3rd-assignment

Remnants of a Viscous Flow on Mars
http://www.uahirise.org/ESP_028352_2245

Lobate flows are common in the Martian mid latitude region (30-45 degrees latitude). Some are pristine-looking and highly reminiscent of terrestrial glaciers, whereas others appear more degraded. The flow deposit shown here is a good example of a degraded flow deposit.

The uphill "head" toward the right of the image has carved out an amphitheater-shape into the escarpment, and the "toe", to the right, is lobate in shape. The surface is highly degraded and eroded, and the deposit shows evidence of deflation (loss of volume, probably from the sublimation of ice), as lateral moraines (ridges running along the length of the feature) are visible.



A Pedestal Crater in the Northern Mid-Latitudes
http://www.uahirise.org/ESP_028598_2230

This image is of a pedestal crater at 43 degrees north. The lobate pattern around the circular crater is where the crater ejecta landed. This area is now raised above the level of the surrounding plains, forming a mesa, or plateau, with the crater at the center.

This suggests that at one time the surface of the whole region was at this level. The ejecta from the crater covered the area near the crater and protected it, while the surrounding region was eroded away, leaving the crater high standing. This material may have been removed because it was loose and/or cemented with ice.

Pedestal craters are particularly interesting because some ice may still be present in the mesa, protected by the ejecta surface.