Long-term effect of inherited basement structures on the basin evolution of northwestern Canada

The Phanerozoic evolution of the Western Canada Sedimentary Basin in the Northwest Territories remains enigmatic due to its scarce stratigraphic record, preventing a complete analysis of passive-margin and retroarc foreland basin deposition. It is unclear how the basin responded to plate-scale tectonic processes such as Neoproterozoic–earliest Paleozoic continental rifting, mid-Paleozoic tectonics, and Mesozoic–Cenozoic Andean-type orogenesis. To investigate how these processes affected the basin, we constrained the thermal evolution of the eastern Great Slave Plain and adjacent Canadian Shield regions by combining stratigraphic cross-section analysis with new and published low-temperature thermochronology and thermal history modeling. We show that maximum heating peaked during the Late Devonian–Mississippian, reflecting sediment burial and enhanced geothermal gradients. Subsequent cooling histories correlate spatially with the erosional edge of the Great Slave Plain. To the east of the erosional edge, the slow Paleozoic–Mesozoic cooling of Precambrian basement rocks is linked to erosion, mantle upwelling, and thermal relaxation. To the west, basement and overlying Phanerozoic strata remained at higher temperatures until rapid cooling started ca. 120 Ma and ca. 60 Ma. These Cretaceous and Cenozoic cooling phases correlate with basinwide sub-Cretaceous and sub-Cenozoic unconformities, respectively, that are documented elsewhere in the Canadian Cordilleran foreland basin and provide new time constraints for the region. We suggest that the different Phanerozoic cooling histories resulted from the reactivation of Precambrian lithospheric structures and the transmission of far-field stresses. Altogether, this study demonstrates the utility of thermochronology to constrain the influence of inherited structures on basin evolution, and to understand how structural heterogeneities govern intraplate tectonic responses to distant tectonic events.