TECTONIC IMPORTANCE OF PALEOZOIC SEQUENCES IN THE SOUTHERN APPALACHIAN WESTERN BLUE RIDGE/TALLADEGA BELT

Stratigraphic correlations within the frontal southern Appalachian metamorphic allochthon (Blue Ridge/Talladega belt) have been hampered by complex structure, a general lack of fossils, metamorphic overprint, and similar lithofacies of different ages. However, the early drift facies Lower Cambrian clastic sequence can be recognized within the western Blue Ridge/Talladega belt in three different structural positions: 1) Along the west flank of the belt (Chilhowee and Kahatchee Mtn. Gps.), 2) In an internal position along both flanks of the Murphy syncline (Nantahala/Brasstown Fms.), and 3) In an intermediate position within the Foothills belt along the overturned west limb of the Copper Hill (Ducktown) anticline (mapped previously as the lower part of the Wilhite Fm. of the Walden Creek Gp. in Ocoee Gorge). In all three of these positions the Lower Cambrian sequence lies stratigraphically above rift-facies rocks of the Ocoee Supergroup. Importantly, in all three settings younger sequences lie stratigraphically (unconformably) above the drift facies units. These include the Talladega and Mineral Bluff Gps., and most of the Wilhite Formation. Paleontological discoveries constrain the age of the Talladega Gp. to be Silurian-Earliest Mississippian, the Mineral Bluff Gp. to be post-Cambrian, and at least part of the Walden Creek Gp. to be perhaps as young as mid-Paleozoic. In addition to stratigraphic position, these three sequences share many aspects of lithofacies in common, including turbiditic and other gravity flow deposits, and a source terrain that included granitic (Grenville) basement and both clastic and carbonate sedimentary cover. These younger units appear to contain the peak metamorphic fabrics contained in the drift-facies and older rocks, and are deformed by the earliest recognized structures in the region.