Accumulations of rocky debris at the base of bedrock escarpments on Mars have mean inclinations of 20°, well below the angle of repose ( 35°). These inclinations decrease with increasing latitude, suggesting a climatic influence. We present evidence that these low inclinations are the result of gravitational creep driven by repeated deposition and sublimation of ground ice. We estimate the rates of bedrock erosion and ice-driven creep on Mars and use a simple model to show that the probable time scale for debris slope development is between 20 Myr and 2 Gyr. Our results suggest that water ice has shaped Martian landscapes throughout the late Amazonian period. INDEX TERMS
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