New images taken by NASA's Perseverance rover may show signs of what was once a rollicking river on Mars, one that was deeper and faster-moving than scientists have ever seen evidence for in the past. The river was part of a network of waterways that flowed into Jezero Crater, the area the rover has been exploring since landing more than two years ago.
Understanding these watery environments could help scientists in their efforts to seek out signs of ancient microbial life that may have been preserved in Martian rock.
Perseverance is exploring the top of a fan-shaped pile of sedimentary rock that stands 820 feet (250 meters) tall and features curving layers suggestive of flowing water. One question scientists want to answer is whether that water flowed in relatively shallow streams – closer to what NASA's Curiosity rover has found evidence of in Gale Crater – or a more powerful river system.
Years ago, scientists noticed a series of curving bands of layered rock within Jezero Crater that they dubbed "the curvilinear unit." They could see these layers from space but are finally able to see them up close, thanks to Perseverance.
When viewed from the ground, the curved layers appear arranged in rows that ripple out across the landscape. They could be the remnants of a river's banks that shifted over time – or the remnants of sandbars that formed in the river. The layers were likely much taller in the past. Scientists suspect that after these piles of sediment turned to rock, they were sandblasted by wind over the eons and carved down to their present size.
"The wind has acted like a scalpel that has cut the tops off these deposits," said Michael Lamb, professor of geology and a Perseverance science team collaborator. "We do see deposits like this on Earth, but they're never as well exposed as they are here on Mars. Earth is covered in vegetation that hides these layers."
Read the full story at JPL News.