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New findings from NASA\u2019s Curiosity Mars rover could provide an answer to the mystery of what happened to the planet\u2019s ancient atmosphere and how Mars has evolved over time.<\/p>\n
Researchers have long believed that Mars once had a thick, carbon dioxide-rich atmosphere and liquid water on the planet\u2019s surface. That carbon dioxide and water should have reacted with Martian rocks to create carbonate minerals. Until now, though, rover missions and near-infrared spectroscopy analysis from Mars-orbiting satellites haven\u2019t found the amounts of carbonate on the planet\u2019s surface predicted by this theory.<\/p>\n
Reported in an April paper in Science, data from three of Curiosity\u2019s drill sites revealed the presence of siderite, an iron carbonate mineral, within the sulfate-rich rocky layers of Mount Sharp in Mars\u2019 Gale Crater.<\/p>\n
\u201cThe discovery of abundant siderite in Gale Crater represents both a surprising and important breakthrough in our understanding of the geologic and atmospheric evolution of Mars,\u201d said Benjamin Tutolo, associate professor at the University of Calgary, Canada, and lead author of the paper.<\/p>\n
To study the Red Planet\u2019s chemical and mineral makeup, Curiosity drills three to four centimeters down into the subsurface, then drops the powdered rock samples into its CheMin instrument. The instrument, led by NASA\u2019s Ames Research Center in California\u2019s Silicon Valley, uses X-ray diffraction to analyze rocks and soil. CheMin\u2019s data was processed and analyzed by scientists at the Astromaterials Research and Exploration Science (ARES) Division at NASA\u2019s Johnson Space Center in Houston.<\/p>\n
\u201cDrilling through the layered Martian surface is like going through a history book,\u201d said Thomas Bristow, research scientist at NASA Ames and coauthor of the paper. \u201cJust a few centimeters down gives us a good idea of the minerals that formed at or close to the surface around 3.5 billion years ago.\u201d<\/p>\n
The discovery of this carbonate mineral in rocks beneath the surface suggests that carbonate may be masked by other minerals in near-infrared satellite analysis. If other sulfate-rich layers across Mars also contain carbonates, the amount of stored carbon dioxide would be a fraction of that needed in the ancient atmosphere to create conditions warm enough to support liquid water. The rest could be hidden in other deposits or have been lost to space over time.<\/p>\n
In the future, missions or analyses of other sulfate-rich areas on Mars could confirm these findings and help us better understand the planet\u2019s early history and how it transformed as its atmosphere was lost.<\/p>\n
Curiosity, part of NASA\u2019s Mars Exploration Program (MEP) portfolio, was built by NASA\u2019s Jet Propulsion Laboratory, which is managed by Caltech in Pasadena, California. JPL leads the mission on behalf of NASA\u2019s Science Mission Directorate in Washington.<\/p>\n
For more information on Curiosity, visit:\u00a0<\/p>\n
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News Media Contacts<\/strong>\u00a0<\/p>\n Karen Fox \/ Molly Wasser\u00a0 Andrew Good\u00a0
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov\u202f\/\u202fmolly.l.wasser@nasa.gov\u00a0<\/p>\n
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov<\/p>\n<\/div>\n