Martian Crater Once May Have Held Groundwater-Fed Lake

            Martian Crater Once May Have Held Groundwater-Fed Lake

PR Newswire

PASADENA, Calif., Jan. 20, 2013

PASADENA, Calif., Jan. 20, 2013 /PRNewswire-USNewswire/ -- A NASA spacecraft
is providing new evidence of a wet underground environment on Mars that adds
to an increasingly complex picture of the Red Planet's early evolution.

(Logo: http://photos.prnewswire.com/prnh/20081007/38461LOGO )

The new information comes from researchers analyzing spectrometer data from
NASA's Mars Reconnaissance Orbiter (MRO), which looked down on the floor of
McLaughlin Crater. The Martian crater is 57 miles (92 kilometers) in diameter
and 1.4 miles (2.2 kilometers) deep. McLaughlin's depth apparently once
allowed underground water, which otherwise would have stayed hidden, to flow
into the crater's interior.

Layered, flat rocks at the bottom of the crater contain carbonate and clay
minerals that form in the presence of water. McLaughlin lacks large inflow
channels, and small channels originating within the crater wall end near a
level that could have marked the surface of a lake.

Together, these new observations suggest the formation of the carbonates and
clay in a groundwater-fed lake within the closed basin of the crater. Some
researchers propose the crater interior catching the water and the underground
zone contributing the water could have been wet environments and potential
habitats. The findings are published in Sunday's online edition of Nature
Geoscience.

"Taken together, the observations in McLaughlin Crater provide the best
evidence for carbonate forming within a lake environment instead of being
washed into a crater from outside," said Joseph Michalski, lead author of the
paper, which has five co-authors. Michalski also is affiliated with the
Planetary Science Institute in Tucson, Ariz., and London's Natural History
Museum.

Michalski and his co-authors used the Compact Reconnaissance Imaging
Spectrometer for Mars (CRISM) on MRO to check for minerals such as carbonates,
which are best preserved under non-acidic conditions.

"The MRO team has made a concerted effort to get highly processed data
products out to members of the science community like Dr. Michalski for
analysis," said CRISM Principal Investigator Scott Murchie of the Johns
Hopkins University Applied Physics Laboratory in Laurel, Md. "New results like
this show why that effort is so important."

Launched in 2005, MRO and its six instruments have provided more
high-resolution data about the Red Planet than all other Mars orbiters
combined. Data is made available for scientists worldwide to research, analyze
and report their findings.

"A number of studies using CRISM data have shown rocks exhumed from the
subsurface by meteor impact were altered early in Martian history, most likely
by hydrothermal fluids," Michalski said. "These fluids trapped in the
subsurface could have periodically breached the surface in deep basins such as
McLaughlin Crater, possibly carrying clues to subsurface habitability."

McLaughlin Crater sits at the low end of a regional slope several hundreds of
miles long on the western side of the Arabia Terra region of Mars. As on
Earth, groundwater-fed lakes are expected to occur at low regional elevations.
Therefore, this site would be a good candidate for such a process.

"This new report and others are continuing to reveal a more complex Mars than
previously appreciated, with at least some areas more likely to reveal signs
of ancient life than others," said MRO project scientist Rich Zurek of NASA's
Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

The Johns Hopkins University Applied Physics Laboratory in Laurel, Md.,
provided and operates CRISM. JPL manages MRO for NASA's Science Mission
Directorate in Washington. Lockheed Martin Space Systems in Denver built the
orbiter.

To see an image of the carbonate-bearing layers in McLaughlin Crater, visit:

http://photojournal.jpl.nasa.gov/catalog/PIA16710

For more about the Mars Reconnaissance Orbiter mission, visit:

http://www.nasa.gov/mro

SOURCE NASA

Website: http://www.nasa.gov
Contact: Dwayne Brown, Headquarters, Washington, +1-202-358-1726,
dwayne.c.brown@nasa.gov; Guy Webster, Jet Propulsion Laboratory, Pasadena,
Calif., +1-818-354-6278, guy.webster@jpl.nasa.gov; Alan Fischer, Planetary
Science Institute, Tucson, Ariz., +1-520-382-0411, fischer@psi.edu