According to a news release from the Imperial College London, an ancient fresh water lake on the Red Planet could have sustained life. Researchers have discovered proof that there was once a primordial lake on the Red Planet that may have been able to support life.

Researchers from the NASA’s Mars Science Laboratory Curiosity rover mission have examined a set of sedimentary rock outcrops at a site called Yellowknife Bay in Gale Crater, in close proximity to the Martian equator. These mudstones have shown that Gale Crater maintained at least one lake around 3.6 billion years ago.

The researchers think that the ancient lake may have survived for tens if not hundreds of thousands of years.

Their work revealed that the lake was tranquil and likely contained fresh water with key biological ingredients like carbon, hydrogen, oxygen, nitrogen and sulphur. This type of lake would offer excellent conditions for simple microbial life like chemolithoautotrophs to live in.

On Earth, chemolithoautotrophs are typically discovered in caves and near hydrothermal vents. The microbes wear down rocks and mineral for energy.

Mudstones typically develop in tranquil environments. They are made by extremely fine sediment grains coming to rest layer-by-layer on each other, in still water.

“It is important to note that we have not found signs of ancient life on Mars,” posited co-author Sanjeev Gupta, a member of the MSL mission from the Department of Earth Science and Engineering at Imperial College London, in a statement. “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. This is 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 added. “The next phase of the mission, where we will be exploring more rocky outcrops on the crater’s surface, could hold the key whether life did exist on the red planet.”

In earlier work, Gupta and the MSL team have discovered proof of water on Mars’ surface in other rocks like conglomerates. However, the new findings offer the best evidence yet that the Red Planet could have been habitable enough to sustain life.

The study’s findings are published in greater detail in the journal Science.