The Canadian Cordillera

Abstract

The physiographic and geologic subdivisions of the Canadian Cordillera are reviewed and the present boundaries between the American, Pacific and Juan de Fuca plates are defined. A preliminary interpretation of the geological history of the Cordillera since the Proterozoic is presented in terms of plate theory. The results of aeromagnetic, magnetic variation, gravity and heat flow measurements, refraction seismic experiments and seismology studies over the Cordilleran region and the adjacent Pacific Ocean arc reviewed and an attempt is made to relate these data to the tectonic history of the Cordillera. Areas of special interest are the present day boundaries between the American, Pacific and Juan de Fuca plates and the recent history of the triple junction between these plates northwest of Vancouver Island. Within the Cordillera interest is focused on the recognition of older plate boundaries and the study of the physical characteristics of the crust and upper mantle.