[meteorite-list] MRO Helps Craft 3-D Image Of Buried Mars Flood Channels

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 7 Mar 2013 16:10:17 -0800 (PST)
Message-ID: <201303080010.r280AHJP027381_at_zagami.jpl.nasa.gov>

March 7, 2013

Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown at nasa.gov

Jia-Rui Cook/Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0850/6278
jccook at jpl.nasa.gov / guy.webster at jpl.nasa.gov

Elizabeth Zubritsky
Goddard Space Flight Center, Greenbelt, Md.
301-614-5438
elizabeth.a.zubritsky at nasa.gov

Isabel Lara
Smithsonian Air and Space Museum, Washington
202-633-2374
larai at si.edu

RELEASE: 13-070

NASA MISSION HELPS CRAFT 3-D IMAGE OF BURIED MARS FLOOD CHANNELS

WASHINGTON -- 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.

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 Institution, 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

-end-
Received on Thu 07 Mar 2013 07:10:17 PM PST