GAYDEN'S CREEK DUCTILE DETACHMENT FAULT, FLINT HILL, SC

A 1.5-5 km wide slice of Carolina terrane greenschist facies metavolcanic rocks northeast of Winnsboro, SC, is bounded to the north by a steeply north-dipping fault against Charlotte terrane granitic gneisses. To the south of the slice, the Gayden's Creek fault (GCf) separates the metavolcanic rocks from the Silverstreet portion of the Charlotte terrane rocks that include gneiss, amphibolite, mica schist, metaplutonic rocks, and pegmatites. The GCf terminates to the east at the younger Liberty Hill granite, and on the west, it intersects the Beaver Creek dextral shear zone. Although a zone of shearing and mylonitic rocks lies in a zone up to 800 m. wide both to the north and south, the GCf is a discrete surface that strikes N70W to N70E and dips 30 to 60 degrees to the north. Mineral lineations on the shear planes that are parallel to the fault plunge 20-45 degrees toward the northeast. Asymmetric porphyroclasts, S-C fabric, C-C' fabric, and microfolds all indicate that the metavolcanic block is down to the north. The fault has the appearance of a right normal fault and lies on the north limb of the Flint Hill anticlinorium, a regional fold that affects both the Carolina terrane and the Charlotte terrane. If the fault predates the anticlinorium, it could be a folded thrust. If it was co-genetic or post-dates the anticlinorium, it is a low-angle normal detachment fault. The latter explanation would explain the metamorphic rock grades since the normal fault would allow excision of the metamorphic rocks between the higher grade gneisses and the lower-grade metavolcanics. The setting and characteristics of the GCf are similar to the Alleghanian right-normal Towaliga and Goat Rock faults in Alabama, and the extensional Augusta and Modoc fault zones in South Carolina.