This thesis presents geochronological, structural and geophysical evidence of the complex tectonic history of northeastern North America in a geologic window from the Permian to Recent times, spanning the beginning of rifting of supercontinent Pangea until the current passive margin stage. 40Ar/39Ar geochronology on mafic and felsic sheet intrusions from New England suggests a high sensitivity of the method to a fine crystalline texture, excess argon from Paleozoic crustal rocks, and argon loss from subsequent thermal events. Before the widely recognized ~201 Ma Central Atlantic Magmatic Province, magmatic events occurred at ~271 Ma, ~247 Ma and ~220 Ma. The combination of these and previously published ages with structural data of sheet intrusions and faults allowed dating and characterization of the stress/strain state that resulted from the interaction of magmatism and crustal deformation. Consequently, the data suggest a shift from NW-SE extension before and during rifting, to NE-SW extension and strike-slip regimes after rifting. Seismic-reflection data, well-log data and recent seismic activity provide evidence of such late deformation; however, channel fills of glacial origin could create artifacts in the geophysical data that obscure the true deformation.
|Advisor:||Withjack, Martha O., Schlische, Roy W.|
|Commitee:||Mountain, Gregory E., Turin, Brent D., Gazel, Esteban|
|School:||Rutgers The State University of New Jersey, School of Graduate Studies|
|School Location:||United States -- New Jersey|
|Source:||DAI-B 81/7(E), Dissertation Abstracts International|
|Subjects:||Geology, Plate Tectonics|
|Keywords:||Argon, Deformation, Geochronology, New England, Nova Scotia, Seismic reflection|
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