Ancient mega-tsunamis hint at cold Martian oceans

3.4 billion years ago, a meteorite smashed into the northern plains of Mars, where an ancient ocean once stood. Its impact threw up a massive wall of liquid water that scarred the surrounding landscape with backwash channels as the water poured back into the Martian sea. A few million years later, after the Red Planet had cooled significantly, another huge chunk of space rock tore into Mars -- however, this time, the resulting tsunami was made of ice blobs that simply stuck wherever they landed rather than return to the sea.

The difference in tsunamis isn't simply a result of a cooling planet, they're evidence that Mars' early water works were capable of sustaining life, according to a newly released study from the Center of Astrobiology, Madrid.

"Our paper provides very solid evidence for the existence of very cold oceans on early Mars," principal investigator and visiting Cornell professor, Alberto Fairén said in a statement. "It is difficult to imagine Californian beaches on ancient Mars, but try to picture the Great Lakes on a particularly cold and long winter, and that could be a more accurate image of water forming seas and oceans on ancient Mars."

What's more, those icy lobes could provide key insights into whether Mars ever hosted life. "Cold, salty waters may offer a refuge for life in extreme environments, as the salts could help keep the water liquid. ... If life existed on Mars, these icy tsunami lobes are very good candidates to search for biosignatures," he continued. To that end, the researchers hope to conduct follow-up studies of the Martian terrain and identify areas of the northern plains for further investigation.