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...