A spot on Mars called Nili Fossae that is rich in clay mineral-rich rocks could be a prime spot to search for the fossilized remains of Martian life that may have existed 4 billion years ago, a new study suggests.
In the study, scientists used an instrument on NASA's Mars Reconnaissance Orbiter to study clay-carbonate rocks on the Martian surface leftover from ancient red planet era known as the Noachian period.
The study does not offer actual evidence of past life; rather, it suggests a place that might have been habitable.
"We suggest that the associated hydrothermal activity would have provided sufficient energy for biological activity on early Mars at Nili Fossae," said study lead author Adrian Brown, a scientist at the Search for Extraterrestrial Intelligence Institute (SETI) in Mountain View, Calif., in a statement.
The study's findings will be detailed in an upcoming issue of the journal Earth and Planetary Science Letters.
Scientists have not yet discovered proof of life on Mars, or anywhere in the universe beyond Earth, though they are getting closer to knowing where to look and how to recognize the signs of life if they are present.
Brown and his colleagues studied the hydrothermal formation of clay-carbonate rocks in the Nili Fossae region on Mars. Their results suggest that these carbonate-bearing rocks share similarities with traces of life and biological markers on early Earth – particularly in a region of Western Australia.
The Nili Fossae are valleys that have cut into the ancient crust of Mars, exposing clay minerals.
The Mars terrain in this region shares many traits with Australia's East Pilbara region, which has preserved evidence of ancient Earth life beneath the soil, they said.
"In the article, we discuss the potential of the Archean volcanic of the East Pilbara region of Western Australia as an analog for the Noachian Nili Fossae on Mars," Brown said. "They indicate that biomarkers or evidence of living organisms, if produced at Nili, could have been preserved, as they have been in the North Pole Dome region of the Pilbara craton."
The Nili Fossae region was seen as an ideal area to investigate the potential habitability of early Mars. At one point, it was in the running as one of seven candidate landing sites for NASA's upcoming Mars Science Laboratory rover mission.
Since then, NASA scientists have whittled the candidate rover landing targets to four locations on Mars known as Mawrth Vallis, Gale crater, Holden crater and Eberswalde crater.
Brown and his team of researchers used the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument onboard NASA's Mars Reconnaissance Orbiter. Crism studied the ancient rocks with infrared light.