June 22, 2012
More Evidence Of Water On Mars
Is there water on other planets?
Two Martian meteorites known to have originated from the Red Planet were recently analyzed by scientists. The amount of water they found is considerably larger than what was previously thought to have been on Mars.
Knowing this not only changes what we know about the Red Planet, but also raises questions about how the water got there and if there is a probability that Mars could have supported life.
The research was led by former Carnegie postdoctoral scientist Francis McCubbin, now at the University of New Mexico. The analysis was performed by Carnegie Institution investigator Erik Hauri and team and is published in the journal Geology.
The fairly young meteorites are called shergottite meteorites and originated by partial melting of the Martian mantle – the layer under the crust – and crystallized in the shallow subsurface and on the surface. They came to Earth after being ejected from Mars approximately 2.5 million years ago.
The scientists used meteorite geochemistry, which tells them quite a lot about the geological development that the planet underwent.
“We analyzed two meteorites that had very different processing histories,” explained Hauri. “One had undergone considerable mixing with other elements during its formation, while the other had not. We analyzed the water content of the mineral apatite and found there was little difference between the two even though the chemistry of trace elements was markedly different. The results suggest that water was incorporated during the formation of Mars and that the planet was able to store water in its interior during the planet´s differentiation.”
According to the mineral´s water makeup, scientists calculate that the Martian source from which the samples originated contained between 70-300 ppm (parts per million) water. Compared to what is on Earth, rocks include 50-300 ppm water. Hauri and team were able to settle on these values with new techniques and new values they developed that can measure water in apatite using a technology called secondary ion mass spectrometry (SIMS).
“There has been substantial evidence for the presence of liquid water at the Martian surface for some time,” Hauri said. “So it´s been puzzling why previous estimates for the planet´s interior have been so dry. This new research makes sense and suggests that volcanoes may have been the primary vehicle for getting water to the surface.”
McCubbin concluded, “Not only does this study explain how Mars got its water, it provides a mechanism for hydrogen storage in all the terrestrial planets at the time of their formation.”