Traces of Ancient Mega-Tsunamis Discovered on Mars

[LongTomH]

This is all over the net today; From Gizmodo Traces of Ancient Mega-Tsunamis Discovered on Mars:

Mars once featured a vast ocean that covered its northern hemisphere. New evidence suggests this Martian sea experienced at least two “mega-tsunamis” that were triggered by meteor impacts. Traces of these cataclysmic events can still be seen on the Martian surface, and they could still contain traces of ancient life.

Giant oceans and massive tsunamis aren’t the first things that come to mind when we think of Mars, but this planet used to be quite different. About 3.4 billion years ago, groundwater outbursts unleashed a torrent of water that produced a cold and salty ocean that covered the planet’s northern lowlands. In some regions it was about a mile deep. It may have even fostered microbial life. Eventually, however, the climate changed on Mars, and most of the water evaporated into space.

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PSI researcher J. Alex P. Rodriguez and his colleagues from Cornell University recently conducted a detailed surface analysis of the northern plains of Mars. They discovered traces of a former ocean—though not exactly where one might expect. The geologic shape of Mars’ ancient shorelines and its immediate inland areas indicates that two large meteorites—striking the planet millions of years apart—triggered a pair of mega-tsunamis. The resulting waves, which moved several hundreds of miles inland, reshaped the Martian landscape, leaving surface features that are still visible today.

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As the receding tsunami water turned to ice, the lobes maintained their boundaries and flow-related shapes. This suggests that the water was saturated with salt—which, from a habitability perspective, is very good news. Salt keeps water in a liquid state, and that’s important for the emergence of life.

“If life existed on Mars, these icy tsunami lobes are very good candidates to search for biosignatures,” said Fairén. “This salty composition may have allowed Martians ocean to remain in liquid form for as long as tens of millions of years.”

“The astrobiological implications are enormous,” Rodriguez told Gizmodo.

More from The Planetary Science Institute: Detection of Possible Mega-Tsunami Deposits on Mars Revives Ancient Ocean Hypothesis:

“For more than a quarter century, failure to identify shoreline features consistently distributed along a constant elevation has been regarded as inconsistent with the hypothesis that a vast ocean existed on Mars approximately 3.4 billion years ago. Our discovery offers a simple solution to this problem; widespread tsunami deposits distributed within a wide range of elevations likely characterize the shorelines of early Martian oceans,” Rodriguez said.

From BBC News: Evidence of ancient tsunamis on Mars

A view (right) of a boulder-rich surface (yellow bars are 10m) deposited by the older tsunami, and then eroded (left) by channels produced as the tsunami water returned to the ocean elevation level

These ancient shoreline features should be prime spots for future robotic and human explorers.

[Ichingcarpenter]

1. And another hit Earth at the same time?

New signs of monster asteroid that hit Earth 3.5 billion years ago

http://www.cbsnews.com/news/new-signs-of-monster-asteroid-that-hit-earth-3-5-billion-years-ago/

Well almost the same time in geologic time scale.