https://techcrunch.com/2019/10/07/mars-curiosity-rover-finds-evidence-of-an-ancient-oasis-on-mars/

On its latest trek through the Gale Crater on Mars, the Curiosity Rover has discovered evidence that’s leading . scientists to believe that there was an oasis at the base of that 150-kilometer-wide crater.

Curiosity scientists described the scene in an article in “Nature Geoscience” published earlier this week. Researchers analyzing data from the Rover are extrapolating from the data that rocks enriched by mineral salts are evidence of briny ponds that went through periods of drying out and overflowing.  Those deposits serve as a watermark made by climate fluctuations as Mars’ climate changed from a wet one to the current frigid ice desert it is today.