NASA's Curiosity Mars rover recently examined slabs of rock cross-hatched with shallow ridges that may have originated as cracks in drying mud, scientists using the craft reported Tuesday.
"Mud cracks are the most likely scenario here," said Curiosity science team member Nathan Stein, a graduate student at Caltech in Pasadena, California, said in the NASA article.
If Stein is correct, they would be the first mud cracks confirmed by the Curiosity mission, and would offer evidence that sediments deposited a long time ago included some drying after wetter conditions.
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The cracked layer formed more than 3 billion years ago and was subsequently buried by other layers of sediment, all becoming stratified rock, NASA reported.