HiRISE Updates Week of 2017 May 22

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HiRISE Updates Week of 2017 May 22

Post by bystander » Fri May 26, 2017 6:29 pm

Alfred McEwen wrote:

Erosion of the Edge of the South Polar Layered Deposits (ESP_013224_1080)

This oblique view of the sloping edge of the stack of icy layers over the South Pole has some interesting morphologies.

The slope appears to be eroding from a combination of landslides, block falls, and sublimation. The bright icy exposure in the larger landslide scar (upper right) suggests that this was a relatively recent event.

Small-scale textures over the scene are due to both blowing wind and the thermal expansion and contraction of shallow ice.

This is a stereo pair with ESP_013026_1080.
Kristin Block wrote:

Dune Ripples in Her Desher Vallis (ESP_020562_1550)

These small ripples, about 10 meters apart, are located in Her Desher Vallis. Her Desher is a small channel that shows evidence of phyllosilicates—silicates with a sheet-like structure, such as clay minerals.

Much larger images of this area show that Her Desher Vallis appears isolated, with no obvious connections to craters or larger valleys. Her Desher, the ancient Egyptian name for Mars, translates to “the Red One.”

This is a stereo pair with ESP_013771_1550.
Alfred McEwen wrote:

An Oblique View of Uplifted Rocks (ESP_021545_1660)

This image shows part of the central uplifted region of an impact crater more than 50 kilometers wide. That means that the bedrock has been raised from a depth of about 5 kilometers, exposing ancient materials.

The warm (yellowish-reddish) colors mark the presence of minerals altered by water, whereas the bluish and greenish rocks have escaped alteration. Sharp-crested ridges and smooth areas are young windblown materials.

NB: North is approximately to the left in the cutout and wallpaper.

This is a stereo pair with ESP_013198_1660.
Alfred McEwen wrote:

Flow on the Rim of Tooting Crater (ESP_016412_2030)

This oblique view shows a small part of the near-rim ejecta from Tooting Crater. The flow extending from upper left to lower right looks much like a typical lava flow, but doesn’t emanate from a volcanic vent.

Instead, this must be either melted rock from the impact event, or a wet debris flow from melting of ice. The surface is dusty so color variations are minor.

This is a stereo pair with ESP_016135_2030.

Credit: NASA/JPL-Caltech/University of Arizona

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