Mars had a vast ocean covering its northern hemisphere. New evidence suggests that this sea Martian went through at least two “megatsunamis” that began after meteor impacts. Traces of these cataclysmic events can still be seen on the surface of the planet, and they can still contain ancient signs of life.
Giant Oceans and huge tsunamis are not the first things that come to mind when we think of Mars, but the planet has been quite different than it is today. There are about 3.4 billion years, underground explosions triggered a torrent of water that produced a cold saline ocean covering the northern plains of the planet. In some regions, it was about 1.6 kilometers deep. And it may even have been home to microbióticas lives. But the atmosphere changed Mars, and most of the water evaporated into space.
That’s the theory. This idea is based primarily on estimates of how much water Mars ever had and where it was on the surface of the planet. But few observational data exist about it . Given the absence of cuts characteristics on the coast, scientists are not sure that in fact a great ocean graced the north of the Red Planet.
But new evidence presented by scientists at the Planetary Science Institute in Tucson (PSI) in the USA, offers a more concrete proof that the ocean existed – and that he witnessed two extremely powerful megatsunamis.
Left: digital area of study model showing the two ocean shore level proposals from Mars that existed about 3.4 billion years. Right: Areas covered by tsunamis from the coast. (Images: Alexis Rodriguez)
The researcher J. Alex P. Rodriguez from PSI, together with colleagues at Cornell University recently conducted a detailed analysis of the plain surface north of Mars. Scientists have discovered traces of an ancient ocean – although he is not exactly where they expected to find.
The geological form of coastal lines of Mars and its surrounding areas indicate that two large meteorites – that hit the planet millions of years difference – generated two megatsunamis. The resulting waves that hit the earth on the planet, redrew the Martian landscape, leaving features on the surface that can be seen today.
This lobe of dark material may contain the remains of a Martian megatsunami. (Image: A. Rodriguez)
The impact of the two meteors created crater about 30 kilometers wide, and would have generated tsunami waves of up to 120 meters high. In comparison, the tsunami that hit Japan in 2011 reached a maximum height of 29 meters.
The white arrows show the range of the first tsunami. (Image: Alexis Rodriguez)
The first tsunami created channels that made the water back to the sea. These characteristics can be seen today in the form of large sedimentary deposits. The second impact occurred a few million years later (a large meteor reaches Mars every three million years). But at this stage of Martian history, the weather was already considerably cooler. The water was turning into ice, and the original coastline had retreated inland. The second left megatsunami different physical evidence, including rounded lobes of ice.
“These lobes froze on the ground as they reached their maximum extent and ice never returned to the ocean – which means that the ocean was at least partially frozen at the time,” says study co-author and scientist at Cornell Open Fairén. “Our paper provides solid evidence of the existence of frozen oceans on Mars.”
As water from the tsunami receded and turned into ice, the lobes kept their limits and forms related to the flow. This suggests that the water was saturated with salt – which, of a habitable perspective is great news. Salt retains water in liquid form, and this is important for the emergence of life.
“If there was life on Mars, these frozen lobes are a good place to look for biosignatures,” explained Fairén. . “This salt composition may have allowed the Martian oceans remain in liquid form for tens of millions of years” and Rodriguez told Gizmodo: “astrobiológicas the implications are enormous.”
To explore this idea – and to help future missions to Mars – the researchers identified regions that were flooded by the tsunami waters, especially areas where displaced sediment appears, and where salt or mineral deposits were left behind after the evaporation of Water. Those are good targets for future probes – or even human explorers – investigate.