ROCK AVALANCHE SEDIMENTOLOGY AND GEOMORPHOLOGY

The deposits of large rock avalanches have sometimes been confused for moraines, incorrectly inferring past glacial activity and thus climatic conditions. While the sedimentological characteristics of glacial deposits are well-known qualitatively and quantitatively, a better knowledge of the characteristics of rock avalanches is warranted. Furthermore, a more complete understanding of how glacial rock avalanches evolve as they are rafted downglacier is needed. Here, we quantitatively describe the surface (carapace) sedimentology of a variety of large rock avalanches in western North America, including some that traveled over glaciers (Sherman, 1964; Black Rapids, 2002; Tyndall, 2015), over forested landscapes (Frank Slide, 1903), and over the Martian surface. We further describe the macro-level flow-feature geomorphology of glacial rock avalanches that have been advected by years or decades of glacier surface flow.