NSF Award
2419297
Sedimentary basins adjacent to convergent margin mountain belts host important economic resources and contain key records of past climatic and tectonic events. As such, basin archives are often used to reconstruct long-term variability in mountain building and climatic processes. New quantitative approaches provide direct links between signals of erosion in mountain belts and depositional processes preserved in basins, which can improve understanding of how to interpret these critical sedimentary archives. This project applies novel methodologies to the Alberta basin, next to the Canadian Rocky Mountains, which provides an excellent testing ground due to abundant subsurface datasets and constraints on the geometries of deformation within the mountain belt. This grant supports training of undergraduate and graduate students, collaborations between US and Canadian geoscientists, and development of training modules for the technical methods utilized in this proposal which will be made publicly available to other researchers.<br/><br/>This project couples bedrock low-temperature thermochronology and thermokinematic modeling within the fold-thrust belt, with detrital thermochronology, subsidence curves, and provenance analysis in the foreland basin to assess linkages between fold-thrust belt shortening in the Canadian Rocky Mountains and depositional pulses in the Alberta foreland basin system. Low-temperature thermochronology (zircon fission-track and zircon (U-Th)/He), applied in an orogen-perpendicular sampling transect across major thrust sheets, will constrain the timing and pathways of rock cooling. In the foreland basin, stratigraphic sections and maximum depositional ages from detrital zircon geochronology will facilitate construction of sediment accumulation curves. Detrital zircons dated for U-Pb geochronology will also be dated via low temperature thermochronology, which will allow calculation of lag times. Ultimately, constraints from the fold-thrust belt and subsidence histories from the foreland basin will be combined in a flexurally validated, thermokinematic model, which will provide sequential, temporally constrained reconstructions of shortening magnitude, thrust belt geometry, and size and location of the orogenic load. These datasets will resolve: (1) the timing and magnitude of shortening, and whether it was a protracted or pulsed process, and (2) the relationships between thrust loading, unconformity development, and coarse clastic deposition.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
