GEOLOGIC MAP OF THE SOUTHERNMOST APPALACHIANS OF ALABAMA AND GEORGIA: A SYNTHESIS OF RECENT ADVANCES IN MAPPING, GEOCHEMISTRY, GEOCHRONOLOGY, AND TECTONIC INTERPRETATION

The southernmost Appalachians of Alabama and Georgia consist of rocks which record a full Wilson cycle – from the Neoproterozoic (ca. 570 Ma) breakup of the Rodinian supercontinent through the latest Paleozoic (ca. 300 Ma) amalgamation of Pangea. The map presented here compiles the best published and unpublished work from a myriad of workers in this section of the orogenic belt. In addition, we synthesize lithologic, geochemical, and geochronologic information into a coherent tectonic framework that accommodates the comprehensive dataset presented. The map focuses on units that record the breakup of Rodinia and evolution of the Neoproterozoic to Lower Ordovician passive margin of Laurentia (foreland, Talladega belt-western Blue Ridge, eastern Blue Ridge, Pine Mountain belt) and overlying Taconic, “Sea of Japan-style” back-arc basin (Wedowee-Emuckfaw-Dahlonega back-arc basin), as well as a corresponding Iapetus-facing Ordovician arc terrane (Dadeville Complex) on the seaward margin of the Laurentian-plate. The map, additionally, includes middle to upper Paleozoic, Laurentian shelf units (foreland, Talladega belt-western Blue Ridge) that developed inboard of an evolving Acadian to Alleghanian orogenic belt which deformed the older passive margin, back-arc and arc lithologies, resulted in voluminous silicic magmatism (eastern Blue Ridge) and peak dynamothermal metamorphism, and telescoped Laurentian (foreland, Talladega belt, western Blue Ridge, eastern Blue Ridge, Opelika Complex, Dadeville Complex, Pine Mountain belt) and exotic (Uchee belt, Carolina terrane) lithotectonic terranes across younger faults (e.g. Hollins Line, Allatoona fault, Abanda fault, Stonewall Line, Towaliga fault). Using modern geochronology and other age relationships, we also present a series of tectonic “time slices” depicting the Neoproterozoic to latest Paleozoic evolution of the Laurentian margin in this segment of the Appalachian orogenic belt.