Mars volcanic deposit tells of warm and wet environment

Oct 31, 2010
Volcanic deposits on Mars may preserve evidence of one of the planet’s most recent habitable microenvironments. The deposits, shown in white (arrows), are located in Nili Patera, a degraded volcanic cone in Syrtis Major of equatorial Mars. Credit: J.R. Skok / Brown University

(PhysOrg.com) -- Roughly 3.5 billion years ago, the first epoch on Mars ended. The climate on the red planet then shifted dramatically from a relatively warm, wet period to one that was arid and cold. Yet there was at least one outpost that scientists think bucked the trend.

A team led by planetary geologists at Brown University has discovered mounds of a mineral deposited on a volcanic cone less than 3.5 billion years ago that speak of a warm and wet past and may preserve evidence of one of the most recent habitable microenvironments on Mars.

Observations by NASA's enabled researchers to identify the mineral as hydrated silica, a dead ringer that water was present at some time. That fact and the mounds' location on the flanks of a volcanic cone provide the best evidence yet found on Mars for an intact deposit from a hydrothermal environment — a steam fumarole or a hot spring. Such environments may have provided habitats for some of Earth's earliest life forms.

"The heat and water required to create this deposit probably made this a habitable zone," said J.R. Skok, a graduate student at Brown and lead author of the paper in Nature Geoscience. "If life did exist there, this would be a promising spot where it would have been entombed — a microbial mortuary, so to speak."

No studies have determined whether Mars has ever supported life, but this finding adds to accumulating evidence that at some times and in some places, Mars hosted favorable environments for microbial life. The deposit is located in the sprawling, flat volcanic zone known as Syrtis Major and was believed to have been left during the early Hesperian period, when most of Mars was already turning chilly and arid.

"Mars is just drying out," Skok said, "and this is one last hospitable spot in a cooling, drying Mars."

Concentrations of hydrated silica have been identified on Mars previously, including a nearly pure patch found by NASA's Mars Exploration Rover Spirit in 2007. However, this is the first found in an intact setting that clearly signals the mineral's origin.

"You have spectacular context for this deposit," Skok said. "It's right on the flank of a volcano. The setting remains essentially the same as it was when the silica was deposited."

The small, degraded cone rises about 100 meters from the floor of a shallow bowl named Nili Patera. The patera spans about 50 kilometers (30 miles) in Syrtis Major of equatorial Mars. Before the cone formed, free-flowing lava blanketed nearby plains. The collapse of an underground magma chamber from which lava had emanated created the bowl. Subsequent lava flows, still with a runny texture, coated the floor of Nili Patera. The cone grew from even later flows, apparently after evolution of the underground magma had thickened its texture so that the erupted lava would mound up.

"We can read a series of chapters in this history book and know that the cone grew from the last gasp of a giant volcanic system," said John "Jack" Mustard, professor of geological sciences and a co-author of the paper, who is Skok's thesis adviser at Brown. "The cooling and solidification of most of the magma concentrated its silica and water content."

Observations by cameras on the Mars Reconnaissance Orbiter revealed patches of bright deposits near the summit of the cone, fanning down its flank, and on flatter ground in the vicinity. The Brown researchers partnered with Scott Murchie of Johns Hopkins University Applied Physics Laboratory to analyze the bright exposures with the Compact Reconnaissance Imaging Spectrometer for (CRISM) instrument on the orbiter.

Silica can be dissolved, transported and concentrated by hot water or steam. Hydrated silica identified by the spectrometer in uphill locations — confirmed by stereo imaging — indicates that hot springs or fumaroles fed by underground heating created these deposits. Silica deposits around hydrothermal vents in Iceland are among the best parallels on Earth.

"The habitable zone would have been within and alongside the conduits carrying the heated water," Murchie said.

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jsa09
3 / 5 (1) Oct 31, 2010
I would hardly call it a warm wet period when evidence indicates that perhaps water was spurting out of the ground.

Think of a geyser into martian atmosphere - all that water would quickly turn to ice and sublimate away. There might be a warm wet spot that does not make a warm wet climate.
Parsec
4 / 5 (4) Nov 01, 2010
The degradation of the Martian atmosphere took place due to erosion from the solar wind and probably took a few billion years. Its very likely that 3 billion years ago the planet had a much denser atmosphere. Probably a lot less dense that Earth's, but denser than todays.
kevinrtrs
2.1 / 5 (7) Nov 01, 2010
There's zero evidence that this all happened 3.5 billion years ago. How exactly do they know it wasn't 3.7 billion years ago? or for that matter 2.3 million years ago?

The estimate for age is shear speculation and is then stated here as fact - especially for those who are wont to believe in such ages.

They least they could have done was to say that "it is thought that..." or "we have reason believe that..."
As it stands they are using the guess-o-fact regime to take a guess at an age and then make it into a fact.
Anyone who then dares to question this is made out to be a nut-case or idiot who doesn't know science and needs to come out of flat earth thought to join the uber-intelligent in the modern evolutionists era.

Perhaps more stringent questioning by evolutionist adherents would produce better science. But then they've already been intimidated too much.
deatopmg
1 / 5 (1) Nov 01, 2010
@Parsec - It is likely that 3.5 byrs ago the atmospheric pressure on Mars was many times the present pressure on Earth based on the rate of atmospheric loss that is occurring now.
Skeptic_Heretic
not rated yet Nov 02, 2010
The estimate for age is shear speculation and is then stated here as fact - especially for those who are wont to believe in such ages.
You mean estimates, don't you? After all, there are over 40 methods used to establish the chronology of an item in most cases, and thoose need to agree in order for someone to state an age as fact. If they are stating the age as fact, that means that multiple unrelated methods were used. You know, other than just reading one book to get an answer, they checked the entire library.

I'd recommend you try the same, multi-book method to establish your own world view.
Anyone who then dares to question this is made out to be a nut-case or idiot who doesn't know science and needs to come out of flat earth thought to join the uber-intelligent in the modern evolutionists era.
No Kev, we just think you were abused as a child and prevented from being curious.