San Francisco (CA) - NASA is reporting that their Mars Reconnaissance Orbiter has discovered a vast field of a "long sought-after mineral" on Mars, called carbonate. Using the craft's Compact Reconnaissance Imaging Spectrometer (CRISM), the finding indicates Mars had neutral to alkaline water as far back as 3.6 billion years ago. This indicates the Martian planet has remained watery, increasing greatly the possibility that it has supported life.
Scott Murchie, of the Johns Hopkins University Applied Physics Laboratory, says, "We're excited to have finally found carbonate minerals because they provide more detail about conditions during specific periods of Mars' history."
NASA will publish a complete record of their findings in the December 19, issue of Science Magazine. They gave an announcement earlier today at the American Geophysical Union's Fall Meeting in San Francisco.
Carbonate rocks are created when water and carbon dioxide interact with calcium, iron or magnesium found in volcanic rocks. CO2 from the atmosphere becomes trapped within the porous rocks. This accounts for a huge amount of trapped CO2. To put it into perspective, were all of the CO2 trapped in Earth's volcanic rocks released, our atmosphere would be thicker than that of Venus, according to NASA.
Researchers are theorizing that thick CO2 in the past may have kept the Martian surface warm and habitable. Having a warm environment with a liquid watery surface means that the possibility of life there is now more probable than we've ever thought possible (at least from an science observation point of view).
Bethany Ehlmann, lead author of the Science Magazine article and a spectrometer team member from Brown University, said, "The carbonates that CRISM has observed are regional rather than global in nature, and therefore, are too limited to account for enough carbon dioxide to form a thick atmosphere.
"Although we have not found the types of carbonate deposits which might have trapped an ancient atmosphere, we have found evidence that not all of Mars experienced an intense, acidic weathering environment 3.5 billion years ago, as has been proposed. We've found at least one region that was potentially more hospitable to life."
Carbonate was observed in a "clearly defined" layer of bedrock approximately 925 miles in diameter at the Isidis impact basin. The best exposed rocks occur along a trough system called Nili Fossae, which is 414 miles long at the edge of the basin. The region also has rocks enriched with olivine, another mineral which can react with water to form carbonate.
While NASA's Phoenix Mars Lander has previously discovered carbonates in soil samples, and they have been seen in Martian meteorites that have fallen to Earth, the dust and soil mixture sources have been unclear. Researchers now believe the carbonates formed over long, extended periods during "early Mars."
Research into this effort was carried out by the Applied Physics Laboratory's effort and development of CRISM for Mars. The device is operated by a team from various universities, the government and the private sector. NASA's Jet Propulsion Laboratory manages the Mars Reconnaissance Orbiter mission for NASA's Science Mission Directorate, located in Washington, D.C.