Mega-flood on Mars: remnants are there

A Journal of People report

Worcester crater in context © 

Remnants of a huge flood on Mars have been discovered, according to the European Space Agency (ESA). The space agency has captured phenomenal high-definition photos of one of the largest ‘outflow channels’ on the Red Planet, Mars.
The ESA says a combination of volcanism, tectonics, and surface collapse and subsidence led to a “massive groundwater release” from the Echus Chasma region on Mars around 3.6 to 3.4 billion years ago. These ancient mega-floods have left their mark on the features seen today.
The Kasei Valles channel system extends around 3000 km from its source region in Echus Chasma – which lies east of the bulging volcanic region Tharsis and just north of the Valles Marineris canyon system – to its sink in the vast plains of Chryse Planitia.

Sections of Kasei Valles have already been imaged by Mars Express during its 14 years at the Red Planet, but this new image, taken on May 25, 2016, captures a portion right at its mouth.
A 25 km-wide impact crater – Worcester Crater – just left to the centre of the main color image, has done its best to stand up to the erosive forces of the mega-floods.
While much of the blanket of material surrounding the crater – which was originally thrown out from inside the crater during the impact – has been eroded, the section downstream of the flood has survived. Over time this has led to the overall appearance of a streamlined island, with its stepped topography downstream perhaps suggesting variations in water levels or different flood episodes.

Topography at the mouth of Kasei Valles ©

By contrast, the debris blanket surrounding the adjacent crater has remained intact. This suggests the impact producing that crater occurred after the major flooding.
Moreover, the appearance of the debris blanket tells a story on the nature of the subsurface: in this case it points to the floodplain being rich in water or water-ice.
Indeed, the pattern is reminiscent of a ‘splash’: the debris ejected from the crater was rich in water, allowing it to flow more easily. As it slowed, the debris behind it piled up, pushing up the material at its periphery into ramparts.

Remnants of a mega-flood on Mars

Perspective view towards Worcester crater ©

The perspective view shows a close-up of this rampart feature and looks from the associated crater towards the eroded Worcester crater in the background.
The large crater at the northernmost part (right, top) of the main image does not appear to have penetrated as deep as Worcester crater and its neighbor. Indeed, it is located on a plateau at least 1 km higher than the plains below.
Nonetheless, there is a small depression in the centre of the crater, which usually implies a weaker layer – such as ice – was buried underneath at the time of the impact.
Close inspection also reveals the faint outline of the crater’s ejecta blanket including a portion that spilled over onto the plains below.

Remnants of a mega-flood on Mars

Anaglyph view at the mouth of Kasei Vallis ©

The ejecta shows an interesting grooved pattern that the other craters in this view seem to be lacking. This suggests a difference in the nature of the impact itself, perhaps either with the energy imparted during the impact, the way in which the ejecta was emplaced from the crater, or in the composition of the plateau material.
Small dendritic channels can be seen all around the plateau, which perhaps hint at the varying flood magnitudes during numerous episodes of flooding.
A number of smaller craters in the flat plains can also be found. These appear to have lighter-colored ‘tails’ pointing in the opposite direction to the flow of water coming from Kasei Valles.
These craters were formed by impacts that took place after the catastrophic flooding, their delicate tails created by winds blowing in a westwards direction ‘up’ valley. Their raised rims influence wind flow over the crater such that the dust immediately ‘behind’ the crater remains undisturbed in comparison to the surrounding, more exposed, plains.
This scene therefore preserves a record of geological activity spanning billions of years of the Red Planet’s history.
A report by Independent from the UK said:
“Mars might have been far more likely to support life than we thought, according to new research.
“Scientists have found that the planet was probably far wetter than we’d previously understood. The study, which simulated Martian meteorites to understand more about its ancient environment, suggests that our history of the planet’s surface might be entirely wrong.
“Until now, a specific mineral found in Martian meteorites was used as proof that the planet had an ancient, dry environment. But in fact it might have contained hydrogen, which may see the history of the Red Planet rewritten into one far more covered with water.
“Water is thought to be one of the central building blocks and requirements of life, and any discovery of water vastly improves the chances that the planet was inhabited.”
The “Mars far more likely to have had life than we thought, researchers find after new water discovery” headlined report by Andrew Griffin said:
“In the study, scientists created a synthetic version of the mineral known as whitlockite. They then conducted shock-compression experiments on samples of the material, simulating the conditions of being thrown on a meteorite from Mars.
“The material was then studied using X-rays to find its microscopic makeup. They found that whitlockite could become dehydrated from those shocks and form merrillite, which is commonly found in meteorites thrown to Earth from Mars but doesn’t occur here naturally.
“‘This is important for deducing how much water could have been on Mars, and whether the water was from Mars itself rather than comets or meteorites,’ said Martin Kunz, a staff scientist who worked on the studies of the samples.
“‘If even a part of merrillite had been whitlockite before, it changes the water budget of Mars dramatically,’ said Oliver Tschauner, a professor who co-led the study with Christopher Adcock.”
The March 6, 2017 report said:
“The ‘water budget’ is central to the question of whether there was ever life on Mars. Whitlockite can be dissolved in water to make phosphorus – which is required to bring about life on Earth – and the material could therefore once have been abundant on the planet.
“‘The overarching question here is about water on Mars and its early history on Mars: Had there ever been an environment that enabled a generation of life on Mars?’ Professor Tschauner said.”
The report said:
“To simulate the effect of being thrown from Mars, scientists blasted the synthetic whitlockite samples with metal plates that were fired from guns at about 1,678 miles per hour and with huge amounts of pressure. That extreme situation was required to simulate the shock of being hurled the planet’s atmosphere.
“‘You need a very severe impact to accelerate material fast enough to escape the gravitational pull of Mars,’ said Professor Tschauner.
“Even still, those conditions lasted for only 100 billionths of a second. That was only about 1 per cent as long as the actual experience would be – meaning that the conversion to merrillite would be even more potent on Mars.”
It added:
“Scientists now hope to prove that the conversion had actually taken place, by studying the meteorites on Earth and looking for traces of water.
“If they found it, it would add to the already huge evidence that Mars once flowed with water and might continue to do so today. In 2013, scientists announced that streaks on the planet’s surface appear to be caused by flowing water, and late last year researchers said that they had found a huge underground body of water ice on the planet.
“But the new research shows how the planet might have been covered in far more water than it is today. Many Martian meteorites appear to come from a period around 150 million to 586 million years ago, and are thrown onto the Earth from deep beneath the surface, meaning that they don’t necessary reflect the recent geology on the Red Planet’s surface.”

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