NASA Mission Helps Craft 3-D Image Of Buried Mars Flood Channels

       NASA Mission Helps Craft 3-D Image Of Buried Mars Flood Channels

PR Newswire

WASHINGTON, March 7, 2013

WASHINGTON, March 7, 2013 /PRNewswire-USNewswire/ --NASA's Mars
Reconnaissance Orbiter (MRO) has provided images allowing scientists for the
first time to create a 3-D reconstruction of ancient water channels below the
Martian surface.

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

The spacecraft took numerous images during the past few years that showed
channels attributed to catastrophic flooding in the last 500 million years.
Mars during this period had been considered cold and dry. These channels are
essential to understanding the extent to which recent hydrologic activity
prevailed during such arid conditions. They also help scientists determine
whether the floods could have induced episodes of climate change.

The estimated size of the flooding appears to be comparable to the ancient
mega flood that created the Channeled Scablands in the Pacific Northwest
region of the United States in eastern Washington.

The findings are reported in the March 7 issue of Science Express by a team of
scientists from NASA, the Smithsonian Institute, and the Southwest Research
Institute in Houston.

"Our findings show the scale of erosion that created the channels previously
was underestimated and the channel depth was at least twice that of previous
approximations," said Gareth Morgan, a geologist at the National Air and Space
Museum's Center for Earth and Planetary Studies in Washington and lead author
on the paper. "This work demonstrates the importance of orbital sounding radar
in understanding how water has shaped the surface of Mars."

The channels lie in Elysium Planitia, an expanse of plains along the Martian
equator and the youngest volcanic region on the planet. Extensive volcanism
throughout the last several hundred million years covered most of the surface
of Elysium Planitia, and this buried evidence of Mars' older geologic history,
including the source and most of the length of the 620-mile-long
(1000-kilometer-long) Marte Vallis channel system. To probe the length, width
and depth of these underground channels, the researchers used MRO's Shallow
Radar (SHARAD).

Marte Vallis' morphology is similar to more ancient channel systems on Mars,
especially those of the Chryse basin. Many scientists think the Chryse
channels likely were formed by the catastrophic release of ground water,
although others suggest lava can produce many of the same features. In
comparison, little is known about Marte Vallis.

With the SHARAD radar, the team was able to map the buried channels in three
dimensions with enough detail to see evidence suggesting two different phases
of channel formation. One phase etched a series of smaller branching, or
"anastomosing," channels that are now on a raised "bench" next to the main
channel. These smaller channels flowed around four streamlined islands. A
second phase carved the deep, wide channels.

"In this region, the radar picked up multiple 'reflectors,' which are surfaces
or boundaries that reflect radio waves, so it was possible to see multiple
layers," said Lynn Carter, the paper's co-author from NASA's Goddard Space
Flight Center in Greenbelt, Md. "We have rarely seen that in SHARAD data
outside of the polar ice regions of Mars."

The mapping also provided sufficient information to establish the floods that
carved the channels originated from a now-buried portion of the Cerberus
Fossae fracture system. The water could have accumulated in an underground
reservoir and been released by tectonic or volcanic activity.

"While the radar was probing thick layers of dry, solid rock, it provided us
with unique information about the recent history of water in a key region of
Mars," said co-author Jeffrey Plaut of NASA's Jet Propulsion Laboratory (JPL),
Pasadena, Calif.

The Italian Space Agency provided the SHARAD instrument on MRO and Sapienza
University of Rome leads its operations. JPL manages MRO for NASA's Science
Mission Directorate in Washington. Lockheed Martin Space Systems of Denver
built the orbiter and supports its operations.

The 3-D image can be viewed online at:

http://photojournal.jpl.nasa.gov/catalog/PIA16767

For more about NASA's MRO 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; Jia-Rui Cook, +1-818-354-0850, jccook@jpl.nasa.gov,
or Guy Webster, +1-818-354-6278, guy.webster@jpl.nasa.gov, Jet Propulsion
Laboratory, Pasadena, Calif.; Elizabeth Zubritsky, Goddard Space Flight
Center, Greenbelt, Md., +1-301-614-5438, elizabeth.a.zubritsky@nasa.gov;
Isabel Lara, Smithsonian Air and Space Museum, Washington, +1-202-633-2374,
larai@si.edu
 
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