A mega-tsunami on Mars may have been caused by an asteroid strike – similar to the one that wiped out land dinosaurs on Earth 66 million years ago – in a shallow ocean region, a new study suggests.
Past research proposed an asteroid or comet impact within an ocean in the Martian northern lowlands may have caused a mega-tsunami approximately 3.4 billion years ago.
However, before the new study the location of the crater caused by the impact was unclear.
Alexis Rodriguez at the Planetary Science Institute, Tucson, America, and colleagues, analysed maps of the red planet’s surface, created by combining images from previous missions to the planet.
They identified an impact crater that could have caused the mega- tsunami – a giant wave.
The crater – which they have named Pohl – is 110 kilometres in diameter.
It is located within an area of the northern lowlands that previous studies have suggested may have been covered by an ocean, in a region some 120 metres below its proposed sea level.
According to the researchers, based on Pohl’s position it may have formed around 3.4 billion years ago, based on its position above and below rocks previously dated to this time.
The authors simulated asteroid and comet collisions with this region to test what type of impact could have created Pohl, and whether this could have led to a mega-tsunami.
Simulations that formed craters with similar dimensions to Pohl were caused by either a nine kilometre asteroid encountering strong ground resistance – releasing 13 million megatons of TNT energy – or a three kilometre asteroid encountering weak ground resistance – releasing 0.5 million megatons of TNT energy.
The amount of energy released by the most powerful nuclear bomb ever tested was approximately 57 megatons of TNT energy.
Both of the impacts that were simulated formed craters measuring 110 kilometres in diameter and generated mega-tsunamis that reached as far as 1,500 kilometres from the centre of the impact site.
Analysis of the mega-tsunami caused by the three-kilometre asteroid impact, suggested the tsunami may have measured up to approximately 250 metres tall on land.
According to the researchers, the aftermath of the proposed Pohl impact may have had similarities with the Chicxulub impact on Earth.
Writing in the Scientific Reports journal, the researchers say: “The site’s location along a highland-facing lobe aligned to erosional grooves supports a mega-tsunami origin.”
They add: “Our findings allow that rocks and soil salts at the landing site are of marine origin, inviting the scientific reconsideration of information gathered from the first in-situ measurements on Mars.”