblende and plagioclase.