DETAILED GEOLOGIC MAPPING IN THE GREAT BALSAM AND COWEE MOUNTAINS, CENTRAL AND EASTERN BLUE RIDGE, WESTERN NORTH CAROLINA

Detailed geologic mapping of an ~850 km² area between Waynesville and Highlands, NC in the Great Balsam and Cowee Mountains, attempts to resolve fundamental tectonic problems existing between central and eastern Blue Ridge terranes. Near Waynesville, NC the central Blue Ridge consists of the polydeformed, amphibolite facies Cartoogechaye and Dahlonega gold belt terranes. The Cartoogechaye terrane consists of upper amphibolite facies migmatitic biotite gneiss with map- to mesoscale lenses and pods of migmatitic amphibolite. Various ultramafic bodies occur throughout, including the dome-shaped Webster-Addie body. A recumbently folded migmatitic felsic orthogneiss body occurs south of Waynesville possibly representing a small Grenville basement massif. Rocks of the Dahlonega gold belt occur in the footwall of the folded, steeply dipping Soque River fault exposed in small lenticular windows through the Cartoogechaye terrane and in the footwall of the Miss.(?) Chattahoochee fault as part of the larger Great Balsam Mountains (GBM) compound eyelid window. Rocks of the Dahlonega gold belt consist of migmatitic, sillimanite–bearing pelitic schist and metagraywacke with minor mafic and ultramafic bodies. SHRIMP U-Pb ages of metamorphic rims on detrital zircons suggest peak metamorphism in the central Blue Ridge Cartoogechaye terrane and Dahlonega gold belt occurred ~460 Ma, representing part of the Taconic metamorphic core. The roof of the GBM window consists of migmatitic Tallulah Falls Formation metagraywacke, amphibolite, and schist of the Tugaloo terrane (Tt) juxtaposed against central Blue Ridge terranes by the Chattahoochee fault. Evidence for multiple tectonothermal deformation events in the Tt include (1) Taconic (~460 Ma); truncation of folded amphibolite layers by the ~466 Ma Whiteside Granite; (2) Neoacadian (~360 Ma); reported metamorphic rims on zircon; and (3) Alleghanian (~330 Ma); truncation of ~335 Rabun granodiorite, parallelism of magmatic and country rock fabrics, and Ar/Ar cooling ages.