Southwest extension of dextral transpression along the Burnsville fault into the Clyde 7.5-minute quadrangle, western North Carolina, USA

Abstract

The Neoacadian Burnsville fault is a dextral transpressional structure exposed in western North Carolina. Bedrock geologic mapping in the Clyde 7.5-minute quadrangle documents the fault an additional ∼40 km southwest than previously mapped. Here it overprints the contact between the Ashe Metamorphic Suite (AMS) and Grenville basement and a portion of the Hayesville fault, both older Taconic structures. Neoacadian deformation was partitioned onto these pre-existing structures. The Burnsville fault intersects faults previously interpreted as the younger Alleghanian Fries and Chattahoochee faults. These do not offset the Burnsville fault here suggesting that they are Taconic and not the Fries and Chattahoochee faults. Our results suggest: (1) Grenville basement was thrust over the Cartoogechaye terrane, (2) the AMS was thrust over both by the Holland Mountain thrust, (3) all were then thrust over the Great Smoky Group by the Hayesville fault, and (4) these structures were later overprinted by Neoacadian dextral shear.

Keywords

• burnsville fault
• strike-slip fault
• neoacadian orogeny
• southern appalachians
• bedrock geologic map
• blue ridge