Mars is a lot like Earth in many ways. The signs of water are obvious in the deep valleys. Many have speculated about once vast oceans often centered over the northern part of Mars. Where did the water go? Extensive radar mapping of the middle latitude region of northern Mars shows that thick masses of buried ice are quite common beneath protective coverings of rubble. NASA's Mars Reconnaissance Orbiter has charted the locations of these hidden glaciers and ice filled valleys which were first confirmed by radar two years ago.
The Martian subsurface ice deposits extend for hundreds of miles, in the rugged region called Deuteronilus Mensae, about halfway from the equator to the Martian north pole. The ice, up to 1 kilometer (0.6 mile) thick, is found adjacent to steep cliffs and hillsides, where rocky debris from slopes covers and protects the ice from sublimation into the atmosphere.
The studied area is centered at 42.2 degrees north latitude and 24.7 degrees east longitude. It covers an area 1050 kilometers by 775 kilometers (650 miles by 481 miles).
The Shallow Radar instrument on the orbiter has obtained more than 250 observations of the study area, which is about the size of California.
"We have mapped the whole area with a high density of coverage," Jeffrey Plaut of NASA's Jet Propulsion Laboratory said. "These are not isolated features. In this area, the radar is detecting thick subsurface ice in many locations." The common locations are around the bases of mesas and scarps, and confined within valleys or craters.
Plaut said, "The hypothesis is the whole area was covered with an ice sheet during a different climate period, and when the climate dried out, these deposits remained only where they had been covered by a layer of debris protecting the ice from the atmosphere."
NASA had earlier reported that buried glaciers lie in the Hellas Basin region of Mars' southern hemisphere.
Three studies appearing in the March 17, 2005 issue of the journal Nature add to a growing body of evidence that points to recent liquid water and present vast stores of underground ice near the planet's equator. Explosive eruptions about 350 million years ago created depressions on the flanks of the volcano Hecates Tholus, according to a study led by Ernst Hauber of the German Aerospace Center. And just five million years ago, glacial deposits formed inside these depressions, the scientist concludes.
The evidence on Mars suggests that long ago flowing water, oceans and glaciers and a world that once had a vast and changing climate existed.
For further information: http://www.jpl.nasa.gov/news/news.cfm?release=2010-072&rn=news.xml&rst=2505