Paper No. 204-7
Presentation Time: 9:00 AM-6:30 PM
BEDROCK GEOLOGIC MAP OF THE CLYDE 7.5-MINUTE QUADRANGLE, WESTERN NORTH CAROLINA, USA
The southern Appalachians record a complex tectonic history associated with the assembly of Pangea following the breakup of Rodinia that included three orogenic events: the Ordovician Taconic, Silurian-Devonian Acadian, and the late Paleozoic Alleghanian orogenies. The northeast-southwest striking dextral Acadian Burnsville fault has been documented from north of Spruce Pine, North Carolina to Asheville, North Carolina and reactivates the Taconic contact between Grenville basement rocks and the Ashe Metamorphic Suite (AMS). This contact extends southwest into the 7.5-minute Clyde quadrangle near Waynesville, North Carolina and transitions into what has been mapped as the northeast-southwest striking Taconic Hayesville thrust fault. The Clyde quadrangle encompasses the intersection of this contact with what has been mapped as the Alleghanian Fries and Chattahoochee thrust faults, and the Taconic Hayesville fault. This study used detailed field mapping of the rocks and structures along with documentation of the kinematics and shear sense indicators along the faults in this quadrangle to address the following: (1) does the Burnsville fault continue into this quadrangle and (2) how are the Burnsville, Hayesville, Chattahoochee, and Fries faults spatially and temporally related? The main findings include: (1) the dextral Burnsville fault extends southwest into the Clyde 7.5-minute quadrangle where it overprints a portion of the Taconic Hayesville fault and (2) the Fries and Chattahoochee faults do not offset the Burnsville fault. These observations suggest that what has previously been mapped in this quadrangle as the Alleghanian Chattahoochee and Fries faults are Taconic structures. During the Taconic, the AMS was thrust over Grenville basement rocks. This complex was thrust over the Cartoogechaye terrane followed by the entire complex being thrust over the Great Smoky Group along the Hayesville fault. Following this, dextral shearing during the Acadian reactivated Taconic structures.