LONG-TERM SURFACE WEATHERING ALONG A ROCK GLACIER IN THE SOUTH FORK OF WRIGHT VALLEY, EAST ANTARCTICA

In the McMurdo Dry Valleys, the South Fork of Wright Valley is barren of exposed glacial ice. Yet, a 7-km long rock glacier extends across western South Fork below a cover of boulders, desert pavement, and sandy soils. Talus from steep dolerite, gneiss, granitic, and sandstone cliffs fans out onto the rock glacier, adding lithics and possibly ice cement. The character of the rock glacier is thus determined by a combination of its mechanism of formation, climate, and the weathering of lithics input to the surface of the feature. We will examine the weathering products at the surface of the South Fork rock glacier on a long-axis transect and several short-axis transects. These transects extend from modern rockfall deposits to very old pavement surfaces, and cross numerous boundaries between talus lithology. Grain size, mineral composition, and results of major ion leaching will inform our understanding of rock glacier development in the context of a very cold and arid climate. This in turn will improve our interpretations regarding the influence of rock glaciers in Dry Valleys sediment deposition, sediment weathering, and downstream hydrology.