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

[Ron Baalke]

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 

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