NASA’s Curiosity Rover Finds ‘Ancient Oasis’ on Mars

The network of cracks in this Martian rock slab called "Old Soaker" may have formed from the drying of a mud layer more than 3 billion years ago (via NASA/JPL-Caltech/MSSS)

NASA’s Curiosity rover may have discovered an ancient oasis on Mars.

Rocks enriched in mineral salts provide evidence of shallow ponds that may have once dotted the 100-mile-wide Gale Crater.

As described in a paper published by the journal Nature Geoscience, briny pools likely experienced repeated episodes of overflow and drying, leaving behind billion-year-old clues.

These deposits, recently uncovered by NASA’s rover, point to climate fluctuations as the Martian environment transitioned from a wet habitat to a freezing desert.

In 2017, Curiosity visited a 500-foot-tall section of sedimentary rock known as Sutton Island, where an accumulation of salt suggests water not only evaporated, but concentrated into brine.

Typically, when a lake dries up, it leaves behind piles of pure salt crystals. But the Sutton Island salts are different: They’re mineral salts, not table salt.

And they are mixed with sediment, suggesting they crystallized in a wet environment—possibly just beneath dissipating shallow ponds filled with briny water.

The NASA rover previously found evidence of freshwater lakes elsewhere on Mars.

“We went to Gale Crater because it preserves [the] unique record of a changing Mars,” lead study author William Rapin, a postdoctoral scholar at Caltech, said in a statement. “Understanding when and how the planet’s climate started evolving is a piece of another puzzle.”

Sutton Island may have once resembled saline lakes on South America’s Altiplano, where streams and rivers flowing from mountain ranges into an arid, high-altitude plateau lead to closed basins similar to Gale.

“During drier periods, the Altiplano lakes become shallower, and some can dry out completely,” Rapin explained. “The fact that they’re vegetation-free even makes them look a little like Mars.”

These salt-enriched rocks are just one clue among many the rover team is using to piece together the nearby world’s atmospheric conditions.

Looking across the entirety of Curiosity’s journey—which began in 2012—scientists see a cycle of wet-to-dry across long timescales.

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