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I guess these would be formed by lava flows from previous tectonic activity?

• kibwen 5y ago
  Some of them, but Mars also used to have liquid water so they could have also been formed by erosion.
  • foobarbecue 5y ago
    Interesting... do you have any more information on this? My impression from studying this was that that dissolutional karst would probably not last the hundreds of millions or few billions of years kind of timeframe that separates us from when liquid water was prevalent on Mars. However, I'm not sure if that impression is based on good assumptions -- the oldest caves on earth are thought to be about 340 million years old but the processes that act to remove caves on earth are probably far more active than what goes on on Mars, so maybe there are caves on Mars from a wet period that still exist. However, my impression from working with people on mars and moon cave projects is that the community generally thinks that the entrances that have been found are lava tube collapse features, or related to impacts or small-scale tectonism.
• shonenknifefan1 5y ago
  > Types of cave entrances identified in the catalog include lava tube skylights, deep fractures, Atypical Pit Craters (APCs), and other void spaces in karst-similar terrains. The cave candidates that they displayed in the image were all in the Tharsis Montes surrounding the major martian volcanos in the most volcanic region of Mars, so I suspect that those ones are largely lava tubes.