POLYPHASE FOLDING IN THE SIX MILE THRUST SHEET (INNER PIEDMONT), TAYLORS QUADRANGLE, GREENVILLE COUNTY, SOUTH CAROLINA

During geologic mapping of the Taylors 7.5-minute quadrangle, six distinct fold phases were recognized at the mesoscopic and map scales. These phases were differentiated using fold morphologies, fold orientations, and refolded relationships. Four mesoscopic fold phases were recognized. From oldest to youngest they are: intrafolial, isoclinal folds of compositional layering (possibly refolded); tight to isoclinal, upright to recumbent folds of the main foliation (MF); open folds of MF plunging gently to the east; and a second open fold set that refolds the others with a more northerly trend. Two map-scale folds subsequently refold all the previous mesoscopic fold phases.

The early isoclines are sparse and are herein named Suber Mills (SM) for the locality where they were first described. Chevron and isoclinal folds with symmetric to asymmetric forms occur; they are best observed in unsheared, laminated mica schist and are herein named Pebble Creek (PC). A shearing fabric (SF) affects both of these early fold phases by reorienting earlier s-surfaces of SM and PC folds, and by forming c-surfaces. The MF and SF were folded into open, eastward plunging folds, herein named Enoree (ER) for outcrops first noted along the northern reaches of the Enoree River. The final mesoscopic fold phase cross folds the ER at nearly right angles with a northerly trend. These open folds are named Wade Hampton (WH) for exposures noted in an excavation pit. The interference pattern between ER and WH commonly gives rise to basin and domes in pavement outcrops.

The Taylors synform is a macroscopic structure located in the center of the quadrangle. It is based on a map pattern that refolds WH fold axes and plunges gently to the east. A second map-scale fold, the Greer system, refolds the Taylors synform about a north-northeast axis, and it is the last recognized phase of folding. Both of these structures correlate with structures mapped to the east by Bramlett and Griffin (1978).