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

[Ron Baalke]

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