Physical Sciences and Mathematics Commons^™

Quantifying The Magnitude And Spatial Variability Of Bedrock Erosion Beneath The Sisters Glacier, Washington, Using Cosmogenic 3he Concentrations, Sarah W. Francis

WWU Graduate School Collection

Cosmogenic ³He analyses provide a tool to infer spatial variation of cirque-glacial bedrock erosion. ³He accumulates in bedrock exposed at the surface as a result of cosmic ray bombardment; the concentration of cosmogenic ³He increases with exposure time as well as proximity to the surface. The Twin Sisters range, North Cascades, WA is an ideal location to use cosmogenic ³He to infer cirque-glacial erosion depths and rates, due to the dunite bedrock and the detailed record of Holocene glaciation from the nearby Mount Baker. We used field mapping, lidar data and aerial imagery to identify bedrock …