Paleomagnetism and 40Ar/39Ar ages from the Carolina slate belt, Albemarle, North Carolina: Implications for terrane amalgamation with North America

Abstract

Paleomagnetic and /sup 40/Ar//sup 39/Ar dating studies of Late Proterozoic metamorphic rocks from the Carolina slate belt were undertaken to gain insight into the history of this suspect lithostratigraphic terrane. Geochronological data suggest a peak metamorphic age of ca. 455 Ma and a later thermal overprint at ca. 185 Ma. Thermal demagnetization indicates two magnetization components. A low-temperature component yields a pole close to 180-190 Ma segments of the North American apparent polar wander path. A high-temperature component postdates folding and is inferred to have been acquired at ca. 455 Ma (corresponding paleomagnetic pole is lat 20/sup 0/N, long 80/sup 0/E). Although paleomagnetic data from the Carolina slate belt remain too ambiguous for construction of a unique polar wander path, consideration of available paleolatitudes suggests that the terrane may have been proximal to cratonic North America after ca. 455 Ma. This result contrasts markedly with high southerly Ordovician paleolatitudes inferred from paleomagnetic studies within central and northern Appalachian terranes.