An astonishing discovery on the surface of Mars suggests life may have once flourished at the bottom of a vast sea on the now barren planet.
Experts examined images taken by Nasa’s Mars Reconnaissance Orbiter (MRO) that show mineral deposits at on the bed of an ancient ocean.
They are thought to be remnants of underwater volcanoes, almost four billion years old, which would have provided ideal conditions for simple organisms to thrive.
Researchers at Nasa say the discovery yields clues to the ‘possible cradle of life‘.
Similar environments here on Earth are believed to have led to the emergence of the earliest forms of life.
The Eridania basin of southern Mars is believed to have held a sea about 3.7 billion years ago, with seafloor deposits likely resulting from underwater hydrothermal activity. This graphic, which covers an area about 530 (850 km) miles wide, shows estimated depths of water
THE ERIDANIA BASIN
Researchers estimate the ancient Eridania sea held about 50,000 cubic miles (210,000 cubic km) of water.That is as much as all other lakes and seas on ancient Mars combined and about nine times more than the combined volume of all of North America’s Great Lakes.
The mix of minerals identified from the spectrometer data, including serpentine, talc and carbonate, as well as the shape and texture of the thick bedrock layers, led to identifying possible seafloor hydrothermal deposits.
The area has lava flows that occurred after the disappearance of the sea.
The researchers cite these as evidence that this is an area of Mars’ crust with a volcanic susceptibility that also could have produced effects earlier, when the sea was present.
Researchers used the MRO to examine basins in a region called Eridania, on the southern side of the red planet.
They believe these deposits were formed by heated water from a volcanically active part of the planet’s crust.
Experts estimate hydrothermal activity created the mounds of minerals at the bottom of the seafloor 3.7 billion years ago.
In a written statement, Paul Niles of Nasa’s Johnson Space Centre, in Houston, Texas said: ‘Even if we never find evidence that there’s been life on Mars, this site can tell us about the type of environment where life may have begun on Earth.
‘Volcanic activity combined with standing water provided conditions that were likely similar to conditions that existed on Earth at about the same time, when early life was evolving here.
‘This site gives us a compelling story for a deep, long-lived sea and a deep-sea hydrothermal environment.
‘It is evocative of the deep-sea hydrothermal environments on Earth, similar to environments where life might be found on other worlds, life that doesn’t need a nice atmosphere or temperate surface, but just rocks, heat and water.’
Mars today has neither standing water nor volcanic activity.
Eridania is located at the boundary of Terrae Cimmeria and Sirenum, an ancient part of the martian crust which exhibits strong remnant magnetism
This image, taken by the Context Camera on the Mars Reconnaissance Orbiter, shows a 12 miles wide portion of the Eridania basin. Blocks of deep-basin deposits have been surrounded and partially buried by younger volcanic deposits
Undersea hydrothermal conditions on Earth at about that same time are a strong candidate for where and when life on Earth began.
Earth still has such conditions, where many forms of life thrive on chemical energy extracted from rocks, without sunlight.
But due to Earth’s active crust, our planet holds little direct geological evidence preserved from the time when life began.
The possibility of undersea hydrothermal activity inside icy moons such as Europa at Jupiter and Enceladus at Saturn feeds interest in them as destinations in the quest to find extraterrestrial life.
Observations by MRO’s Compact Reconnaissance Spectrometer for Mars (CRISM) provided the data for identifying minerals in massive deposits within Mars’ Eridania basin.
This lies in a region with some of the red planet’s most ancient exposed crust.
Experts examined images taken by Nasa’s Mars Reconnaissance Orbiter (MRO) that show mineral deposits at the bottom of an ancient ocean. They are thought to be remnants of underwater volcanoes, which would have provided ideal conditions for simple organisms
This diagram illustrates an interpretation for the origin of some deposits in the Eridania basin of southern Mars as resulting from seafloor hydrothermal activity more than three billion years ago
The researchers estimate the ancient Eridania sea held about 50,000 cubic miles (210,000 cubic km) of water.
That is as much as all other lakes and seas on ancient Mars combined and about nine times more than the combined volume of all of North America’s Great Lakes.
The mix of minerals identified from the spectrometer data, including serpentine, talc and carbonate, as well as the shape and texture of the thick bedrock layers, led to identifying possible seafloor hydrothermal deposits.
The area has lava flows that occurred after the disappearance of the sea.
The researchers cite these as evidence that this is an area of Mars’ crust with a volcanic susceptibility that also could have produced effects earlier, when the sea was present.
The new study adds to the diversity of types of wet environments for which evidence exists on Mars, including rivers, lakes, deltas, seas, hot springs, groundwater, and volcanic eruptions beneath ice.
The full findings were published in the journal Nature Communications.
