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Report: Mars could have icy equator

 Fields of cones like this one north of the Cerebus Plains could signal the presence of shallow ground ice on Mars
Fields of cones like this one north of the Cerebus Plains could signal the presence of shallow ground ice on Mars  

By Richard Stenger

(CNN) -- New satellite images from Mars strongly suggest that ground ice existed near the planet's equator in the recent geologic past, a discovery that could boost prospects for finding evidence of extraterrestrial life, scientists announced this week.

The high-resolution pictures, taken by the Mars Global Surveyor satellite, reveal bizarre landforms that likely formed due to the presence of frozen water just below the surface, University of Arizona researchers said. The ice could still be there today.

"If ground ice was present within 5 meters of the surface only a few million years ago, it is very likely to persist today within about the upper 10 meters," said planetary scientist Alfred McEwen.

"This is especially interesting because it is an equatorial region of Mars, more accessible to exploration."

Exploring Mars  
Destination Mars  

McEwen and colleagues in Arizona and Hawaii detected numerous clusters of small cones in satellite images of the Cerberus Plains, Marte Valles, and Amazonis Planitia region near the Mars equator, where summer daytime highs can peak at temperatures that would require only a sweater on Earth.

The martian cones are similar in size and shape to so-called rootless cones in Iceland, which form when surface lava interacts explosively with groundwater just below the surface.

The team estimated the martian lava flows took place as recently as 10 million years ago, a flash in the planet's more than 4 billion year history.

"If shallow ground ice in these regions was present less than 10 million years ago, deposits of shallow ground ice probably persist in the vicinity of the cone fields to the present day," the scientists concluded this week in the journal Geophysical Research Letters.

Rootless cones form when molten lava flows over water-soaked marshy channels. The top of the lava flow becomes encrusted. More magma pours through the enclosed pathways. The heated water boils into steam, builds up in pressure and explodes into the cones.

Ground ice could have performed the same geologic trick on Mars, the scientists theorize.

"The martian cones are close to outflow channels, so the cones formed in regions that were probably water- or ice-rich," said Peter Lanagan, lead author of the Geophysical Research Letters article. He said flooding most likely would have been responsible for the ground ice.

Scientists theorize that exotic forms of life could exist or have existed in pockets of frozen or liquid water near the martian surface.

Finding evidence of such microbes should prove easier in the warmer equatorial regions than the frigid polar ones, where extremely low temperatures place added strains on visiting spacecraft.

NASA's Mars Global Surveyor has taken more than 60,000 pictures since it began orbiting the red planet in September 1997.

• NASA: Mars Exploration Homepage
• Mars Planet Profile
• Ames Center for Mars Exploration
• The Mars Society
• Ames Research Center: Mars Atlases
• Malin Space Science Systems

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