Study Disputes Mars Ocean Theory

A team of geologists studying Mars has found only traces of carbonates on the planet’s surface, a finding that suggests oceans never existed on the planet.

The team, led by Phil Christensen of Arizona State University, used a thermal emission spectrometer aboard the Mars Global Surveyor spacecraft to detect the presence of carbonates, minerals that can form in large quantities in oceans.

Earth’s oceans have created spectacular carbonate or limestone cliffs. But the team found no large deposits on Mars, indicating that oceans probably never existed.

“There are no white cliffs of Dover on Mars,” said Joshua Bandfield, a staff scientist at ASU who conducted the analysis with graduate student Tim Glotz.

The trace amounts of carbonates found in Martian dust, about 1%, could have formed from interactions between the surface of Mars, the atmosphere and very small amounts of water, Bandfield said.

Scientists who argue that Mars was once covered with water have been unsuccessfully seeking carbonate deposits for decades, believing they were there but undetectable with current technology. The new finding shows that carbonate detection is possible, but that large amounts of the mineral do not exist, Christensen said.

An increasing number of scientists, including Christensen, believe Mars was not warm and wet in the past but has long been frozen and has kept its water locked up as ice.

“The discussion is leaning much more toward a glacial Mars than a tropical Mars,” he said. An icy Mars does not preclude the possibility of life, either protected in water beneath the ice or in water that melts from it.

Two NASA rovers now speeding toward Mars carry spectrometers that will be able to provide even more information on the carbonates.