Last year, noted meteorite collector Jay Piatek traveled to Morocco and bought a single stone, less than a pound in weight, that had been discovered in the country some time earlier. When he passed it on to researchers at the University of New Mexico to perform a mineral analysis, they found something unexpected.
The meteor seemed to have originated on Mars, but the rock’s composition didn’t exactly match any of the well-studied meteorites from there found previously. When the researchers compared it to data from soil and rock samples obtained by Curiosity and other recent Martian rovers, though, they realized that rather than originating in the planet’s mantle, as the others had, it appeared to have come from the Martian crust.
Most intriguingly, when they analyzed the basaltic breccia rock even more closely, they discovered it contained a large quantity of water molecules locked in its crystalline structure. While previous studies of Martian meteorites have suggested the presence of water on the red planet, this sample’s analysis, published today in Science, revealed that it contained 10 times more water than any Martian meteorite examined before.
The discovery of the water molecules in the rock at concentrations of 6000 parts per million could indicate the presence of liquid water sometime during Mars’ history. “The high water content could mean there was an interaction of the rocks with surface water either from volcanic magma, or from fluids from impacting comets during that time,” study co-author Andrew Steele of the Carnegie Institute said in a statement.
Apart from the presence of water, the researchers say that information they’ve gleaned over the course of a year-long analysis of the meteor—the first ever linked to the Martian crust—could significantly impact our understanding of the planet’s geology as a whole. The meteorite is primarily composed of chunks of basalt cemented together, indicating that it formed from rapidly cooling lava, likely on the planet’s crust. While we’ve found meteorites from the Moon that match this composition, we haven’t seen anything like it from Mars previously.
Already, the researchers determined that the specimen is roughly 2.1 billion years-old, formed during Mars’ Amazonian epoch, a time period from which we had no previous rock samples. “It is the richest Martian meteorite geochemically,” Steele said. “Further analyses are bound to unleash more surprises.”