Water flow on Mars suggests ancient life on planet

Narrow ridges found in Martian craters may actually be fossilised remnants of underground cracks through which water once flowed on the red planet, a new study claims.

Water flowing beneath the surface of ancient Mars suggests life may once have been possible on the Red planet, according to a new analysis by researchers from Brown University.

The study, published in the journal Geophysical Research Letters, bolsters the idea that the subsurface environment on Mars once had an active hydrology and could be a good place to search for evidence of past life.

The study conducted by Lee Saper and Jack Mustard suggest the ridges, many of them hundreds of meters in length and a few meters wide, had been noted in previous research, but how they had formed was not known.

Saper and Mustard thought they might once have been faults and fractures that formed underground when impact events rattled the planet's crust.

Water, if present in the subsurface, would have circulated through the cracks, slowly filling them in with mineral deposits, which would have been harder than the surrounding rocks. As those surrounding rocks eroded away over millions of years, the seams of mineral-hardened material would remain in place, forming the ridges seen today.

Using high-resolution images from NASA's Mars Reconnaissance Orbiter, the researchers noted the orientations of the ridges and composition of the surrounding rocks.

The orientation data is consistent with the idea that the ridges started out as fractures formed by impact events.

Importantly, researchers also found that the ridges exist exclusively in areas where the surrounding rock is rich in iron-magnesium clay, a mineral considered to be a telltale sign that water had once been present in the rocks.

"The association with these hydrated materials suggests there was a water source available. That water would have flowed along the path of least resistance, which in this case would have been these fracture conduits," Saper said.

As that water flowed, dissolved minerals would have been slowly deposited in the conduits, in much the same way mineral deposits can build up and eventually clog drain pipes.

The results suggest the ancient Martian subsurface had flowing water and may have been a habitable environment.

"This gives us a point of observation to say there was enough fracturing and fluid flow in the crust to sustain at least a regionally viable subsurface hydrology," Saper said.