NASA scientists are examining a new potential evidence of ancient drying on the red planet. The Mars Curiosity rover found a network of cracks which probably originated from drying mud on a site called Old Soaker in lower Mount Sharp. This is the first time that NASA discovered something like mud cracks on Mars. They are also currently watching for more similar-looking sites.
Ancient Mars is believed to be warmer and wetter. Previously, some scientists suggested a theory that there was huge presence of liquid water on Mars for a very long time -- not just in small, periodic timeframes. This was after they found a sedimentary rock which was formed on the surface of Mars about 3.8 billion years ago. Meanwhile, the Mars Curiosity rover also previously found evidences of ancient lakes.
Curiosity science team member Nathan Stein, who is leading the investigation on Old Soaker said that what they found are most likely mud cracks, technically called desiccation cracks. "Even from a distance, we could see a pattern of four- and five-sided polygons that don't look like fractures we've seen previously with Curiosity. It looks like what you'd see beside the road where muddy ground has dried and cracked," Stein said according to NASA.
The timeline when the mud cracks were presumably formed coincides with the previously discovered sedimentary rocks. NASA researchers revealed it was formed more than 3 billion years ago according to Sci-News. The cracked layer was buried by other layers of sediment which was later stripped away due to wind erosion.
Aside from the cracks, other evidences of ancient drying were also found by the Mars Curiosity rover. This includes sandstone and mudstone layers as well as a pattern called cross-bedding. This pattern can only be formed near a shore of a lake where there is strong flow of water or from windblown sediment. Curiosity is tasked on investigating the ancient habitability of Mars.