Mars satellites show remains of massive tsunamis that ravaged Red Planet

Two asteroid strikes had huge consequences

Scientists think they have spotted the remains of two huge tsunamis on Mars caused by asteroids striking the planet back when it still had water.

In a paper published in Nature Scientific Reports, the boffins say pictures from the imaging and radar satellites orbiting Mars show the effects of two separate asteroid strikes on what was once a vast ocean in the northern hemisphere of the Red Planet, 3.4 billion years ago.

"For more than a quarter century, failure to identify shoreline features consistently distributed along a constant elevation has been regarded as inconsistent with the hypothesis that a vast ocean existed on Mars approximately 3.4 billion years ago," said lead author J. Alexis Palmero Rodriguez from the Planetary Science Institute.

"Our discovery offers a simple solution to this problem; widespread tsunami deposits distributed within a wide range of elevations likely characterize the shorelines of early Martian oceans."

The first planetary strike saw an asteroid blast a 30‑km crater in the Martian surface and would have generated waves of water around 400 feet high that would have traveled hundreds of miles inland, depositing boulders over the landscape and leaving deep channels cut into the surface as the water flowed back into the sea.

The Martian shore

Shoreline development asteroid-style

The second strike occurred a few million years later, when the sea was much colder, the theory goes. This tsunami was smaller, as the sea was more icy slush than liquid, but left behind characteristic flow patterns of slush over the Martian surface.

"We have already identified some areas inundated by the tsunamis where the ponded water appears to have emplaced lacustrine sediments, including evaporites. As a follow-up investigation we plan to characterize these terrains and assess their potential for future robotic or human in-situ exploration," Rodriguez said.

The idea is that these areas are likely to have the highest concentrations of water remains, so when the next rovers get sent to Mars, such as NASA's proposed Curiosity 2.0 mission in 2020, they can drill down and have a better chance of finding water, or even signs of ancient life. ®

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