A recent analysis of shergottite meteorites has revealed that the Red Planet contains about as much water under the surface as Earth does. This estimate is significantly higher than what experts first calculated for Mars, and indicates a very water-rich history for our neighboring world.
The study refers to water trapped inside the Martian mantle, deep under the surface. On Earth, still a geologically active world, the mantle is located some 30 to 50 kilometers (18 to 30 miles) beneath the surface. Previously, it was thought that ours was the only planet to feature water in its interior.
The new study, which focused on meteorites that were produced directly from the Martian mantle following large asteroid collisions, proves that assertion to be false. The two shergottites used in this study found their way here after traveling through the solar system for millions of years.
According to researchers at the Carnegie Institution for Science (CIS), the investigation has important implications for our understanding of Mars' geological history, as well as for figuring out how water got on the surface of the planet in the first place.
But perhaps the most important implication is that the Red Planet may have at one point been able to support life as we know it, says Francis McCubbin, who led the work while a CIS postdoctoral scientist. He is now based at the University of New Mexico.
The actual samples were tested and analyzed by Erik Hauri, an investigator at CIS, and his team. Details of the work appear in the June 15 online issue of the esteemed journal Geology, which is published by The Geological Society of America.
The shergottites in the research were found to be around 2.5 million years old, which means that they are, geologically speaking, very young. “We analyzed two meteorites that had very different processing histories,” Hauri says.
“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,” he adds.
“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,” the investigator goes on to say.
The upper mantle on Earth, Hauri says, contains approximately 50-300 ppm (parts per million) water. The study showed that the Martian mantle contains 70 to 300 ppm water. What this suggests is that water may have made its way to the surface primarily through volcanic activity.
“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,” Hauri concludes, quoted by Astrobiology Magazine