The geologic transition between the western Blue Ridge and eastern Piedmont provinces in Central Virginia is a complex and poorly understood boundary that has recorded the many deformational events that have occurred along southeastern Laurentian (North American) continental margins. One group within this transitional area is the Evington Group which is composed of metasedimentary phyllites, schists, quartzites, marbles, and greenstones likely Cambrian in age originally deposited within the Iapetus Ocean along Laurentian continental margins. Stratigraphic units within the transition have been interpreted as either Evington Group rocks or a repeated sequence of Lynchburg Groups rocks by a SE-NW striking thrust fault. The two opposing models for this transition are the Bowens Creek fault model (BCF) which proposes a regional-scale thrust sheet and the Buckmarlson Transition Zone model (BTZ) which proposes a 3-5 km wide “transition zone” of various strain within Evington Group rocks. We sampled quartzite and schist at outcrops following the SE-NW strike of the Bowens Creek Fault for analysis of strain, bedding and foliation, and quartz recrystallization states. Strain analysis of two samples indicate dextral to oblique dextral shear paralleling the SE-NW strike of the BCF contradicting the kinematics of the fault. Quartz recrystallization states observable in thin section range from low to high with varying deformation and varying strike and dip of foliation and bedding measurements. The lack of structural, deformation, and strain evidence supporting the kinematics and location of the BCF implies that area is more accurately represented by the BTZ model.
Christopher M. Bailey
Pearson, Olivia, "Kinematic and vorticity analysis of quartzite from the Evington Group, eastern Blue Ridge, Virginia" (2021). Geology Senior Theses. William & Mary. Paper 9.