Thermochronologic and Geophysical Investigations of Canadian Cordilleran Crust

Abstract

Lithospheric-scale geodynamic processes are interconnected with surface processes such as erosion and tectonic denudation, therefore the integration of geological and geophysical data is valuable when developing geodynamic models. One geodynamic problem that has gained worldwide interest is the contrast in lithospheric properties between the hot and thin Canadian Cordillera and cold and thick North American craton. This thesis focuses on characterizing two aspects of the crust in western Canada: 1) ancient surface and near-surface processes using low-temperature (U-Th)/He thermochronology; and 2) modern geothermal gradients using a wavelet analysis of magnetic anomalies. The first study resolves a differential, tectonically-driven Cretaceous exhumation history in the northern Canadian Cordillera. The second study finds that Curie depths (~580 °C) are shallow throughout the Cordillera, averaging ~15 km, compared to the Canadian Shield, averaging ~33 km. Both studies provide useful constraints for modeling the geodynamic evolution of the Canadian Cordillera.