HiRISE Updates Week of 2017 Feb 20

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HiRISE Updates Week of 2017 Feb 20

Post by bystander » Fri Feb 24, 2017 7:11 pm

Colin Dundas wrote:

A New Crater on a Dusty Slope (ESP_048686_1785) (HiClip)

This image shows a new impact site originally detected by the Context Camera onboard MRO. The crater is on a dusty slope, which also has several dark slope streaks due to dust avalanches.

A previous impact at another place on Mars triggered a major dust avalanche, but this one did not. This tells us that the dust here is more stable (stronger and/or on a lower slope).
Colin Dundas wrote:

Obstacles and Wakes in Lava (ESP_048745_2095) (HiClip)

Amazonis Planitia is a broad plain on Mars, covered with ancient lava. This image shows an interesting feature of an old lava flow.

When it was mostly liquid, the lava had a crust of cooled debris floating on the surface. Here, the crust just barely scraped over some hills. The flow was able to make it past the hills, but the rubble crust was caught and piled up, forming thick masses of debris.

Downstream from the hills, there was no crust left and the lava formed a smoother, fresh surface. Observations like this tell us about the scale of the lava flow (which must have been a huge sheet) and also which direction it was moving at the time when the crust interacted with the hills.
Dan Berman wrote:

Layered Mantling Deposits in the Northern Mid-Latitudes (ESP_048897_2125) (HiClip)

Ice-rich mantling deposits accumulate from the atmosphere in the Martian mid-latitudes in cycles during periods of high obliquity (axial tilt), as recently as several million years ago.

These deposits accumulate over cycles in layers, and here in the southern mid-latitudes, where the deposits have mostly eroded away due to warmer temperatures, small patches of the remnant layered deposits can still be observed.
Alfred McEwen wrote:

Colorful Bedrock Layers (ESP_049009_1520) (HiClip)

Much of Mars’ surface is covered by fine-grained materials that hide the bedrock, but elsewhere, such as in this scene, the bedrock is well exposed (except where covered by sand dunes).

Colors are enhanced in the cutout of a pit exposing reddish layers. This is part of a stereo pair, so check out the stereo anaglyph for a 3D view.

This is a stereo pair with ESP_039581_1520.

Credit: NASA/JPL-Caltech/University of Arizona

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