Study of Meteorites Shows Warm Water Existed On Mars

Scientists have long been arguing about the existence of water in Mars. Recently, new evidence has been found by researchers at the University of Leicester and The Open University about Martian water.

They have provided evidence stating that water on Mars is sufficiently warm to support life.

The water temperatures on the Red Planet range from 50C to 150C. Strikingly, microbes on Earth can live in similar waters. The researchers give the example of volcanic thermal springs at Yellowstone Park.

Based on a detailed scrutiny of Mars meteorites on Earth, the researchers have collected data using powerful microscopes in the University of Leicester's Department of Physics and Astronomy. This was followed-up by computer modeling work at The Open University.

Dr John Bridges, reader in planetary science at the University of Leicester Space Research Centre and lead author, said: "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. 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."

The alteration materials were carefully examined by Dr. Bridges and his group. Altogether eight nakhlite Martian meteorites are known, and all have small but significant differences between them and in their alteration minerals.

One of them is Lafayette in which the complete succession of the newly formed minerals is clearly visible. They carefully examined these minerals with the help of an electron microscope and a transmission electron microscope. On conducting an analysis, they noticed that a newly formed mineral growing along the walls of the vein was iron carbonate.

It is assumed that the carbonate was formed by CO2 rich water at around 150C and when the water cooled to 50C, it converted into clay minerals. This formation was followed by an amorphous phase that has the same composition as clay.

During mineral formation, the microbes use the reactions to gain energy and elements essential for their survival.

Dr Bridges added: "The mineralogical details we see tell us that there had been high carbon dioxide pressure in the veins to form the carbonates. 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."

Dr Susanne Schwenzer, postdoctoral research associate in the Department of Physical Sciences at The Open University who previously studied Martian meteorite compositions, said: "Until John's study was finished, I used the findings from orbiters around Mars, and modeled each of the new minerals individually. Those orbiters have found clay on the surface of Mars, but the spatial resolution is very different from the detailed study achieved in the nakhlites. Before we had the detailed study of the nakhlite meteorites, we did not know that carbonates are forming first, followed by the clay. Therefore I was very excited to see the details of the new mineralogical study."

The water conditions on Mars were predicted by combining the data from both the universities.

"The driving force heating the water might have been an impact into the Martian surface." Dr. Bridges explains. "And you only have to look at a map of Mars to see how numerous those are on the Martian surface," Dr. Schwenzer adds.

The study was published in the journal Earth and Planetary Science Letters.