New Interpretation of Cretaceous Basin Development, Orogenesis, and Tectonism In the Cordillera (U.S. and Canada) Based on Reconstruction of Major Cretaceous-Cenozoic Strike-Slip Faults

Numerous recent studies have emphasized the importance of Cretaceous-Cenozoic strike-slip fault restoration for paleogeographic and paleotectonic reconstructions of the Cretaceous and older North American Cordillera. Offsets of 100's of km, mostly in a dextral sense, are indicated by geologic relations for numerous individual fault systems in the Canadian and U.S. Cordillera, starting in the Early Cretaceous and continuing in places to the present. When known fault offsets are restored, the distribution of Cretaceous and older provinces of the Cordillera (sedimentary basins, magmatic and orogenic belts) is very different from today. For example, the metamorphic core of the southern Coast Orogen (BC and WA) restores to a position adjacent to the coeval metamorphic welt of the western Idaho shear zone and the coeval Ochoco-Hornbrook sedimentary basins, and the Great Valley forearc basin of California restores to a position west of the Peninsular Ranges batholith (Mexico). In this talk, I will use base maps and reconstructions of Wyld et al. (2001, 2006) and Wright and Wyld (2007), along with new modifications, as a platform for revised analysis of how Cretaceous sedimentary basins of the U.S. and Canada Cordillera, from the foreland to the forearc, relate to Cretaceous orogenic belts and tectonic processes. The analysis has implications for interpretation of time-space variation in the evolution of basins and orogenic belts, driving forces of sedimentary basin development, sediment provenance, terrane linkages, and tectonic models. It also highlights promising new areas for future research.