NASA Ames Research Center | 2011 July 01
Martian “Rust” Could Possibly Point To Past WaterNASA scientists are seeing new evidence that suggests traces of water on Mars are under a thin varnish of iron oxide, or rust, similar to conditions found on desert rocks in California's Mojave Desert.
Mars could be spotted with many more patches of carbonates than originally suspected. Carbonates are minerals that form readily in large bodies of water and can point to a planet's wet history. Although only a few small outcrops of carbonates have been detected on Mars, scientists believe many more examples are blocked from view by the rust. The findings appear in the Friday July 1, online edition of the International Journal of Astrobiology.
"The plausibility of life on Mars depends on whether liquid water dotted its landscape for thousands or millions of years," said Janice Bishop, a planetary scientist at NASA's Ames Research Center at the SETI Institute at Moffett Field, Calif., and the paper's lead author. "It's possible that an important clue, the presence of carbonates, has largely escaped the notice of investigators trying to learn if liquid water once pooled on the Red Planet."
Scientists conduct field experiments in desert regions because the extremely dry conditions are similar to Mars. Researchers realized the importance of the varnish earlier this year when Bishop and Chris McKay, a planetary scientist at Ames investigated carbonate rocks coated with iron oxides collected in a location called Little Red Hill in the Mojave Desert. "When we examined the carbonate rocks in the lab, it became evident that an iron oxide skin may be hindering the search for clues to the Red Planet's hydrological history," McKay said. "We found that the varnish both altered and partially masked the spectral signature of the carbonates."
McKay also found dehydration-resistant blue-green algae under the rock varnish. Scientists believe the varnish may have extended temporarily the time that Mars was habitable, as the planet's surface slowly dried up.
"The organisms in the Mojave Desert are protected from deadly ultraviolet light by the iron oxide coating," McKay said. "This survival mechanism might have played a role if Mars once had life on the surface."
In addition to being used to help characterize Mars' water history, carbonate rocks also could be a good place to look for the signatures of early life on the Red Planet. Every mineral is made up of atoms that vibrate at specific frequencies to produce a unique fingerprint that allows scientists to accurately identify its composition.
Research data were similar to observations provided by NASA's Mars Reconnaissance Orbiter (MRO) spacecraft, as it orbited an ancient region of Mars called Nili Fossae. The area revealed the strongest carbonate signature ever found. Although MRO recently detected small patches of carbonates, approximately 200-500 feet wide, on the Martian surface, the Mojave study suggests more patches may have been overlooked because their spectral signature could have been changed by the pervasive varnish.
"To better determine the extent of carbonate deposits on Mars, and by inference the ancient abundance of liquid water, we need to investigate the spectral properties of carbonates mixed with other minerals," Bishop said.
The varnish is so widespread that NASA's Mars Exploration Rovers, Spirit and Opportunity, used a motorized grinding tool to remove the rust-like overcoat on rocks before other instruments could inspect them. In 2010, scientists using data collected by Spirit also identified a small carbonate outcrop at a crater called Gusev. NASA's newest and most capable rover, the Mars Science Laboratory Curiosity is schedule to launch in November. It will use tools to study whether the Mars had environmental conditions favorable for supporting microbial life and favorable for preserving clues about whether life existed.
Universe Today | Tammy Plotner | 2011 July 01
Evidence Builds For Water on MarsIt’s called a carbonate and it’s a mineral that’s common to water-logged formations… be it here on Earth, or on Mars. Until now only a few carbonate deposits have been found on Mars, but scientists are beginning to suspect it has been hiding all along under a thin layer of iron oxide. Because rust never sleeps…
“The plausibility of life on Mars depends on whether liquid water dotted its landscape for thousands or millions of years,” said Janice Bishop, a planetary scientist at NASA’s Ames Research Center at the SETI Institute at Moffett Field, California. “It’s possible that an important clue, the presence of carbonates, has largely escaped the notice of investigators trying to learn if liquid water once pooled on the Red Planet.”
How did they come to this conclusion? By studying similar conditions on rocks found in the Mojave Desert. Because the arid conditions are similar to the Martian environment, investigators can assume carbonates are hiding behind a veneer of rust – keeping them from view. This new evidence came to light earlier this year when Bishop and Chris McKay – a planetary scientist at Ames – collected samples from an area called Little Red Hill.
“When we examined the carbonate rocks in the lab, it became evident that an iron oxide skin may be hindering the search for clues to the Red Planet’s hydrological history,” McKay said. “We found that the varnish both altered and partially masked the spectral signature of the carbonates.”
But rust wasn’t all they found… there was also a signature of dehydration-resistant blue-green algae. This biologic implication means the iron oxide coating may have also extended the time period that Mars could have supported such a life form. “The organisms in the Mojave Desert are protected from deadly ultraviolet light by the iron oxide coating,” McKay said. “This survival mechanism might have played a role if Mars once had life on the surface.”
Why are these carbonate findings important? Every mineral has a unique absorption bands, spectral frequencies and vibrational modes. Using this information, planetary scientists can identify composition. Because of the layer of rust, many carbonate deposits may have been overlooked because their spectral signatures were masked.
“To better determine the extent of carbonate deposits on Mars, and by inference the ancient abundance of liquid water, we need to investigate the spectral properties of carbonates mixed with other minerals,” Bishop said.
Like all rust, the deposits were so overwhelming that NASA’s Mars Exploration Rovers, Spirit and Opportunity, used a motorized grinding tool to “clean” samples before spectral examination. With NASA’s newest and most capable rover, the Mars Science Laboratory “Curiosity” mission nearing its launch date, we may be able to take another, closer look at possible life on Mars.
Because there’s more to the picture than meets the eye…
Space.com | 2011 July 25
NASA has chosen a landing site for its next Mars rover with the goal of seeking more signs of historical water on the planet, and a recent study suggests it may find it.
New evidence of Mars' watery past has surfaced, NASA scientists say, suggesting that telltale signs of the wet stuff may lurk under thin layers of rust seen scattered around the Red Planet, in areas that mirror conditions found in Earth's desert regions.
That's good news for NASA' Mars Science Laboratory Curiosity rover, which will be launched toward the planet later this year. The rover will land in Gale Crater, the space agency announced Friday (July 22), in part because the site offers promising conditions for the search for signs of water.
Scientists have long known that Mars is home to a few patches of carbonates — minerals that form readily in large bodies of water and can point to a planet’s wet history — yet they suspect that many more carbonates may be hidden beneath the rust (iron oxide) that coats many regions of the planet.
"It's possible that an important clue, the presence of carbonates, has largely escaped the notice of investigators trying to learn if liquid water once pooled on the Red Planet," said Janice Bishop, a planetary scientist at NASA's Ames Research Center at the SETI Institute at Moffett Field, Calif., in a statement.
"The plausibility of life on Mars depends on whether liquid water dotted its landscape for thousands or millions of years," said Bishop, the lead author on a paper published in the July 1 online edition of the International Journal of Astrobiology.
Scientists conduct field experiments in desert regions because the extremely dry conditions are similar to Mars. Researchers realized the importance of the varnish earlier this year when Bishop and Chris McKay, a planetary scientist at Ames, investigated carbonate rocks coated with iron oxides collected in the Mojave Desert.
When the scientists examined the rusty varnish in the lab, they found it had tinkered with the spectral signature of carbonates hidden underneath.
In addition, McKay found dehydration-resistant blue-green algae under the rock
varnish. Scientists believe the varnish may have extended temporarily the time that Mars was habitable, as the planet's surface slowly dried up.
"The organisms in the Mojave Desert are protected from deadly ultraviolet light by the iron oxide coating," McKay said. "This survival mechanism might have played a role if Mars once had life on the surface."
NASA’s Mars Reconnaissance Orbiter (MRO) spacecraft found patches of carbonates, approximately 200 to 500 feet (60 to 150 meters) wide, on the Martian surface, yet the Mojave study suggests more patches may have been overlooked because their spectral signature could have been changed by the planet's pervasive rusty coating.
In fact, the rusty varnish is so widespread that NASA's Mars Exploration Rovers, Spirit and Opportunity, were equipped with motorized grinding tools to remove the rusty overcoat on rocks before other instruments could inspect them.
