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PASADENA, Calif., Dec. 8 (UPI) -- Given the number of selfies that Curiosity snaps on a weekly basis, one might be tempted to rename the Mars rover "Vanity." But what's good for Curiosity's self-satisfaction is also good for science, as the Martian rover continues to capture compelling images of the Red Planet.
The rover's most recent selfie background is a place called Windjana, a sandstone outcropping in the portion of Gale Crater known as the Kimberley region. One of Mars' largest mountains, Mount Sharp, rises from the middle of Gale Crater. Curiosity has plans to ascend at least part of the 18,000-foot mountain, but for now it is simply exploring the area around Mount Sharp's base.
On its way through Windjana and the Kimberley region, the rover happened upon evidence that suggests Gale Crater was once a lake. Researcher at NASA say the Mount Sharp likely formed as water delivered layer upon layer of sediment to the center of the lakebed -- carried there by a series of alluvial fans and river deltas.
"During wet periods, water pooled in lakes where sediments settled out in the center of crater," NASA said on a call with reporters. "Even during dry periods in the crater center, groundwater would have existed beneath the surface. Then, during the next wet period it would resurface to form the next lake. This alternation of lakes, rivers and deserts could have represented a long-lasting habitable environment."
Previously, scientists have surmised that Mount Sharp was the product of wind-driven sediment deposits. But now researchers suggest Curiosity has discovered evidence of water-powered sediment deposits -- ancient evidence uncovered by erosion.
"We found sedimentary rocks suggestive of small, ancient deltas stacked on top of one another," Curiosity scientist Sanjeev Gupta, a researcher at the Imperial College in London, said in a press release. "Curiosity crossed a boundary from an environment dominated by rivers to an environment dominated by lakes."
As usual, researchers say more testing and exploration is necessary to arrive at a definitive answer about Mount Sharp's origins. But after years of uncertainty as to how such a massive formation rose form the center of a crater, scientists are excited by Curiosity's new discovery.
"If our hypothesis for Mount Sharp holds up, it challenges the notion that warm and wet conditions were transient, local, or only underground on Mars," said Ashwin Vasavada, lead Curiosity scientist at NASA's Jet Propulsion Laboratory. "A more radical explanation is that Mars' ancient, thicker atmosphere raised temperatures above freezing globally, but so far we don't know how the atmosphere did that."
