[meteorite-list] NASA Mars Orbiter Sees Effects of Ancient Underground Fluid (MRO)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 15 Feb 2007 12:33:03 -0800 (PST)
Message-ID: <200702152033.MAA06009_at_zagami.jpl.nasa.gov>

NASA MARS ORBITER SEES EFFECTS OF ANCIENT UNDERGROUND FLUIDS
(From Lori Stiles, University Communications, 520-626-4402)

Thursday, February 15, 2007

----------------------------------------------------------------
SUMMARY: Liquid or gas flowed through cracks penetrating underground rock
on ancient Mars, University of Arizona scientists on the High Resolution
Imaging Experiment team report today in Science. These fluids may have
produced conditions to support possible habitats for microbial life. Contact
information is listed at the end of the following NASA news release.
----------------------------------------------------------------

Liquid or gas flowed through cracks penetrating underground rock on ancient
Mars, according to a report based on some of the first observations by
NASA's Mars Reconnaissance Orbiter. These fluids may have produced
conditions to support possible habitats for microbial life.

These ancient patterns were revealed when the most powerful telescopic
camera ever sent to Mars began examining the planet last year. The camera
showed features as small as approximately 3 feet across. Mineralization took
place deep underground, along faults and fractures. These mineral deposits
became visible after overlying layers eroded away throughout millions of
years.

Chris Okubo, a geologist at The University of Arizona, Tucson, discovered
the patterns in an image of exposed layers in a Martian canyon named Candor
Chasma. The image was taken in September 2006 from the High Resolution
Imaging Science Experiment camera aboard the orbiter.

"What caught my eye was the bleaching or lack of dark material along the
fracture. That is a sign of mineral alteration by fluids that moved through
those joints," said Okubo. ?It reminded me of something I had seen during
field studies in Utah, that is light-tone zones, or 'haloes,' on either side
of cracks through darker sandstone.?

"This result shows how orbital observations can identify features of
particular interest for future exploration on the surface or in the
subsurface or from sample return," said Alfred McEwen, principal
investigator for the camera at The University of Arizona, Tucson. "The
alteration along fractures, concentrated by the underground fluids, marks
locations where we can expect to find key information about chemical and
perhaps biologic processes in a subsurface environment that may have been
habitable," McEwen said.

The haloes visible along fractures seen in the Candor Chasma image appear
to be slightly raised relative to surrounding, darker rock. This is evidence
that the circulating fluids hardened the lining of the fractures, as well as
bleaching it. The harder material would not erode away as quickly as softer
material farther from the fractures.

The most likely origin for these features is that minerals that were
dissolved in water came out of solution and became part of the rock material
lining the fractures. Another possibility is that the circulating fluid was
a gas, which may or may not have included water vapor in its composition,
Okubo said.

Similar haloes adjacent to fractures show up in images that the
high-resolution camera took of other places on Mars after the initial Candor
Chasma image. "We are excited to be seeing geological features too small to
have been noticed previously," Okubo said.

"This publication is just the first of many, many to come. The analysis is
based on test observations taken even before the start of our main science
phase. Since then, Mars Reconnaissance Orbiter has returned several terabits
of science data, sustaining a pace greater than any other deep space
mission. This flood of data will require years of study to exploit their
full value, forever increasing our understanding of Mars and its history of
climate change," said Richard Zurek, project scientist for the Mars
Reconnaissance Orbiter at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Okubo and McEwen report these findings in the Feb. 16 edition of the
journal Science. Images showing the haloes along fractures are available on
the Web at: http://www.nasa.gov/mission_pages/MRO/news/20070215.html and
at http://hirise.lpl.arizona.edu/publications/Okubo_McEwen_2007 The Jet
Propulsion Laboratory manages the orbiter mission for NASA?s Science Mission
Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime
contractor for the project and built the spacecraft. The University of
Arizona operates the High Resolution Imaging Science Experiment camera. Ball
Aerospace and Technologies Corp., Boulder, Colo. built the camera.

----------------------------------------------------------
Science Contact Information
 Chris H. Okubo 520-626-1458 chriso at lpl.arizona.edu
 Alfred S. McEwen 520-621-4573 mcewen at lpl.arizona.edu

Media Contact Information
 Tabatha Thompson, NASA Headquarters, Washington 202-358-3895
 Guy Webster, Jet Propulsion Laboratory, Pasadena 818-354-6278
 Lori Stiles, University of Arizona, Tucson 520-626-4402

Images for download:
http://www.nasa.gov/mission_pages/MRO/news/20070215.html
-----------------------------------------------------------
Received on Thu 15 Feb 2007 03:33:03 PM PST