CRUST AND UPPER MANTLE STRUCTURE BENEATH THE NORTHERN AND SOUTHERN APPALACHIANS

An emerging conceptual framework for the tectonic evolution of the Appalachian orogen posits that from the Mesoproterozoic to at least the Permian the tectonic evolution of the northern and southern segments of the Appalachians was different, and that the boundary between these segments is coincident with the New York Promontory and the Pennsylvania Embayment. It has been further hypothesized that variations in lithospheric structure could be the root cause of the contrasting north vs. south tectonic histories of the orogen. Published geophysical models of crust and upper mantle structure beneath eastern North America will be reviewed to evaluate this model for the Appalachian orogen.