Researchers said on Monday they have found evidence that there was once an ancient fresh water lake on Mars that may have been able to support life.

A team of researchers from the U.S. Curiosity rover mission, analyzed a set of sedimentary rock outcrops at a site named Yellowknife Bay in Gale Crater, where the six-wheeled science laboratory landed in August 2012.

These mudstones, fine-grained sediment that can form over time from clay or mud, revealed that Gale Crater, a 150 km wide impact basin with a mountain at its center, sustained at least one lake around 3.6 billion years ago. The researchers believed that the lake may have lasted for tens if not hundreds of thousands of years.

The team said their analysis showed that the lake was calm and likely had fresh water, containing key biological elements such as carbon, hydrogen, oxygen, nitrogen and sulphur. Theoretically, such a lake would provide perfect conditions for simple microbial life such as chemolithoautotrophs to thrive in.

On Earth, chemolithoautotrophs are commonly found in caves and around hydrothermal vents. The microbes break down rocks and minerals for energy.

The findings were published in the U.S. journal Science and presented at the American Geophysical Union's fall meeting in San Francisco on Monday.

"It is important to note that we have not found signs of ancient life on Mars. What we have found is that Gale Crater was able to sustain a lake on its surface at least once in its ancient past that may have been favorable for microbial life, billions of years ago," Professor Sanjeev Gupta, a member of the Curiosity mission from the Imperial College London and a co-author of the paper, said in a statement.

Gupta described the new research as "a huge positive step" for the exploration of Mars.

"It is exciting to think that billions of years ago, ancient microbial life may have existed in the lake's calm waters, converting a rich array of elements into energy," Gupta said.

In previous studies, scientists found evidence of water on Mars ' surface in other rocks such as conglomerates. However, the new research provides the strongest evidence yet that Mars could have been habitable enough for life to take hold.

The team analyzed the geology and chemistry of the mudstones by drilling into the rock using the Curiosity rover, which is remotely operated by researchers on Earth.

The researchers said the next step is to use the rover to explore Gale Crater for further evidence of ancient lakes or other habitable environments in the thick pile of sedimentary rocks scattered across the crater's surface.

Source: Xinhuanet