Collaborative Research: A place-based, student-led research project in the Pioneer Mountains, Montana: an investigation of very dry, alpine glaciation proximal to the Laurentide Ic

The University Of Montana-Western, Dillon MT

Investigators

Abstract

This project will incorporate local geoscience students and an experiential, place-based educational approach to reconstruct the glacial history of the Pioneer Mountains in southwest Montana. This project will immerse first-generation, under-represented college students at the University of Montana Western in climate research. Students will investigate the region’s glacial history in collaboration with the NSF-supported Community Cosmogenic Facility at University of Vermont. The investigators will test the hypothesis that glaciers, located near large ice sheets and experience both cold temperatures and exceptionally low precipitation, may have reached local ice extent maximums considerably earlier than the Laurentide (i.e., Canadian) Ice Sheet maximum (~21,000 years ago). They will do this by sampling and dating glacier moraines in the Pioneer Mountains, which today have very low precipitation due to blocking by ranges along the Continental Divide. Glacier moraine sequences from the Pioneer Mountains may shed new understanding into the mechanisms by which mountain glaciers respond to Earth’s long-term orbital fluctuations and concomitant climatic changes. This place-based research project will provide the undergraduate students, many of whom are from rural Montana, with an immersive opportunity to better understand their own states’ landscapes, the geomorphic processes that formed them, and the important climatic information they provide. This research will provide insight into glacier advance and retreat during the last glaciation in continental climatic regions that were proximal to the Laurentide Ice Sheet (LIS), in an exceptionally dry mountain range where the glacial chronology has not been studied. The Pioneer Mountains are one of the few ranges in western Montana underlain by granite, making it feasible to use 10Be in quartz for cosmogenic nuclide exposure ages and thus produce the first moraine chronologies for the region. The investigators will test whether the differences in maximum-ice times found in eastern ID and northwestern WY are due to regional climatic contrasts, such as anticyclonic wind patterns driven by the presence of the LIS or non-climatic factors (e.g., hypsometry and response time). Such atmospheric pressure systems would deflect westerly maritime moisture flux away from the northern Rocky Mountains as the LIS developed, and therefore the glacier maxima in the Pioneers may precede the LIS maxima and the aforementioned glacier systems. Results from this work will advance the understanding of temperature-dependent glaciers under extremely dry and very cold conditions, providing insight about how current glaciers in the coldest, driest regions of the world may respond to modern climate warming. This project is jointly funded by the Geomorphology and Land-use Dynamics Program (GLD) and the Established Program to Stimulate Competitive Research (EPSCoR). 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.