GEOLOGIC MAP OF MOST OF THE BLUE RIDGE AND PIEDMONT IN GEORGIA AND PART OF THE MURPHY STRUCTURE IN NORTH CAROLINA

Georgia, the largest state east of the Mississippi River, contains a complete section across the Appalachian Mountain system, from the Cumberland Plateau province in its northwestern corner, through the Valley and Ridge, Blue Ridge, and Piedmont provinces and the Carolina superterrane (fig. 1); most of the provinces have at least one subprovince. East of the inner Piedmont in eastern Georgia is a large area underlain by the Carolina superterrane that consists of mildly metamorphosed volcanic and plutonic rocks of Cambrian and Cambrian? rocks

A significant feature of the Blue Ridge in Georgia and southernmost North Carolina is the Murphy structure (“Murphy Syncline of many previous workers”) that our mapping shows is probably not a syncline, but a complex structural/stratigraphic feature that locally has Appalachian basement (ca 1.1 billion old) in it’s core as well as younger Paleozoic rocks. Another significant feature is the Dog River Window, adjacent to the Brevard zone in the Blue Ridge in western Georgia and northeastern Alabama, where garnet-grade metasedimentary rocks of the Emuckfaw Formation are overlain in structural contact by much higher-grade rocks in the Allatoona allochthon. The map covers part or all of the Blue Ridge in the Dalton, Toccoa, Cartersville, Anniston, Commerce, Atlanta, and La Grange 30 x 60 minute quadrangles and the Piedmont in the Thomaston, Macon, Griffin, Milledgeville, Athens, Atlanta, and Commerce 30 x 60 minute quadrangles.