Proposed Martian Ocean Shorelines 3.4 Billion Years BP (credit: NASA Ames Research Center, CA)
In a remarkable discovery, evidence is mounting that a meteor hit Mars releasing a mega-tsunami that flooded the northern region of the planet early in its history. Investigators at the Ames Research Center have observed what appears to be the shorelines of an ancient ocean altered by wave action. The existence of an ancient ocean on Mars had been long predicted but a shoreline had been lacking to confirm its existence.
According to NASA satellite data, 3.8 billion years ago the planet was a cold and dry desert with large subsurface aquifers covered by permafrost. These underground resevoirs held most of the water on Mars. The new analysis suggests that several of these aquifers catastrophically ruptured, carving channels that flooded the northern plains of Mars, forming an ocean. The NASA analysis shows that the "shorelines exist below the present surface and were modified and buried by two mega-tsunami events. The research documents giant waves may have formed as a result of (meteor) impacts slamming into Mars’ ocean."
The detective work utilized visible and thermal photographic images, combined with digital topography gathered by the Mars Odyssey, Reconnaissance Orbiter (MRO), and Global Surveyor missions. The tsunamis resulting from the meteor impacts could have produced waves that ranged from nearly 100 to possibly 400 feet high. A visualization of the data has been animated here.
The published details of the Martian tsunami discoveries are available here.