Bright blue marks a deposit of chloride (salt) minerals in the southern highlands of Mars in this false-color image, which highlights mineral composition differences. Photo Credit: NASAMarch 27, 2008 (Sawf News) - Her research led Central Michigan University geologist Kathleen Benison to predict that salt would eventually be detected on the surface of Mars.
The journal Science reported this week that a research team led by Mikki Osterloo of the University of Hawaii, Honolulu made that discovery, with the help of NASA's Mars Odyssey orbiter.
The team discovered evidence of salt deposits, which scientists believe were formed approximately 3.5 to 3.9 billion years ago. These deposits point to places where water once was abundant and where evidence might exist of possible Martian life from the Red Planet's past.
Researchers found approximately 200 places on southern Mars that show spectral characteristics consistent with chloride minerals. Chloride is part of many types of salt, such as sodium chloride or table salt. The sites range from about a square kilometer (0.4 square mile) to 25 times that size.
"They could come from groundwater reaching the surface in low spots," Osterloo said. "The water would evaporate and leave mineral deposits, which build up over years. The sites are disconnected, so they are unlikely to be the remnants of a global ocean."
A few of Benison's initial thoughts on the subject:
- "The finding of salt on Mars absolutely encourages further search for life there. The confirmation of salt on Mars strengthens the case for acid saline environments on Mars in the past."
- "Various acid saline lake systems that I study in Western Australia are strikingly similar to certain areas on Mars. This is what led me to predict that compounds in the same grouping as those present on Earth would eventually be documented on Mars."
- "If life ever existed on Mars, it is likely that microfossils will have been insulated by halite (salt) and hematite (iron oxide), which together protect microfossils from dissolution by water and breakdown by ultra violet radiation."
Kathleen Benison is an authority on deciphering past environments, water chemistry, climate and life from clues contained in sedimentary rocks. Benison's main research project is a comprehensive study of acid saline lake and groundwater systems in southwestern Australia. This work has implications for red bed formation, life in extreme environments, role of long-term weathering on brine evolution, and gaining a better understanding of Mars.
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