"NASA’s Mars Reconnaissance Orbiter 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. During this period, Mars had been otherwise 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 in Washington, and the Southwest Research Institute in Builder, Colo.
"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 the Mars Reconnaissance Orbiter’s Shallow Radar (SHARAD). ”