Investigation of Postglacial Sediment Storage and Transport in Garnet Canyon, Teton Range, Wyoming

Abstract

The Teton Mountains are shaped by interactions between glacial, fluvial and mass wasting processes. In this study we investigate the influence of process interactions on quantitative estimates of erosion rates based on sediment transport and accumulation. Sediment characteristics were measured on talus fan and stream channel deposits. These observations were used to evaluate weathering and rounding, which can indicate transport history and mixing between the two deposits and processes. Talus fans were studied to quantify the stability of fan surfaces and determine the frequency of material transport. Streams were studied to determine the efficiency of meltwater flow to move sand and coarser materials deposited on talus surfaces. Similarities between sediments in the fluvial and talus deposits support strong coupling between these processes. Streams are capable of moving smaller sized talus materials, however active rockfalls continue to supply new sediment and limit stream incision. The source of recent rockfalls appears to be ridges at high elevations or along north facing walls indicated by the frequency of surface weathering and lichen cover on selected talus fans.