3-D DEPOSITIONAL AND STRUCTURAL EVOLUTION OF THE WESTERN BLUE RIDGE: IMPLICATIONS FOR PRE-OROGENIC BASEMENT AND COVER GEOMETRY CONTROLLING MAJOR PALEOZOIC FAULTING

The polydeformational history of the western Blue Ridge (WBR) and its primary lithostratigraphic unit, the Ocoee Supergroup (OSG), in conjunction with the interpreted complexity of the original rift setting, has made the present day structural and stratigraphic relationships difficult to unravel. Regional synthesis of detailed mapping and geochronology and construction of new 3-D models which incorporate critical relationships observed in selected regions (SW of Great Smoky Mountains, western Great Smoky Mountains, Webb Mountain-Big Ridge, Ravensford anticline, Hot Springs window) allow many poorly understood OSG depositional and structural characteristics to be unravelled. Terranes such as the WBR are often poorly understood because stratigraphy and structural features reveal significant variation both across and along orogenic strike. Thus, deciphering the origins of the present day deformation can often present great difficulty unless a 3-D approach is utilized. Construction of 3-D models involved a minimum six step retrodeformation of present deformed state sections based on the most recent detailed work in most parts of the WBR. Multiple datasets (field relationships, geochronology, etc.) were utilized to establish the sequence of deformation followed during reconstruction of the OSG basin. New interpretations suggest that the Greenbrier (GBF), Rabbit Creek (RCF), and Dunn Creek (DCF) faults, though possibly kinematically linked, are not manifestations of the same structure. Characteristic stratigraphy in each respective thrust sheet and involvement of basement rocks and their associated OSG cover may indicate that the pre-Paleozoic OSG basin geometry attributed to heterogenous Rodinian rifting is strongly related to the evolution of major early faults such as the GBF, RCF, and DCF.