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NASA's Curiosity Rover has found that Mars' Mount Sharp was built by sediments deposited in a large lake bed over tens of millions of years, NASA announced Monday.
These clues from the Gale Crater suggest ancient Mars maintained a climate that could have produced long-lasting lakes at many locations on the Red Planet.
"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, Curiosity deputy project scientist at NASA's Jet Propulsion Laboratory, in a press release Monday. "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."
Researchers have been trying to determine why this layered mountain sits in a crater. Mount Sharp stands about three miles tall, its lower flanks exposing hundreds of rock layers — alternating between lake, river and wind deposits — that bear witness to the repeated filling and evaporation of a Martian lake much larger and longer-lasting than any previously examined close-up, according to the statement.
Here's more from NASA:
Curiosity currently is investigating the lowest sedimentary layers of Mount Sharp, a section of rock 500 feet (150 meters) high, dubbed the Murray formation. Rivers carried sand and silt to the lake, depositing the sediments at the mouth of the river to form deltas similar to those found at river mouths on Earth. This cycle occurred over and over again.
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Despite earlier evidence from several Mars missions that pointed to wet environments on ancient Mars, modeling of the ancient climate has yet to identify the conditions that could have produced long periods warm enough for stable water on the surface.