ANALYSIS OF CONVERGING FAULTS IN THE CORE OF THE CARTERSVILLE RECESS, GEORGIA BLUE RIDGE

One of the largest and most significant structural indentations (Cartersville recess) in the trace of the Appalachian orogen occurs at the latitude of Cartersville, Georgia. This concave cratonward bend in the orogen marks the juncture between the Alabama structural recess and the Tennessee structural salient. The most prominent feature of this juncture is a broad regional antiform that folds the frontal fault system (variably known as the Talladega-Emerson-Cartersville-Great Smokey) of the Blue Ridge/Talladega belt metamorphic allochthon. The western Blue Ridge narrows southwestward into this bend and strikes into the Talladega belt, which in turn expands in outcrop width and thickness farther to the southwest. Several regional fault systems also converge on this narrow constriction, including the frontal fault of the Blue Ridge allochthon, the eastern/western Blue Ridge boundary (Allatoona fault), and at least one internal western Blue Ridge fault. The regional strike of the Allatoona fault in the Acworth and Burnt Hickory Ridge quads is approximately N 57 E. It maintains a relatively straight trace for >110 km across the Cartersville recess and forms the boundary between the Talladega belt/western Blue Ridge and possibly exotic terranes of the eastern Blue Ridge to the southeast. The internal western Blue Ridge fault, the Allatoona Pass fault (APF), is a dextral strike-slip fault trending N 65 E, 50 SE. This fault crops out along the shores of Allatoona Lake northwest of the Allatoona Battlefield at about 34° 7' latitude 84° 43' 45" longitude. Seventeen S-C measurements taken from the fault zone yield a well-constrained slip vector of 10, N 75 E. Slip on this fault appears minor, as evidenced by the presence of Pinelog Formation on both sides of the westward projection of the APF. The APF lies within the inner arc of the southern limb of the southwest plunging antiform marking the Cartersville recess. Origin of the APF may be linked to compression within the inner arc of this antiform as a compensation structure, and this model accords with the APF's limited lateral extent and dextral slip.