PROBLEMATIC CORRELATIONS IN THE FRONTAL METAMORPHIC ALLOCHTHON OF THE SOUTHERN APPALACHIANS: STRUCTURAL AND STRATIGRAPHIC SOLUTIONS

The frontal metamorphic allochthon in the southern Appalachian orogen contains thick cover sequences ranging in age from the rift-associated late Proterozoic Ocoee Supergroup (OS) (>12 km thick) in the southern Blue Ridge (BR) of north Georgia to the middle Paleozoic (Devonian-Mississippian (?)) Talladega Group (TG) successor basin sequence (>3 km thick) in the Talladega belt (TB) in central Alabama. The part of the allochthon between the well established late Proterozoic sequences in the Georgia BR and the Paleozoic sequences in the Alabama TB to the SW is an enigmatic sequence of thick, homogeneous turbiditic rocks generally lacking facing data or easily differentiated internal units. Both the lower (Talladega-Cartersville-Great Smoky fault) and overlying (Hollins Line-Allatoona) boundary faults of the allochthon cut obliquely through these sequences, both along and across strike, and the sequence in question narrows to ~1 km in thickness as these faults approach each other in the hinge of the Cartersville structural recess. Because some units within both the TG and OS are lithologically very similar to the sequence in question, detailed geologic mapping is required to merge the stratigraphy established within the BR with that along strike in the TB. Regional unconformities within both the BR and TB place younger Paleozoic units against the Lower Cambrian Chilhowee Gp. These unconformities may cut entirely through the Chilhowee Gp. in the region under study, juxtaposing the two turbiditic sequences (OS and TG) mentioned above, and placing the Silurian (?)- Devonian Lay Dam fm. of the TG against units of the Great Smoky Gp. of the OS.