NSF Award
2418082
The water delivered to the Arctic Ocean by surrounding rivers impacts physical and biological systems in the Arctic and can influence global climate. Understanding the geological history of Arctic rivers provides insights into how the region has evolved over time scales of thousands to millions of years and can help inform future climate models. This research investigates the geoscientific birth and subsequent evolution of the Mackenzie River, the largest river in the North American Arctic. Sedimentary deposits in the Beaufort-Mackenzie Basin record past river patterns and the timing of important regional events. Results from this work will shed new light on the geologic history of the North American Arctic, including the processes that helped shape the region. This investigation will help train multiple Earth Scientists, enhance U.S.-Canadian Arctic research efforts, and improve connections between U.S. researchers and indigenous peoples in the North American Arctic.<br/> <br/>Upper Cenozoic strata in the Beaufort-Mackenzie Basin archive the evolution of high-latitude North American river systems over the last 25 million years, with implications for understanding the drivers behind drainage reorganization and changes to riverine freshwater input to the Arctic Ocean. This investigation will test the hypothesis that re-routing of ancient high-latitude river systems during the late Pliocene led to a pronounced increase in sedimentation rates in the basin. The research will: 1) Decipher the Miocene-Pleistocene sedimentary provenance history of the Beaufort-Mackenzie Basin through detrital zircon U-Pb and Nd-isotope provenance analysis. 2) Establish a chronostratigraphic framework for the sedimentary succession using Sr-isotopes that will constrain the timing of provenance changes and assist in evaluating proposed forcing mechanisms. These datasets will provide insights into when and why sediment and freshwater fluxes to the Beaufort Sea varied during the late Cenozoic, which can be used to inform geologic and paleoclimate models.<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.
