Lava, not water, said cause of Mars beds

A U.S. researcher says large, river-like channels seen on Mars were created not by water but by massive, fast-moving lava flows of a type we don't see on Earth.

Geoscience Professor David Leverington at Texas Tech University says what we interpret as the largest ancient riverbeds on Mars most likely were created by low-viscosity lava flows that ravaged the planet's surface.

Leverington says recent high-resolution photographs and mineralogical data support his theory for why lava is a much more likely culprit for creating the largest class of the outflow channels and canyons, some of which stretch up to 1,800 miles.

The channels superficially resemble channels on Earth formed by floods from giant glacial lakes, he says, but the Martian canyons do not feature obvious river deposits and don't terminate in delta-like, sediment-laden mouths, such as at the end of the Mississippi River.

Instead, he says, they fade into vast plains composed of volcanic basalt.

"We see abundant evidence for past eruptions of lava at the heads of these large systems, for flows along these systems and for extraordinarily large volumes of lava at the mouths of these systems," he said Thursday in a university release, noting the characteristics are very similar to what is seen at volcanic channels on the moon and Venus.

"There's really no known process for the rapid eruption of large amounts of water from aquifers to form channels that are thousands of miles long," he said. "We do have evidence of this happening through past volcanic processes on the moon and Venus."