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Residue ice in southern mid-latitude Martian crater?

Residue ice in the southern mid-latitudes of Mars?
Click for original image.

Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on April 10, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows an unnamed 1.2-mile-wide crater at about 35 degrees south latitude with what appears to be residual glacial ice hugging its north interior wall.

As this is in the southern hemisphere, the ground immediately below the south-facing interior wall of the crater is going to be in shadow the most, and thus it will also be the place where any surface or near-surface ice will survive the longest. In this case it appears that from the bumpy nature of that residual ice it has also been sublimating away. Within it however remains the faint hint of multiple layers, suggesting about a dozen past climate cycles with each new cycle producing a new but smaller layer with less ice.

The material in the southern half of the crater floor appears to be dust formed into ripple dunes.

Overview map

The white dot south of Solus Planum marks this location on the overview map to the right. On the full image the channel that the crater impact appears to have cleaved is much longer, and follows the general grade in this region downhill to the south. Within the full picture however the grade is not obvious. The crater itself is tilted to the west, with the rim on the east almost 500 feet higher than the rim on the west.

As always, our Earth-based perspective makes us think the channel was carved by flowing water. The rough and inconclusive downhill grade however suggests instead a slow glacial flow, but that is entirely my own uneducated opinion.

Regardless, the material in the northern half of this crater’s floor strongly implies the presence of glacial ice, an implication strengthened by the fact that the interiors of all the nearby craters have similar material, all hugging each crater’s north interior wall.

Genesis cover

On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.

 
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.


The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
 

"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News

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