Volcanoes erupted  beneath an ice sheet on Mars billions of years ago, far from any ice  sheet on the Red Planet today, new evidence from NASA's Mars  Reconnaissance Orbiter suggests. 

   The research about  these volcanoes helps show there was extensive ice on ancient Mars. It  also adds information about an environment combining heat and moisture,  which could have provided favorable conditions for microbial  life.Sheridan Ackiss of Purdue University, West Lafayette, Indiana, and  collaborators used the orbiter's mineral-mapping spectrometer to  investigate surface composition in an oddly textured region of southern  Mars called "Sisyphi Montes." The region is studded with flat-topped  mountains. Other researchers previously noted these domes' similarity in  shape to volcanoes on Earth that erupted underneath ice."Rocks tell  stories. Studying the rocks can show how the volcano formed or how it  was changed over time," Ackiss said. "I wanted to learn what story the  rocks on these volcanoes were telling."When a volcano begins erupting  beneath a sheet of ice on Earth, the rapidly generated steam typically  leads to explosions that punch through the ice and propel ash high into  the sky. For example, the 2010 eruption of ice-covered Eyjafjallaj?kull  in Iceland lofted ash that disrupted air travel across Europe for about a  week.Characteristic minerals resulting from such subglacial volcanism  on Earth include zeolites, sulfates and clays. Those are just what the  new research has detected at some flat-topped mountains in the Sisyphi  Montes region examined with the spacecraft's Compact Reconnaissance  Imaging Spectrometer for Mars (CRISM), providing resolution of about 60  feet (18 meters) per pixel."We wouldn't have been able to do this  without the high resolution of CRISM," Ackiss said.The Sisyphi Montes  region extends from about 55 degrees to 75 degrees south latitude. Some  of the sites that have shapes and compositions consistent with volcanic  eruptions beneath an ice sheet are about 1,000 miles (about 1,600  kilometers) from the current south polar ice cap of Mars. The cap now  has a diameter of about 220 miles (about 350 kilometers).The Mars  Reconnaissance Orbiter Project has been using CRISM and five other  instruments on the spacecraft to investigate Mars since 2006. The  project is managed by NASA's Jet Propulsion Laboratory, Pasadena,  California, for the agency's Science Mission Directorate, Washington.  The Johns Hopkins University Applied Physics Laboratory in Laurel,  Maryland, provided and operates CRISM. Lockheed Martin Space Systems in  Denver built the orbiter and supports its operations.For more  information about this study, visit：http://www.nasa.gov/feature/jpl/found-clues-about-volcanoes-under-ice-on-ancient-mars