New research on Martian meteorites shows evidence that water sufficiently warm enough to support life once existed on Mars.
The study, published this week in the journal Earth and Planetary Science Letters, determined that water temperatures on Mars ranged from 50°C (122°F) to 150°C (302°F). This observation was made using powerful electron microscopes to examine meteorites from Mars that have landed on Earth. Researchers pointed out that microbes on Earth live in such waters, such as those from volcanic thermal springs.
"Rovers on Mars - the Mars Exploration rovers Spirit and Opportunity, and the Mars Science Laboratory rover Curiosity - are studying rocks to find out about the geologic history of the Red Planet," said John Bridges, lead author of the study and reader in planetary science at the University of Leicester Space Research Centre. "Some of the most interesting questions are what we can find out about water, how much there was and what temperature it might have had.
"While the orbiters and rovers are studying the minerals on Mars, we also have meteorites from Mars here on Earth. They come in three different groups, the shergottites, the nakhlites and the chassignites. Of most interest for the question of water on Mars are the nakhlites, because this group of Martian meteorites contains small veins, which are filled with minerals formed by the action of water near the surface of Mars."
Just last week, an analysis of the Martian atmosphere by Mars rover Curiosity corroborated estimates already made from examining Martian meteorites.
On one particular nakhlite meteorite, Bridges and his colleagues discovered that the first newly formed mineral to grow along the walls of the vein was iron carbonate, formed by CO2-rich hot water that cooled and formed clay minerals.
"The mineralogical details we see tell us that there had been high carbon dioxide pressure in the veins to form the carbonates," said Bridges. "Conditions then changed to less carbon dioxide in the fluid and clay minerals formed. We have a good understanding of the conditions minerals form in but to get to the details, chemical models are needed."