THE CAROLINA MISSISSIPPI FAULT AND POSSIBLE IMPLICATIONS FOR PANGEA RECONSTRUCTION MODELS

Discovery of the Intra-Pangean Paleomagnetic (IPP) anomaly led to decades of debate over Pangea reconstruction with multiple models being proposed (most notably Pangea A, A1, A2, B, and C). Alternates to the traditional Pangea A model were constructed to account for the seeming overlap of Gondwana and Laurasia evidenced by paleomagnetic data for the late Paleozoic. Attempts of explaining the IPP as due to inclination shallowing and/or magnetic overprints along with a lack of evidence for the supposed “Pangean Megashear” required by the other models (Pangea B), has led to a long-lived Pangea A theory being more widely accepted. However, in recent years the Pangea B model has continually received interest based on supporting evidence in the European Varsican Orogeny.

It has long been known that crust of both Gondwana and Laurentian origin are found in the Southeastern United States. While the exact relations between the two remain difficult to determine, recent seismic and magnetic work has brought renewed interest to the Carolina-Mississippi Fault (CMF) concept. This supposed feature at the southern end of the Appalachians cross cuts all known terranes and structures of the mountain chain and its geometry implies a large dextral shear component. The presence of a large dextral transcurrent fault in this region has been proposed in the Pangea B reconstruction, as part of the “Pangean Megashear” system that was active in the late Paleozoic. Accordingly, the CMF may provide evidence for a Pangea B model.