Document Type



Faults in the Virginia Blue Ridge province typically are reverse/thrust faults that place older rocks over younger rocks, a result of tectonic collision and crustal shortening in the Paleozoic. In the Sherando Quadrangle in central Virginia, the ENE-WSW striking, 5-km long Little Stony Creek fault (LSCF) displaces younger rocks of the Swift Run and Catoctin formation downward, in contact with older Mesoproterozoic granitic basement rocks. Detailed field mapping, cross-section restoration, and petrographic analysis reveals mylonitic textures occur in basement rocks along the Little Stony Creek fault, extensive asymmetrical folding of the cover sequence, and the preservation of normal slip kinematics. Mylonitic basement rocks are localized along the fault and are subparallel to the orientation of the Little Stony Creek fault, indicating that preserved extensional kinematics are not a result of Mesozoic Atlantic rifting. We posit that Ediacaran deposition of cover rocks was coeval with original normal faulting. During later Paleozoic contraction, fault orientation and differential lithology limited reactivation slip. Regional shortening of the cover sequence and deformation of local basement accommodated contraction. The basement complex acted as a backstop or rigid buttress across the LSCF against which the cover sequence developed asymmetrical folds.

Date Awarded

Spring 2021



Advisor 1

Chuck Bailey