DIRECT QUANTIFICATION OF CURRENT SEDIMENT TRANSPORT ON MORAINE SURFACES IN CASCADE MOUNTAINS, WA, USA

The stability of ground surface and preservation of landforms that record past events and environments is of great importance as the geologic and climatic history is evaluated. Moreover, many dating methods such as lichenometry and cosmogenic isotope dating rely on stability and preservation of the dated surfaces. Although long term (10's of kyrs) degradation estimates of the landforms such as fault scarps and moraines suggest significant erosion, only few direct observations exist on the present regolith transportation. Soil traps and repeat photography sites were installed on three moraine surfaces of widely varying age (0.15 to over 100 kyrs) in the Cascade Mountains, WA. The current sediment transport rates based on the trapped sediment quantities and repeat photography over one year will be reported. These results are compared to the long term mean sediment transport rates that are largely based on the observed differences in cross profiles of fault scarps and moraines of vastly varying age.