Do Martian clay deposits prove existence of liquid water? No.
A study found that the types of clays found on Mars to not necessarily require Earthlike aquatic conditions.
Rock fins up to about 1 foot tall are visible in this image by NASA's Mars Exploration Rover Opportunity taken on August 23. Orbital investigation of the area has identified a possibility of clay minerals in this area of the Cape York segment of the western rim of Endeavour Crater.
JPL-Caltech/Cornell Univ./Arizona State Univ./NASA/Reuters
In the hunt for evidence of a warmer, wetter past on Mars, clay deposits have been viewed as good indications that stable liquid water existed on its surface for some time 鈥� perhaps even long enough to allow life to develop. But new research conducted here on Earth shows that some clays don鈥檛 necessarily need lakes of liquid water to form. Instead they can be the result of volcanic activity, which is not nearly so hospitable to life.
A research team led by Alain Meunier of the Universit茅 de Poitiers in France studied lavas containing iron and magnesium 鈥� similar to ancient clays identified on the surface of Mars 鈥� in the French Polynesian atoll of Moruroa. The team鈥檚 findings show that the same types of clay outcrops can be caused by the solidifying of water-rich magma in a volcanic environment, and don鈥檛 require Earthlike aquatic conditions at all.
The results also correlate to the deuterium-to-hydrogen (D/H) ratio within clays found in Martian meteorites.
鈥淭o crystallize, clays need water but not necessarily liquid water,鈥� said Alain Meunier to the Agen莽e France-Presse (AFP). 鈥淐onsequently, they cannot be used to prove that the planet was habitable or not during its early history.鈥�
Additionally, the clay deposits found on Mars can be several hundred meters thick, which seems to be more indicative of upwelling magma than interactions with water.
鈥淸This] new hypothesis proposes that the minerals instead formed during brief periods of magmatic degassing, diminishing the prospects for signs of life in these settings,鈥� wrote Brian Hynek from the Department of Geological Sciences at the University of Colorado, in response to the paper by Meunier et al. which was published in the September 9 edition of the journal
This does not necessarily mean that all Martian clays weren鈥檛 formed in the presence of water, however. Gale Crater 鈥� where NASA鈥檚 rover is now exploring 鈥� could very well have been the site of a Martian lake, billions of years in the past. Clays found there could have been created by water.
According to Bethany Ehlmann of the California Institute of Technology, co-author of the study, 鈥渢here are particular characteristics of texture鈥� to clays formed under different conditions, and 鈥淕ale is a different flavor of Mars.鈥�
Perhaps Curiosity will yet discover if Gale鈥檚 original flavor was more cool and wet than hot and spicy.
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Inset image: Moruroa Atoll (NASA)聽
Jason Major is a graphic artist from Rhode Island now living and working in Dallas, Texas. He writes about astronomy and space exploration on his blog聽Lights In The Dark, on Universe Today and also on Discovery News.
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