[meteorite-list] Habitable Martian Environments Could be Deep Beneath Planet's Surface

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 11 Oct 2010 10:40:59 -0700 (PDT)
Message-ID: <201010111740.o9BHexTK000400_at_zagami.jpl.nasa.gov>

NEWS RELEASE FROM THE PLANETARY SCIENCE INSTITUTE

SENT:
Oct. 11, 2010

FROM:
Alan Fischer
Public Information Office
Planetary Science Institute
520-885-5648
520-622-6300
fischer at psi.edu


Habitable Martian Environments Could be Deep Beneath Planet's Surface

A new discovery of hydrothermally altered carbonate-bearing
rocks on Mars points toward habitable environments deep in
the Martian crust, a Planetary Science Institute researcher
said.

A deposit of carbonate rocks that once existed 6 km below the
surface of Mars was uplifted and exposed by an ancient meteor
impact, said Joseph Michalski, research scientist with PSI. The
carbonate minerals exist along with hydrated silicate minerals
of a likely hydrothermal origin.

Using data returned from NASA's Mars Reconnaissance Orbiter (MRO)
spacecraft, researchers have spotted this unique mineralogy
within the central peak of a crater to the southwest of a giant
Martian volcano named Syrtis Major. With infrared spectra from
the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM),
planetary geologists detected the hydrothermal minerals from
their spectroscopic fingerprints.

Visible images from the High Resolution Imaging Science Experiment
(HiRISE) camera aboard MRO show that the carbonates and hydrated
silicate minerals occur within deformed bedrock that was exhumed by
an ancient meteor impact that poked through the volcanic upper
crust of Mars.

"Carbonate rocks have long been a Holy Grail of Mars exploration
for several reasons," Michalski said. "One reason is because
carbonates form with the ocean and within lakes on Earth, so the
same could be true for ancient Mars - such deposits could indicate
past seas that were once present on Mars. Another reason is because
we suspect that the ancient Martian atmosphere was probably denser
and CO2-rich, but today the atmosphere is quite thin so we infer
that the CO2 must have gone into carbonate rocks somewhere on Mars."

Michalski and co-author Paul B. Niles of NASA Johnson Space Center
recently published the results in a paper titled "Deep crustal
carbonate rocks exposed by meteor impact on Mars" in Nature Geoscience.

While this is not the first detection of carbonates on Mars, Michalski
said, "This detection is significant because it shows other carbonates
detected by previous workers, which were found in a fairly limited
spatial extent, were not a localized phenomenon. Carbonates may have
formed over a very large region of ancient Mars, but been covered up
by volcanic flows later in the history of the planet. A very exciting
history of water on Mars may be simply covered up by younger lava!"

The discovery also has implications for the habitability of the
Martian crust.

"The presence of carbonates along with hydrothermal silicate minerals
indicates that a hydrothermal system existed in the presence of CO2
deep in the Martian crust," Michalski says. "Such an environment is
chemically similar to the type of hydrothermal systems that exist
within the ocean floor of Earth, which are capable of sustaining
vast communities of organisms that have never seen the light of day.

"The cold, dry surface of Mars is a tough place to survive, even
for microbes. If we can identify places where habitable environments
once existed at depth, protected from the harsh surface environment,
it is a big step forward for astrobiological exploration of the red
planet."

NASA's Mars Data Analysis Program provided funding for the research
project.


CONTACT:
Joseph Michalski
Research Scientist
+33 6 07 32 91 82
michalski at psi.edu

PSI INFORMATION:
Mark V. Sykes
Director
520-622-6300
sykes at psi.edu

PSI HOMEPAGE:
http://www.psi.edu
Received on Mon 11 Oct 2010 01:40:59 PM PDT