LITHOSPHERIC PROFILES ACROSS THE APPALACHIAN MOUNTAINS

The present day U.S. Appalachian Mountains occupy a region that has evolved through several Paleozoic orogenic events from its beginning as a rifted and passive margin after the Precambrian Grenville orogeny. The Alleghanian orogeny marked the final orogenic event during the Late Carboniferous-Permian and completed the construction of Pangea. During the Triassic, Pangea began breaking apart and its presence is shown in the eastern U.S. by a series of nonmarine clastic-filled rift basins that parallel the Appalachian Mountains. The strength and nature of all of the above these tectonic events greatly influenced the overall lithospheric structure in the eastern U.S. as illustrated by geologic mapping and geophysical studies. Additionally, the amount of tectonic deformation varies along the strike of the Appalachian Mountains. In order to study these variations and the nature of the lithosphere in the eastern U.S., we compiled gravity and aeromagnetic data, and constructed four lithospheric scale models that will be shown as gravity models but are constrained by available geological, seismic and drill hole data. In addition, we constructed a series of wavelength filtered and horizontal derivative gravity and magnetic anomaly maps that will be used in conjunction with the gravity models in order to determine the general lithospheric structure of the region. These models are intended to aid future studies of the lithosphere in the eastern U.S. including the upcoming U.S. Array experiment.