Ancient Mars Ocean Theory Gains More Evidence

Evidence that an ancient ocean once covered Mars is mounting. The latest clues came in the form of photos from NASA’s Mars Reconnaissance Orbiter (MRO), which continues to circle the Red Planet.

A new study reports that the photos show what could be an ancient river delta, which could have emptied into a massive ocean that once took up one-third of Mars’ surface.

Space.com reports that Mike Lamb, a study co-author and an assistant professor of geology at the California Institute of Technology in Pasadena, explained that scientists have long though that a massive once existed on Mars. But Lamb added, “no one yet has found the smoking gun.”

While the MRO’s photos of a possible ancient Mars ocean bed are not definitive, they do help lend credibility to the theory. The study looked at high-resolution images of a portion of the Red Planet’s northern lowlands. The photos were taken by the MRO’s HiRise camera, which can distinguish features as small as 10 inches.

The area studied by Lamb and colleagues is just 620 miles from Gale Crater, where NASA’s Curiosity rover touched down almost a year ago. They looked specifically at a 39-square-mile area that is part of the Aeolis Dorsa region, according to Discovery News. The section features inverted channels often seen in river deltas over time as gravel is deposited by flowing water.

This isn’t the first time an ancient river delta has been found on Mars. However, most of them have been found inside a crater or other regions that prove ancient lakes on the Red Planet. But the new delta is the first that lends to the theory of an ancient global ocean on Mars.

Lead author Roman DiBiase, a postdoctoral scholar at Caltech, added of the discovery. “This is probably one of the most convincing pieces of evidence of a delta in an unconfined region — and a delta points to the existence of a large body of water in the northern hemisphere of Mars.”

While scientists are more convinced ancient Mars boasted a large ocean, they aren’t yet sure exactly how big it was.

[Image via DiBiase et al./Journal of Geophysical Research/2013]