A pretty cool result came out of Cornell University this week, showing that Mars was struck by a pair of ancient asteroids that caused massive tsunamis. Not only is it the first evidence of a tsunami event on another world, but it proves that Mars once had a large ocean.
The study looked at ancient shorelines between the lowlands and highlands of Mars, where the ocean-land boundary would have been. Two massive impacts, a few million years apart, extended the shorelines and caused turmoil with the Martian climate at the time.
“About 3.4 billion years ago, a big meteorite impact triggered the first tsunami wave. This wave was composed of liquid water. It formed widespread backwash channels to carry the water back to the ocean,” said Alberto Fairén, Cornell visiting scientist in astronomy and principal investigator at the Center of Astrobiology, Madrid. “Our paper provides very solid evidence for the existence of very cold oceans on early Mars. 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.”
Although the water would have been cold, with Mars being further from the Sun, it could have remained liquid if it was salty, which the observations seem to suggest. If life was present on ancient Mars, the salty liquid water would be a good place to find it. With these ancient shorelines, the researchers have found a good place to look for ancient biosignatures of Martian life, if it existed.
“We have already identified some areas inundated by the tsunamis where the ponded water appears to have emplaced lacustrine sediments, including evaporites,” said lead author Alexis Rodriguez of the Planetary Science Institute. “As a follow-up investigation we plan to characterize these terrains and assess their potential for future robotic or human in-situ exploration.”
It’s a big week for Mars!