Click for full image.
It has been several months since my last Martian pit update, mostly caused by the lack of new pit images coming down from the high resolution camera on Mars Reconnaissance Orbiter (MRO). I think this lack is not because of a lack of additional pits or caves but instead signals the completion of a first high resolution survey of the known pits so far found on Mars. A full list of all past pit updates can be found at the bottom of this post.
Regardless, the image to the right, cropped to post here, is the only such image in months, taken on April 14, 2020, and shows a small isolated pit in the lava slopes between the giant volcanoes Arsia and Pavonis Mons. In the full photograph you can see how isolated is this pit. To the limits of the image there are no other such features, the terrain a relatively smooth plain with only some small ridges and and a scattering of what seem to be partly obscured or eroded small craters.
The overview below map shows this pit’s relationship to the volcanoes as well as to all other known nearby pits.
The white box indicates this pit’s location. The black boxes are all the other pits documented in earlier posts on Behind the Black. The nearest other pit to the north, highlighted in a post in February 2019, is very similar, a single sudden pit in the middle of a relatively featureless plain.
In fact, most of the pits in this area are alike, isolated pits with no other related features. If they are skylights into lava tubes, those tubes show no expression on the surface, which suggests they are either deep underground or simply don’t exist. The assumption that these pits are skylights into larger cave systems is based on Earth experience. On Mars however volcanic lava flow might express itself in different ways.
To better understand this geology we simply have to enter these pits and explore them.
All Martian pit posts since 2018:
- November 12, 2018
- January 30, 2019
- February 22, 2019
- April 2, 2019
- May 7, 2019
- July 1, 2019
- August 12, 2019
- September 20, 2019
- November 19, 2019
- November 26, 2019
- February 20, 2020
- February 28, 2020
- May 22, 2020
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