Study suggests warmth, flowing water on early Mars were episodic

November 17, 2014
Although the surface is now cold and desiccated, in early Mars history water formed an open-basin lake, filling the crater, forming a delta, and breaching the lower rim as water flowed to lower elevations (blue). New research suggests that warmer temperatures and water flow on ancient Mars were likely related to periodic volcanism early in the planet's history Credit: NASA/Mars Reconnaissance Orbiter Rendering by James Dickson, Brown University

Ample evidence of ancient rivers, streams, and lakes make it clear that Mars was at some point warm enough for liquid water to flow on its surface. While that may conjure up images of a tropical Martian paradise, new research published today in Nature Geoscience throws a bit of cold water on that notion.

The study, by scientists from Brown University and Israel's Weizmann Institute of Science, suggests that warmth and flow on ancient Mars were probably episodic, related to brief periods of activity that spewed tons of greenhouse-inducing into the atmosphere. The work, which combines the effect of volcanism with the latest climate models of early Mars, suggests that periods of temperatures warm enough for water to flow likely lasted for only tens or hundreds of years at a time.

With all that's been learned about Mars in recent years, the mystery of the planet's ancient water has deepened in some respects. The latest generation of climate models for early Mars suggests an atmosphere too thin to heat the planet enough for water to flow. The sun was also much dimmer billions of years ago than it is today, further complicating the picture of a warmer early Mars.

"These new that predict a cold and ice-covered world have been difficult to reconcile with the abundant evidence that water flowed across the surface to form streams and lakes," said James W. Head, professor of earth, environmental and planetary sciences at Brown University and co-author of the new paper with Weizmann's Itay Halevy. "This new analysis provides a mechanism for episodic periods of heating and melting of snow and ice that could have each lasted decades to centuries."

Halevy and Head explored the idea that heating may have been linked to periodic volcanism. Many of the geological features that suggest water flow date to around 3.7 billion years ago, a time when massive volcanoes are thought to have been active and huge lava outpourings occurred. On Earth, however, widespread volcanism often leads to cooling rather than warming. Sulfuric acid particles and thick ash reflect the sun's rays, and that can lower temperatures. But Head and Halevy thought the effects of sulfur in Mars' dusty atmosphere might have been different.

To find out, the researchers created a model of how sulfuric acid might react with the widespread dust in the Martian atmosphere. The work suggests that those sulfuric acid particles would have glommed onto dust particles, which would reduce their ability to reflect the sun's rays. Meanwhile sulfur dioxide gas would produce a modest greenhouse effect—just enough to warm the Martian equatorial region so that water could flow.

Head has been doing fieldwork for years in Antarctica and thinks the climate on early Mars may have been very similar to that of the cold, desert-like McMurdo Dry Valleys.

"The average yearly temperature in the Antarctic Dry Valleys is way below freezing, but peak summer daytime temperatures can exceed the melting point of water, forming transient streams, which then refreeze," Head said. "In a similar manner, we find that volcanism can bring the temperature on early Mars above the melting point for decades to centuries, causing episodic periods of stream and lake formation."

But as that early active volcanism on Mars ceased, so did the possibility of warmer temperatures and flowing water.

Head said the research may offer new clues about where the fossilized remnants of life might be found on Mars, if it ever existed.

"Life in Antarctica, in the form of algal mats, is very resistant to extremely cold and dry conditions and simply waits for the episodic infusion of water to 'bloom' and develop," he said. "Thus, the ancient and currently dry and barren river and lake floors on Mars may harbor the remnants of similar primitive life, if it ever occurred on Mars."

Explore further: Unusual greenhouse gases may have raised ancient Martian temperature

More information: Nature Geoscience, dx.doi.org/10.1038/ngeo2293

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Modernmystic
not rated yet Nov 17, 2014
Interesting. If it was too episodic we may not find evidence of life. I'm assuming it was stable for at least a few hundred million years at a time, and that should be sufficient for life to form...but that's just me assuming.
LariAnn
1 / 5 (8) Nov 17, 2014
For those who are convinced that liquid water has not been seen on Mars for millions or billions of years, see the hi-res version of the NASA photo here: http://photojourn...PIA16550 - the reflection of the rocks is not a reflection typical of dry or frozen sand or dirt. Looks very suspicious to me, especially because this photo was taken by the Curiosity rover at close range. The rover could have sampled whatever is causing the water-like reflection and determined once and for all what is there. However, there is no indication of any interest in anything in this area except for the rocks!
hemitite
not rated yet Nov 17, 2014
Not being able to access this article, I don't know if these guys took the effect on Mars's history of extreme axial tilting on that planet's climate might have had in producing these warmer periods. As for life, my guess is that, if it arose on Mars, it would be in some sort of hot springs environment, probably sub surface.
Shootist
1 / 5 (1) Nov 17, 2014
Boys didn't mention that every time a 300 km+ diameter basin was created the heat pulse would vaporize and liquefy much of the planetary surface ice.

http://www.lpi.us...3070.pdf
baudrunner
1 / 5 (2) Nov 17, 2014
I think that future Mars colonists will have a devil of a time getting around on foot in a lot of places on Mars. They will run the risk of slipping on the ice and rupturing their environment suits. Naturally, they will land close to where water sources are perceived to be.

Could this be a frozen lake of crystal clear water? https://www.faceb...;theater

This is the most tantalizing HiRISE image I've seen.
baudrunner
not rated yet Nov 17, 2014
It's unfortunate that so far the Rovers have been sent to areas that represent the least amount of risk, sort of like landing a rover in the middle of a salt flat to study Earth. I'm hoping that future landing strategies will accept some risk, in order to study the more intriguing features that have us puzzled and conjecturing as to their true nature.

The ExoMars expedition, a joint venture between ESA and Russia's Roscosmos space agency projected for 2018, has rejected most of the planet's surface as being unsuitable for landing a rover http://www.scienc...rs-2018/
Shootist
not rated yet Nov 17, 2014
Interesting. If it was too episodic we may not find evidence of life. I'm assuming it was stable for at least a few hundred million years at a time, and that should be sufficient for life to form...but that's just me assuming.


Recall that there is no existing surface on Mars older than 4.1Gya. So, it remains unclear what happened during the 400 million years between planetary formation and the Late Heavy Bombardment, which (probably) quenched the Martian dynamo and hastened the removal of the Martian atmosphere. Also an Ice World does not rule out life, only liquid surface water.
Torbjorn_Larsson_OM
5 / 5 (6) Nov 18, 2014
If you look at McMurdo Dry Velleys, they do have saline lakes like the liquid water Phoenix found on its landing legs.

@Mm: If life emerged in hydrothermal systems (volcanic or impact generated) as here, it could be found in crustal refugia. Should the ground water be fully iced over, there is still liquid surfaces on the ice. Modern bacteria suffice a liquid layer 3 molecules thick...

@LariAnn, baudrunner: Anecdotes, not data.
Torbjorn_Larsson_OM
5 / 5 (5) Nov 18, 2014
@Shootist: Actually, Curiosity has an average age of Gale's oldest surface rocks at 4.2 billion [ http://www.planet...ing.html ]. And we do have older samples of 4.4 billion years, as old as the oldest Earth material, but like it it will be a hard slog to predict early Mars.

"Prof Humayan explained: "The crust of Mars must have differentiated really quickly, rather than gradually over time. There was a big volcanic episode all over the surface, which then crusted up, and after that the volcanism dropped dramatically." [ http://www.bbc.co...25016479 ]
Selena
Nov 18, 2014
This comment has been removed by a moderator.
cantdrive85
1 / 5 (5) Nov 18, 2014
Where is this evidence of flowing water? Oh, right. There is none at all...
tadchem
5 / 5 (5) Nov 18, 2014
Where is this evidence of flowing water? Oh, right. There is none at all...

Note the delta formed where the channel enters the crater. Deltas are formed where sediment-laden fluids slow down and deposit their sediment.
Modernmystic
not rated yet Nov 18, 2014
Interesting. If it was too episodic we may not find evidence of life. I'm assuming it was stable for at least a few hundred million years at a time, and that should be sufficient for life to form...but that's just me assuming.


Recall that there is no existing surface on Mars older than 4.1Gya. So, it remains unclear what happened during the 400 million years between planetary formation and the Late Heavy Bombardment, which (probably) quenched the Martian dynamo and hastened the removal of the Martian atmosphere. Also an Ice World does not rule out life, only liquid surface water.


I've yet to hear a theory of bio-genesis that doesn't include copious amounts of surface water. I'd be very happy to see any studies or theories to the contrary.

Remember, it's not enough that life might exist now, or might have existed at some point...it's that life had to BEGIN at some point as well.
Shootist
not rated yet Nov 18, 2014
@Shootist: Actually, Curiosity has an average age of Gale's oldest surface rocks at 4.2 billion


http://www.planet...ing.html

Gale craters incises the Utopia and Hellas debris field and thus is younger than either.

Moon has the oldest preserved crust (4.1Gy) Mars the youngest. http://www.scienc...14003215

Modernmystic
not rated yet Nov 18, 2014
Actually I'll amend that. Europa has copious amounts of water, but technically couldn't be called "surface water", and one can easily see how life might arise there with tidal heating and chemosynthesis....
baudrunner
not rated yet Nov 18, 2014
I've yet to hear a theory of bio-genesis that doesn't include copious amounts of surface water. I'd be very happy to see any studies or theories to the contrary.
I think we should abandon the idea that there was ever indigenous life on Mars. The conditions probably existed to sustain life for a period of time, but not long enough for bio-genesis to ever have occurred.
TheGhostofOtto1923
1 / 5 (1) Nov 22, 2014
Just read a new book by Greg Bear - War Dogs. Its about hostile alien visitors on mars with neutral colonists caught in the crossfire.

Mr Bear describes one colony mined into the remains of a huge nickel iron meteorite, with a subterranean river running below it which the colonists used to generate hydro power.

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