From: Planetary Science Institute
Posted: Sunday, November 28, 2010
An international research team led by the Planetary Science Institute has found evidence for reservoirs of liquid water on Mars at shallow crustal depths of as little as tens of meters.
J. Alexis Palmero Rodriguez, research scientist at PSI, and the research team came to this conclusion after studying collapsed terrains that occur within some of the solar system's largest channels.
Investigations of similar but vastly larger zones of collapse located where these channels initiate have led previous investigations to postulate that the upper crust of Mars contained vast aquifer systems concealed underneath a global frozen layer kilometers in thickness. However, these zones of large-scale collapse are rare on Mars and their formation most likely took place under exceptional hydrogeologic conditions. The PSI-led team's work documents the distribution of groundwater within crustal zones located beyond these regions.
Citing geologic evidence found in the planet's largest system of channels located in southern circum-Chryse and results from thermal numerical modeling, Rodriguez and his co-authors propose in an article published in Icarus that groundwater reservoirs may have been common within the Martian upper crust.
The numerical model implies that where fine-grained, unconsolidated sedimentary deposits existed on top of an icy permafrost layer, melting of ground ice and the development of subsurface aquifers could have taken place at shallow depths.
Extrapolations of their results to the present Martian conditions imply that groundwater may currently exist underneath thermally insulating fine-grained sedimentary deposits approximately 120 meters in thickness. Thus, despite large differences in hydrogeologic histories, average surface temperatures, and internal heat flows of Earth and Mars, some areas of Mars might be similar to typical permafrost on Earth, where shallow aquifers are confined by thin layers of icy permafrost.
These reservoirs could mean the presence of accessible water near the Martian surface, Rodriguez said, which could greatly reduce the costs of future manned exploration of the planet. In addition, it could mean habitable environments may exist at shallow depths, he said.
This research was funded by a grant to PSI from the NASA Mars Data Analysis Program.
Rodriguez is lead author on the paper. Co-authors are: Jeffrey S. Kargel, Department of Hydrology & Water Resources, University of Arizona; Kenneth L. Tanaka, Astrogeology Science Center, U.S. Geological Survey; David A. Crown, Planetary Science Institute; Daniel C. Berman, Planetary Science Institute; Alberto G. Fairen, SETI Institute and Space Science and Astrobiology Division, NASA Ames Research Center; Victor R. Baker, Department of Hydrology & Water Resources, University of Arizona; Roberto Furfaro, Department of Aerospace & Mechanical Engineering, University of Arizona; Pat Candelaria, Department of Aerospace and Mechanical Engineering, University of Arizona and Sho Sasaki, National Astronomical Observatory of Japan.
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The Planetary Science Institute is a private, nonprofit 501(c)(3) corporation dedicated to solar system exploration. It is headquartered in Tucson, Arizona, where it was founded in 1972. PSI scientists are involved in numerous NASA and international missions, the study of Mars and other planets, the Moon, asteroids, comets, interplanetary dust, impact physics, the origin of the solar system, extrasolar planet formation, dynamics, the rise of life, and other areas of research. They conduct fieldwork in North America, Australia and Africa. They also are actively involved in science education and public outreach through school programs, children's books, popular science books and art.
PSI scientists are based in 17 states, the United Kingdom, France, Switzerland, Russia and Australia.
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