Did alien life flourish in ancient Martian marshlands? Crater on Mars was much wetter and warmer 3.8 billion years ago

The images beamed back to Earth by spacecraft and rovers have revealed Mars to be a cold, dusty and barren landscape.

But evidence is building to suggest the planet looked very different around 3.8 billion years ago, and might have been a much more welcoming place for life.

A new study suggests there may be an extensive spread of carbonates beneath the surface of the red planet, which point to a warmer and wetter environment in the planet's past.

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Aeolian bed forms overlie ancient layered, ridged carbonate-rich outcrop exposed in the central pit of Lucaya crater, northwest Huygens basin, Mars. The image was taken by the High Resolution Imaging Science Experiment (HiRISE) instrument aboard the Mars Reconnaissance Orbiter 

Researchers from the Georgia Institute of Technology and the Search for Extra-Terrestrial Life Institute  (Seti) found widespread buried deposits of iron and calcium-rich Martian carbonates.

It suggests that the planet had a much warmer and wetter climate that may have seen the surface covered in a kind of marshland. 

'Identification of these ancient carbonates and clays on Mars represents a window into history when the climate on Mars was very different from the cold and dry desert of today,' said Dr Janice Bishop, from the Seti Institute, who was one of the researchers involved in the study.

There is a growing consensus among scientists that water once did flow on Mars and may even have been relatively widespread, following a series of recent discoveries, although it remains contentious.

If water was present on Mars, scientists think the bedrock of the planet would be full of carbonates and clays, evidence the planet was once a habitable environment with liquid water.

But until now few of these deposits have been found on the Martian surface.

Mars is famous for being covered in a dry and cold landscape, which is not the ideal place for life to blossom. But evidence is building to suggest the planet looked very different around 4 billion years ago, and might have been a more welcoming place for life

Ancient layered clay-bearing bedrock (top left) and carbonate bedrock (bottom right) are shown exposed in the central uplift of an unnamed crater approximately 42 kilometers in diameter in eastern Hesperia Planum,on Mars. Researchers had struggled in the past to find physical evidence for this carbonate-rich bedrock

Researchers had struggled in the past to find physical evidence for this carbonate-rich bedrock, which they believe would have formed when carbon dioxide in the planet's early atmosphere was trapped in ancient surface waters.

But the new study has highlighted evidence of carbonate-bearing rocks in multiple sites across Mars, including Lucaya crater, where carbonates and clays 3.8 billion years old were buried by as much as 3 miles (5 km) of lava and a hard kind of rock called caprock.

They focussed their search in the Mars' Huygens basin, an impact crater on Mars named in honour of the Dutch astronomer Christiaan Huygens.

The feature is an ideal site to investigate carbonates because multiple impact craters and troughs have exposed ancient, subsurface materials where carbonates can be detected across a broad region.

According to Professor James Wray, lead author of the study, 'outcrops in the 450-km wide Huygens basin contain both clay minerals and iron- or calcium-rich carbonate-bearing rocks.'

The researchers identified the carbonates on the planet using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), which is on the Mars Reconnaissance Orbiter.

The researchers identified the carbonates on the planet using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), which is on the Mars Reconnaissance Orbiter (artist's impression pictured)

Our neighbouring planet Mars could have been covered in vast salty oceans (artist's impression pictured). According to a study published last week, a pair of meteor impacts several million years apart caused two mega tsunamis on the red planet - providing more evidence early Mars could have supported life

The space race to Mars is heating up – and now, Lockheed Martin is getting involved. The military firm has unveiled plans to create a manned space laboratory that will orbit the planet by 2028. It says it will use existing technologies, such as the Orion deep-space capsule, to speed up development of the outpost

The instrument collects the spectral fingerprints of carbonates and other minerals through vibrational transitions of the molecules in their crystal structure that produce infrared emission.

The extent of the global distribution of Martian carbonates is not fully resolved yet, and the early climate on the red planet is still subject of debate, the researchers add.

The identified regions of Mars could be a good place to look for evidence that life once existed in future missions to the red planet, the researchers said. 

This comes a few days after a new study showed early Mars was hit with two mega tsunamis, with the first 3.4 billion years ago.

MARS WAS PLAGUED BY MEGA-TSUNAMIS

It has long been thought Mars was home to a vast ocean 3.4 billion years ago.

But the evidence for shorelines did not support the theory, since it showed the shores were elevated and distributed rather than distributed consistently. 

But a team based in the US used advanced imaging techniques combined with numerical simulations to demonstrate two separate meteorite impacts caused tsunamis reaching as high as 394 feet (120 metre) on the planet.

This will have created the elevated shorelines, the researchers say. 

The findings may now provide new clues for where may be the best place to search for signs of life that may have existed, or perhaps even still survives, on Mars. 

Scientists have found evidence for two ancient mega-tsunamis that swept across Mars billions of years ago and reshaped the landscape. Colour-coded digital elevation model of the study area (pictured) show two proposed shoreline levels of an early Mars ocean that existed approximately 3.4 billion years ago