SURFICIAL GEOLOGIC MAPPING OF TWO PARTIAL AND TWO COMPLETE 7.5-MINUTE QUADRANGLES AND PRODUCTION OF A GLACIAL GEOLOGIC MAP OF THE TAYLOR VALLEY, COLORADO

The Taylor River Drainage, located within the Southern Sawatch Range, was extensively glaciated during the last Pleistocene glaciation. Snow and ice accumulation in high-altitude cirques and upland ice fields fed large valley glaciers in the Taylor River and Spring Creek drainages. This EDMAP-supported project expands upon decades of research to map, model, and date the culmination and retreat of the Taylor River Glacier Complex (TRGC) during the last Pleistocene glaciation. The resultant surficial geologic map encompasses the Pieplant and Italian Creek 7.5’ quadrangles and northern portions of the Matchless Mountain and Taylor Park Reservoir 7.5’ quadrangles. Standstills or re-advances during the recession of the Taylor Lobe of the TRGC resulted in the emplacement of numerous recessional moraines, which, when dated, provide a detailed chronology of ice retreat within the valley. The delineation of TRGC trimline and moraine features facilitates paleo-glacier reconstruction, providing constraints for the modeling of ice thickness and ice surface extrapolation. Estimated equilibrium-line altitudes (ELAs) associated with reconstructed ice extents in the Taylor River Valley reflect shifts in glacier mass balance related to local and regional-scale climate changes through the last glacial-interglacial transition.