EXAMINING LINKS ACROSS THE CENTRAL AND SOUTHEASTERN CANADIAN CORDILLERA FOR A UNIFIED SYNTHESIS OF JURASSIC–CRETACEOUS TECTONIC EVOLUTION

Restoration of tectonic elements in the interior of the Canadian Cordillera (central Intermontane Belt) to their paleogeographic position in the Mesozoic permits comparison of data from western and eastern sides of the Cordillera, and recognition of the interplay between coeval lithospheric thickening and basin evolution across the orogen. This provides constraints for a new model of Mesozoic tectonic evolution for the southern Canadian Cordillera.

Onset of coarse clastic Intermontane Belt sedimentation in the Bowser Basin in the Middle Jurassic occurred in response to terrane accretion events preserved in the Omineca Belt. Coeval Late Jurassic and Early Cretaceous sedimentation in the Bowser Basin and the Alberta Foreland Basin farther east, was influenced by lithospheric loading resulting from progressive crustal shortening and northeastward translation of thickened crust and an Omineca Belt highland between the two basins, onto the North American Craton. Provenance of detritus in these basins, and in the Late Cretaceous nonmarine clastic Sustut Basin (central Intermontane Belt), reveals drainage migration patterns in the intervening Omineca Belt highland throughout the Late Jurassic and Cretaceous. The presence of synchronous and compatible tectonic events in the adjacent central Intermontane Belt and southern Omineca and Foreland belts suggests that they were kinematically connected above a lower crustal detachment beginning in the Middle Jurassic. Similar relationships suggest that from mid-Cretaceous to Early Cenozoic, the Coast Belt was part of this dynamically linked accretionary orogen, and the lower crust detachment rooted near the active plate margin and passed beneath the Coast, Intermontane, Omineca, and Foreland belts.