The formation of an Idaho canyon thousands of years ago has given scientists a clearer picture of how water sculpted the surface of Mars.
The chasm in the western United States has a shape once thought to be characteristic of slower, sustained groundwater flows, but new research suggests that was carved by ancient torrential floods.
Comparable canyons on Mars may share a similarly violent history, scientists at the University of California at Berkeley say.
A plentitude of Martian canyons—once thought to be evidence of gradual erosion—supported the theory that rain never fell on the red planet, said lead author Michael Lamb.
"That's probably not true," he said. "You need a lot of water to carve these canyons."
A separate study analyzed silica deposits recently dug up by NASA's Spirit rover. The deposits suggest Yellowstone-like hot springs have operated on Mars's surface, scientists note.
Both new studies—appearing in this week's journal Science—suggest Mars was wetter than previously believed, with water falling from above and shooting out of the ground as geysers, hot springs, and thermal vents.
Such active sites may be ideal for finding signs of past life, experts say. (See full coverage of the search for life on Mars.)
Massive Floods
Idaho's Box Canyon is an "amphitheater-headed" canyon, because its valley abruptly stops at its headwall. These types of chasms are thought to develop as groundwater seeps through the steep headwall.
Researchers have shown that this process works in loose, sandy material.
But the same effect hasn't been replicated in hard, basaltic rock, such as that of Box Canyon and many of the canyons on Mars.
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