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P. C. Thomas (Cornell University)
Mapping of forms across the south polar residual cap and comparison of imaging taken in different Mars years show the residual cap to be the site of multiple episodes of deposition and erosion. Residual exposures of distinctive layered units, consistently about 11 m in thickness, have been embayed by later deposition of layers, themselves eroded, buried, and in some areas suffering measurable current erosion (Malin et al. Science 294, 2146,2001). Different units currently are eroding at different rates. Wind modifies the shapes of many depressions in the south residual cap deposits. The presence of similar units at very different elevations indicates depositional episodes to be dependent on more than local factors. Instances of inverted relief testify to deposition of materials of contrasting physical properties, in addition to the simple presence of layers. Geographical variations of the type of depressions and their orientations also suggest complex controls of the type of polar sedimentation involved.
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Bulletin of the American Astronomical Society, 34, #3< br> © 2002. The American Astronomical Soceity.