Today, Mars is a cold and dry world but many scientists believe it carried water billions of years ago. A new study on the impact craters found on the surface of Mars suggests that if the red planet harboured water, it could have experienced a “mega-tsunami” that shaped the planet. This study focuses on the identification of impact craters that impacted into the ocean and are likely to have produced the tsunami. The research analysed a meteor impact site called Lomonosov, which is 120 kilometres deep, the same height as the estimated depth of the ocean.
The impact crater strongly resembles the similar marine impact sights on Earth, and so the researchers believe that this specific impact site must have been the ground zero for the “mega-tsunami” that would have ploughed across the surface of Mars. Researchers believe that the hole in the southern lip of the crater could have been the result of the ocean roaring back from that direction.
Notably, scientists do not have definitive proof that Mars once carried oceans like Earth billions of years ago or contained water. Scientists say they need more data to confirm the Mars ocean theory but if the red planet really carried ocean, the Lomonosov crater could be the point where the planet once held an ocean.
The author of the study, Francois Costard writes in the paper, “The orientations of the associated lobate deposits — a conspicuous type of landforms called Thumbprint Terrain — suggests that if an impact event triggered the mega‐tsunami, the most likely location of the source crater is within the northern plains regions situated north of Arabia Terra.”
While earlier evidence hinted that the ocean’s shores were shaped by at least one impact in the same general area as the Lomonosov crater, this study has narrowed things down to a specific impact site.
The researchers selected 10 complex impact craters, based on their diameters, location, and geomorphic characteristics. Of those, the Late Hesperian Lomonosov crater, which is around 120 km in diameter, exhibits a unique topographic plan view asymmetry when compared to other similar‐sized and similar‐aged craters in the northern plains such as Micoud, Korolev, and Milankovic.
“We attribute its broad and shallow rim, in part, to an impact into a shallow ocean as well as its subsequent erosion from the collapsing transient water cavity,” says Costard.
The study claims that the likely marine formation of the Lomonosov crater, and the apparent agreement in its age with that of the Thumbprint Terrain unit, strongly suggests that it was the source crater of the tsunami.