spacetoday.net: Carbonates found on Mars

Posted: Sat, Dec 20, 2008, 11:55 AM ET (1655 GMT)
Scientists announced this week that they have detected carbonate minerals on Mars, a finding that provides new insights into the early watery history of Mars. In a paper published in Friday's issue of the journal Science, researchers reported that they had detected carbonates using the Compact Reconnaissance Imaging Spectrometer instrument on NASA's Mars Reconnaissance Orbiter spacecraft. Carbonates are minerals formed in the presence of water and carbon dioxide, and their detection had long been a goal of scientists seeking to understand the early history of Mars. The carbonates are located only in scattered regions of the planet and not globally, suggesting that they are not associated with a thick carbon dioxide atmosphere that scientists believe Mars has early in its history, keeping the planet warm enough for liquid water to flow. However, the existence of the carbonates, which require neutral or alkaline conditions, implies that not all of the planet had acidic conditions three billion years ago.