Mars magmas once contained a lot of water, researchers from MIT and U. of Tennessee report.
Finding suggests that volcanos helped bring water to the planet's surface millions of years ago.
Scientists say that channels on Mars's surface may have been carved by flowing water and an ancient ocean may have existed there, but little is known about the source of the water. One possible source is volcanic degassing, in which water vapor is produced by magma spewing from volcanos, but the Martian rocks that have reached Earth as meteorites have notoriously low water content. This study shows that before the molten rock that crystallized to form Martian meteorites was erupted on the surface of the planet, it contained as much as 2 percent dissolved water. When magma reaches the planet's surface, the solubility of water in the molten liquid decreases and the water forms vapor bubbles and escapes as gas. The process is similar to the release of gas bubbles that occurs when you open a can of soda.