[meteorite-list] Upgrade Helps NASA Study Mineral Veins on Mars (MSL)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 11 Nov 2015 12:16:01 -0800 (PST)
Message-ID: <201511112016.tABKG1Kn016976_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?feature=4766

Upgrade Helps NASA Study Mineral Veins on Mars
Jet Propulsion Laboratory
November 11, 2015

Scientists now have a better understanding about a site with the most
chemically diverse mineral veins NASA's Curiosity rover has examined on
Mars, thanks in part to a valuable new resource scientists used in analyzing
data from the rover.

Curiosity examined bright and dark mineral veins in March 2015 at a site
called "Garden City," where some veins protrude as high as two finger
widths above the eroding bedrock in which they formed.

The diverse composition of the crisscrossing veins points to multiple
episodes of water moving through fractures in the bedrock when it was
buried. During some wet periods, water carried different dissolved substances
than during other wet periods. When conditions dried, fluids left clues
behind that scientists are now analyzing for insights into how ancient
environmental conditions changed over time.

"These fluids could be from different sources at different times," said
Diana Blaney, a Curiosity science team member at NASA's Jet Propulsion
Laboratory, Pasadena, California. "We see crosscutting veins with such
diverse chemistry at this localized site. This could be the result of
distinct fluids migrating through from a distance, carrying chemical signatures
from where they'd been."

Researchers used Curiosity's laser-firing Chemistry and Camera (ChemCam)
instrument to record the spectra of sparks generated by zapping 17 Garden
City targets with the laser. The unusually diverse chemistry detected
at Garden City includes calcium sulfate in some veins and magnesium sulfate
in others. Additional veins were found to be rich in fluorine or varying
levels of iron.

As researchers analyzed Curiosity's observations of the veins, the ChemCam
team was completing the most extensive upgrade to its data-analysis toolkit
since Curiosity reached Mars in August 2012. They more than tripled --
to about 350 -- the number of Earth-rock geochemical samples examined
with a test version of ChemCam. This enabled an improvement in their data
interpretation, making it more sensitive to a wider range of possible
composition of Martian rocks.

Blaney said, "The chemistry at Garden City would have been very enigmatic
if we didn't have this recalibration."

The Garden City site is just uphill from a mudstone outcrop called "Pahrump
Hills," which Curiosity investigated for about six months after reaching
the base of multi-layered Mount Sharp in September 2014. The mission is
examining ancient environments that offered favorable conditions for microbial
life, if Mars has ever hosted any, and the changes from those environments
to drier conditions that have prevailed on Mars for more than 3 billion
years. Curiosity has found evidence that base layers of Mount Sharp were
deposited in lakes and rivers. The wet conditions recorded by the Garden
City veins existed in later eras, after the mud deposited in lakes had
hardened into rock and cracked.

Eye-catching geometry revealed in images of the veins offers additional
clues. Younger veins continue uninterrupted across intersections with
veins that formed earlier, indicating relative ages.

ChemCam provides the capability of making distinct composition readings
of multiple laser targets close together on different veins, rather than
lumping the information together. The chemistry of these veins is also
related to mineral alteration observed at other places on and near Mount
Sharp. What researchers learned here can be used to help understand a
very complex fluid chemical history in the region. Since leaving Garden
City, Curiosity has climbed to higher, younger layers of Mount Sharp.

Today, Blaney presented findings from ChemCam's Garden City investigations
at the annual meeting of the American Astronomical Society's Division
for Planetary Science, in National Harbor, Maryland.

The U.S. Department of Energy's Los Alamos National Laboratory in Los
Alamos, New Mexico, developed ChemCam in partnership with scientists and
engineers funded by the French national space agency. More information
is available at:

http://www.msl-chemcam.com

NASA's Jet Propulsion Laboratory built Curiosity and manages the project
for NASA's Science Mission Directorate in Washington. For more the mission,
visit:

http://www.nasa.gov/msl

http://mars.jpl.nasa.gov/msl

You can follow the mission on Facebook and Twitter at:

http://www.facebook.com/marscuriosity

http://www.twitter.com/marscuriosity


Media Contact

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster at jpl.nasa.gov

Dwayne Brown / Laurie Cantillo
Headquarters, Washington
202-358-1726 / 202-358-1077
dwayne.c.brown at nasa.gov/ laura.l.cantillo at nasa.gov
Received on Wed 11 Nov 2015 03:16:01 PM PST