Scientists discovered crater linked to tsunamis

Houston : Scientists have discovered a crater linked to tsunamis that swept part of ancient Mars. They have found an asteroid at 150-m-high waves when it dived into the ocean, which might have existed on northern Mars three billion years ago. The Lomonosov crater in the planet’s northern plain fits the same, according to the source of tsunami deposits identified on the surface. All this was outlined at 48th Lunar and Planetary Science Conference.

Now the idea has lost some of its currency over years, because scientists believe an ocean might have once be filled the lowland region that captures the Red Planet’s Northerly Latitudes. Increasing evidences of tsunami waves being washed over the boundary help to strengthen hypothesis.

François Costard, Steve Clifford and colleagues discovered and mapped the distribution of sediment that originated in northern plains and flowed onto a ancient shoreline to the south.

"We found typical tsunami deposits along the dichotomy between the northern hemisphere and southern hemisphere of Mars," Dr Costard, from Université Paris-Sud and CNRS, told BBC News.

"It supports that there was, at that time, a northern ocean."

Climbing high

Another type of feature discovered on the dichotomy boundary is a lobate flow deposit. Dr. Clifford from the Lunar and Planetary Institute in Houston, explained this.

"These lobate deposits propagate uphill from the northern plains and do so in close association with a potential palaeo-shoreline. The predictions of the numerical modelling that François and his colleagues have done provide a very persuasive case for an ocean at this time," he told BBC News.

"There's also a second set ezof landforms that we see along the coastline called thumbprint terrain.... the reflection of the tsunami waves from the coast and their interaction with a second set of tsunami waves, predicted by the numerical modelling, would have resulted in sediment deposition that's very similar to what we actually observe on Mars."

This terrain has previously been interpreted as having been caused by mud flows, mud volcanoes, or glaciers.

"If we do have this evidence of a tsunami having occurred back three billion years ago, there must have been an ocean present in the northern plains," said Steve Clifford.

"That's the key point here, it indicates that there was a substantial amount of water in residence on the Martian surface at this time and that has likely implications for the total inventory of water on Mars."

Two waves

The scientists and researchers have identified a 120km wide bowl called Lomonosov, after the 18th Century Russian polymath Mikhail Vasilyevich Lomonosov. Perhaps this feature is disregarded today.

Two successive waves were formed during the event, says François Costard.

"It was a really large-scale, high speed tsunami. At the very beginning, a crater of 70km in diameter was created by the impact. This expelled a huge volume of water, with wave propagation at 60m/second," he explained.

"The initial wave was about 300m in height. After just a few hours, that tsunami wave reached the palaeo-shoreline located at a few hundred km from the impact crater."

"Finally... due to the Martian ocean filling in that crater, which produced a kind of rebound, there was a second wave propagation," Dr Costard added.

It is believed that if there was an ocean on Mars three billion years ago, it could have m,ade the red planet a more reliable place for life.

"It's very hard to conceive of any other process other than a tsunami that could have emplaced these lobate deposits along the dichotomy boundary," Steve Clifford told BBC News.

"There is ambiguity in all the various lines of evidence that have been cited regarding whether Mars is water-rich or water-poor. But the morphologic evidence that's been presented here is a very persuasive case for a water-rich planet."

While some other teams have reported evidence of tsunamis on Mars, but none has linked the events to particular impact crater.