A new tectonic map of the southern and central Appalachians incorporates modern field and structural-stratigraphic, geochronologic (mostly sensitive high-resolution ion microprobe–reverse geometry, SHRIMP–RG, and Sm-Nd), geochemical, and geophysical data to identify crustal boundaries and blocks. Major tectonic units include the ∼735 Ma Laurentian failed rift, ∼565 Ma rifted margin sedimentary-volcanic assemblage deposited on Grenvillian and pre-Grenvillian crust, the Laurentian platform, and a series of distal Laurentian terranes (Cowrock, Cartoogechaye, Tugaloo-Chopawamsic-Potomac) accreted to Laurentia during the Taconian (Ordovician) or Neoacadian (Late Devonian–early Mississippian) orogenies. The Dahlonega gold belt consists of more proximal metasandstone and pelitic schist; it also contains Ordovician arc volcanic rocks, and a mixed detrital zircon suite of Laurentian and Gondwanan, or Penokean, affinity. The newly recognized Cat Square terrane contains Laurentian, Avalonian, and 430 Ma detrital zircons, and is considered a remnant ocean basin that closed during Acadian-Neoacadian accretion of the Carolina superterrane. The Pine Mountain terrane (southernmost exposed Appalachians) consists of Grenvillian basement and a cover sequence bearing Gondwanan or Penokean detrital zircons. The Carolina superterrane contains numerous peri-Gondwanan terranes that were deformed, metamorphosed, and amalgamated prior to 530 Ma, then accreted to Laurentia during the Neoacadian along the central Piedmont suture. The Raleigh-Goochland terrane contains blocks of Laurentian basement and cover that moved SW (dextrally) out of the collision zone to the north as the Theic ocean closed north to south during the early Alleghanian orogeny. This event also produced the Kiokee-Raleigh belt high-grade metamorphic core in the eastern Piedmont, and includes faults of the Pine Mountain window. The latter is framed by Alleghanian thrust and dextral faults formed at different crustal depths (times?). Subsurface components of the southern and central Appalachians are recognized in potential field and limited drill data. The Carolina superterrane extends beneath the Coastal Plain—possibly eastward to the East Coast magnetic anomaly. South of the Carolina superterrane and north of the Wiggins suture is the Brunswick (Charleston) terrane, another peri-Gondwanan terrane. The east–west Alleghanian Wiggins suture with the Suwannee terrane is recognizable to the south beneath Georgia and Alabama in potential field data, truncating all Appalachian structures and older crustal blocks west of the Appalachians. South of the suture, African basement and cover lie in the eastern Florida subsurface, while to the west are other Gondwanan or peri-Gondwanan components that may have originally connected with Yucatan.

A late Paleozoic fault duplex forms a structural culmination in the Blue Ridge-Piedmont thrust plate near Cartersville, Georgia. The duplex contains at least three major lens-shaped horses, stacked vertically and bounded by faults that branch from the sole of the Blue Ridge-Piedmont plate. The duplex telescopes older Paleozoic structures and metamorphic fabrics that are related to Taconic thrusting of the Blue Ridge over the North American shelf. The duplex, embedded in the sole of the Blue Ridge-Piedmont plate, may have been detached from the area of the Pine Mountain window in the central Georgia Piedmont, and horizontally displaced 130 km during formation of the Valley and Ridge fold and thrust belt.

Thrusts in the crystalline core of the southern Appalachians formed by both ductile and brittle mechanisms during three or more major Paleozoic deformational-thermal events (Taconic, Acadian, Alleghanian), in contrast to thrusts in the foreland which formed primarily as brittle faults during the Alleghanian. Early prethermal peak thrusts formed in the crystalline core, then were subsequently thermally overprinted and annealed. Thrusts that formed late in a metamorphic-deformational sequence have maintained a planar geometry. Many of these thrusts, such as the Brevard and Towaliga faults, were later reactivated in either the ductile or brittle or both realms, possibly involving both dip-slip and strike-slip motion. The thrusts framing the Pine Mountain and Sauratown Mountains windows formed both pre- and post-thermal peak. The pre-thermal peak Box Ankle thrust in the Pine Mountain window is a structurally lower fault, whereas the window is flanked externally by the post-thermal peak Towaliga (northwest) and Goat Rock (southeast) faults. Conversely, in the Sauratown Mountains the brittle Hanging Rock thrust frames an inner window beneath the older Forbush thrust. Here a downward and outward propagating sequence is suggested for the development of thrusts. North American basement rocks are involved in both the Pine Mountain and Sauratown Mountains windows, and basement and cover behave as a homogeneously coupled mass with respect to strain. Consequently, the only factor that controlled the siting of early thrusts may have been the depth to the ductile-brittle transition zone. The frontal Blue Ridge thrust was the last formed in the Blue Ridge-Piedmont thrust sheet although the Cartersville-Miller Cove thrust is a slightly older Alleghanian thrust than the Great Smoky fault.