Scientists Discover Signs of Ancient Water Activity on Mars

Scientists have discovered signs of ancient water activity on Mars in a now- dried up lake system, adding to growing evidence that the Red Planet was once habitable for life, according to a new study.

The ancient lake at Jezero crater, located near the planet's equator, was first identified in 2005, and now Brown University researchers are saying that the onslaught of water that filled the crater was one of at least two separate periods of water activity in the region. It's hard to say just how long this lake system was active, but scientists speculate that it dried out approximately 3.5 to 3.8 billion years ago.

"We can say that this one really well-exposed location makes a strong case for at least two periods of water-related activity in Mars' history," Tim Goudge, who led the research, said in a news release. "That tells us something really interesting about how early Mars operated."

The lake's water supply supposedly came from two channels on the northern and western sides of the crater, which, at times, was brimming with so much water that any extra spilled into a third large channel. While it was still active, the lake system also deposited sediment in a delta-like deposit that, it turns out, contains traces of clay minerals - a clear sign of alteration by water.

However, 10 years after its initial discovery, Brown researchers wanted to learn exactly how those minerals formed - an issue that remains up for debate. Either the minerals formed in place in the lake, or they formed elsewhere and were transported into the lake.

To find out, Goudge and his colleagues collected high-resolution orbital images from NASA's CTX instrument, and combined them with data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard NASA's Mars Reconnaissance Orbiter. Using this data, they put together a detailed geological and mineralogical map of the entire Jezero crater paleolake system.

What they found was that each of the sediment deposits has its own distinct mineral signature that matches the signature of the watershed that it came from.

"That's a good indication that the minerals formed in the watershed and were then transported into the lake," Goudge said. (Scroll to read on...)