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Martian swirls and curlicues

glacial features in depression on Mars
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, is a great example of how a well known geological process on Earth, glaciers, can form features on Mars that appear most inexplicable.

The image was taken on May 13, 2020 and highlights the geology found in a depression, likely an eroded crater, on the northwest flanks of one of Mars’ largest basins, Argyre Planitia, located in the planet’s southern cratered highlands. The basin is thought to have been formed by a giant impact during the Late Heavy Bombardment around 3.9 billion years ago, when the inner terrestrial planets were sweeping up the last remnants of the Sun’s accretion disk, with that process causing the many craters we see on the Moon, Mercury, and Mars

This particular depression is at 41 degrees south latitude, in the mid-latitudes where scientists have found much evidence of buried glaciers. This is likely what we are looking at here. The section I’ve cropped has a dip to the south, which somewhat fits these flow features. If you look at the full image, you will see comparably weird flow features south of this section, flowing downhill in the opposite direction, to the north.

The problem is that not all the features fit the direction of flow, or any flow at all. I suspect we are seeing evidence of the waxing and waning of glaciers over this terrain over many eons. Disentangling that history however is confounding, especially when we are limited to only studying such objects from orbit.

I must also add that this image was labeled by the MRO science team a “terrain sample,” which means it wasn’t specifically requested by any scientist studying this geology. Instead, they needed to take an image to maintain the spacecraft’s camera temperature, and picked this spot for that snapshot. Their choice wasn’t random, but it also wasn’t based on any focused research.

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  • Cotour

    Call Richard Hoagland!

    There is a “boot” temple constructed on Mars! I see it in that picture.

    Wait, maybe it a a galoshes temple.

    It must be a temple to the extinct fisherman of Mars?

  • mpthompson

    I’m curious about the hypothesized glaciers on Mars that someone might be able to answer. Is it generally assumed the great bulk ice that comprised the glaciers are still present but now buried under hundreds of millions of years of windblown dust and debris? Or, has the bulk of the ice that once comprised the glaciers sublimated away over the eons and we essentially see the dry buried footprints of these former giants. I guess I’m asking because I see so many pictures where it is suggested we are looking at glaciers, but all I ever see to my untrained eye is a dusty dry wasteland.

    On Earth when I think of glaciers, I’m thinking of an immense white river of ice creakily winding its way down a mountain pass or filling a valley that empties into a sea. If there were glaciers at the Martian middle latitudes, wouldn’t there still be some evidence of large expanses of white ice?

  • mpthompson: The ice on Mars is not white because it is buried under a layer of dust and debris, which does not need to be very thick to protect it from sublimating away.

    1. The ice on Mars is thought to shift from the poles the mid-latitudes, and back, depending on the planet’s obliquity (its rotational tilt). When it is tilted a lot (more than 45 degrees), the mid-latitudes are colder than the poles and the ice shifts towards the equator. When the tilt is close to zero things reverse, and ice shifts to the poles. Right now, with the tilt at about 25 degrees, it appears that the situation is in steady state. This is why scientists presently believe the buried glaciers they see are not active. See this post for more info: The edge of Mars’ north polar ice cap

    2. See this post for guidance on how the scientists identify these buried glaciers: How to spot a glacier on Mars Even though the ice is buried, the glacial features are visible through that somewhat thin debris covering.

    3. If you do a search on BtB for “glaciers” and “Mars” you will get many of my cool image posts of glacial features. Pay especial close attention to the different look of craters in the northern mid-latitudes vs the equatorial regions. There craters look rough, solid, and rocky, while in the mid-latitudes they look softer, with a look of pudding, like the impact occurred in soft squishy ice that melted at impact but then froze thereafter.

    I should post more images of features that are not in the mid-latitudes and don’t have these glacial features. A look at many of my images in the area of Arsia Mons and Olympus Mons would give you a sense of the parts of Mars that have little water or buried glaciers.

    I hope that helps.

  • Star Bird

    And the Martian Ice Cap is said to grow and shrink with the seasons buts its been well of a Century since Wells wrote his book WAR OF THE WORLDS

  • mpthompson

    Bob, thanks for the detailed reply. I’ll look over your suggested links.

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