If you’ll travel back in time 3.5 billion years, what would Mars look like? the image is evolving among scientists working with NASA’s Curiosity rover.
Imagine ponds dotting the ground of Gale Crater, the 100-mile-wide (150-kilometer-wide) ancient basin that Curiosity is exploring. Streams may need laced the crater’s walls, running toward its base. Watch history in fast forward, and you’d see these waterways overflow then dry up, a cycle that probably repeated itself numerous times over many years.
That is the landscape described by Curiosity scientists during a Nature Geoscience paper published today. The authors interpret rocks enriched in mineral salts discovered by the rover as evidence of shallow briny ponds that went through episodes of overflow and drying. The deposits function a watermark created by climate fluctuations because the Martian environment transitioned from a wetter one to the freezing desert it’s today.
Scientists would really like to know how long this transition took and when exactly it occurred. This latest clue could also be a symbol of findings to return as Curiosity heads toward a neighborhood called the “sulfate-bearing unit,” which is predicted to possess formed in a good drier environment. It represents a stark difference from lower down the mountain, where Curiosity discovered evidence of persistent freshwater lakes.
Read More: www.nasa.gov