U-Pb dating of granites from the Charlotte belt of the southern Appalachians

Abstract

New U-Pb zircon ages from plutons in the Charlotte belt of the southern Appalachians have provided evidence of Cambro-Ordovician and Siluro-Devonian magmatic activity. Several U-Pb zircon ages of Cambro-Ordovician plutons predate their Rb-Sr whole rock ages by as much as 60 m.y., suggesting a post emplacement disturbance of the Rb-Sr isotopic systems. Comparison of geologic setting, chemistry, and temporal and spatial distribution of Charlotte belt Siluro-Devonian plutons with those of other tectonic environments, specifically plutons from tensional environments, suggests a model for strike-slip accretion.