Planets

Mars Rover Finds Rich Mineral Stew in Fractured Rock

Chemical analysis by NASA’s Mars rover Curiosity indicates that water made several repeat appearances to create the rich mineral veins at a site called “Garden City” in the lower part of Mount Sharp.

Chemical analysis by NASA's Mars rover Curiosity indicates that water made several repeat appearances to create the rich mineral veins at a site called "Garden City" in the lower part of Mount Sharp.

The veins form in places where fluids have move through fractured rocks, depositing minerals and leaving telltale chemical fingerprints on surrounding areas. Some of the mineral veins at Garden City protrude the equivalent of two finger widths above the now-eroded bedrock in which they formed.

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The site was not accessible to Curiosity's drill, but in March the rover zapped 17 targets with its ChemCam laser and discovered a diverse chemical stew.

"I think this has some of the most extreme chemistry that we've seen in a very localized area. There's been other places where we've seen very strong chemistry, but in this kind of meter-square area, up until this point I don't think we've seen anywhere with this much variability and this much unexpected chemistry," Curiosity scientist Diana Blaney, with NASA's Jet Propulsion Laboratory in Pasadena, Calif, told Discovery News.

Many of the veins contain rich deposits of calcium sulfate. Others are laced with magnesium sulfate or fluorine. Levels of iron vary.

The three-mile-high Mount Sharp rises from the floor of a huge impact basin that once held water. The Garden City veins were created after mud in the lake had hardened into rock and cracked.

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"At Garden City, because there's such good preservation and we get the cross-cutting, we're able to start pulling out some chemical signatures that we saw at different places into distinct fluids. And by looking at the cross-cutting relationships and the difference in chemistries, I think we have really strong evidence that they're distinct fluid events," Blaney said.

"We don't know how far apart in time these different events occurred, or what was driving them," she added. "I think as we get more information on what it's going to take to chemically evolve these fluids, we might be able to pin that down."

Curiosity is scouring Mount Sharp to look for habitats that could have supported past life and for places suitable to preserve organics.

"Veins have a good potential - because it's a fluid and there is crystallization - to include things as inclusions, but the organic preservation has a lot of factors," Blaney said.

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"These veins are not able to be drilled by the rover, but there are more veins at an even larger scale that are ahead of us. I know people are looking to see if there might be places where we can sample them," she said.

The rover is currently exploring younger, higher regions of the mountain.

The research was presented this week at an American Astronomical Society planetary science meeting in National Harbor, Maryland.

NASA’s Mars Curiosity rover probed a network of prominent mineral veins below a cap rock ridge on the lower part of Mount Sharp.

Nearly one (Earth) year ago, NASA's Curiosity rover arrived at Mount Sharp, the key science destination of its mission. The rover has now spent three Earth years on the Red Planet, looking at rocks and environment to try to piece together the ancient past of Mars. Was it habitable for life? If so, did the life disappear? Why did the conditions change? These are all questions investigators are trying to learn the answers to. In this brief rundown of the science being done on Mount Sharp (officially known as Aeolis Mons), we've picked out some of the most intriguing and, frankly, beautiful photos of Curiosity's mountain.

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After extensive practice taking pictures of the rover, Curiosity's "selfies" are getting pretty amazing.

This is one of the latest ones

from Curiosity, showing it perched at the Marias Pass just after doing some drilling. While the selfies are used as a public relations tool, NASA also uses these pictures to monitor the condition of the rover in the harsh Martian environment. One thing the agency

is keeping an eye on is wheel damage

, for example.

Yep, that's a rock -- there are a lot of those on Mars. But look more closely at each one, and they reveal surprises. This particular rock is

embedded with silica

, a silicon-oxygen rock-forming compound that often shows up on Earth as quartz. It's an unusual find for Mars, and the team said it is going to take a closer look to see if it could preserve organic materials. Organics are considered building blocks of life, but not necessarily signs of life itself.

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Curiosity has a laser on board (called the Chemistry and Camera or ChemCam instrument) that shoots at rocks to figure out what they are made of. But for months, the auto-focuser malfunctioned and required multiple laser shots to be sent, slowing down the science. This image shows the result

after a successful software update

that takes several images and figures out how to target the focuser from there.

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In 28 pictures stitched together, Curiosity uncovered

an extensive network of mineral veins

at a site investigators dubbed "Garden City." These veins are created when a liquid cuts through cracks in a rock and leaves minerals behind. At the time this picture was taken, NASA was trying to figure out what the fluids were made of, and how the rock changed after the fluids touched it. It's all part of better understanding the ancient wet past on Mars and prospects for life.

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Sometimes you can't predict what will happen when you do science. In this case, Curiosity's drill did a test to see if this "Mojave" rock could be suitable to collect a sample...

and the rock shattered

. While it wasn't a total surprise that the rock broke, what made this test interesting was it

created a few rock chips

. This gave Curiosity an opportunity to look at what a new rock looks like before it gets all weathered by Martian wind and elements.

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In December, couple of building blocks of life came to light: Curiosity saw a

10-fold spike and fall in methane

around this time, and

detected carbon-bearing organic molecules on Mars

. While neither of these are necessarily signs of life, they point to conditions that could have been friendly for life at some point. Also, Curiosity got to flex its drill at the "Cumberland" rock target, which was a good thing as

a NASA senior review said the drill wasn't being used enough

(making it hard to justify the cost and complication).

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The very first hole

that Curiosity created in Mount Sharp revealed something exciting: the mineral it found was the same as one seen from orbit in the same region. Specifically, the rover

found evidence of hematite

, an iron oxide mineral that can precipitate out of water. Hematite was noted as a mineral of interest when the Curiosity landing site was being selected in 2010.

Image: Curiosity's path during the first few weeks at Mount Sharp in fall (Earth's northern hemisphere fall) 2014.

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