Scientists from Case Western Reserve University, Carnegie Institution for Science and Brown University discovered water along with volatile elements in lunar magma inside crystals trapped inside tiny volcanic glass beads returned to Earth by Apollo 17, a Case Western release said Thursday.
The orange-colored beads, no bigger than a period on a page, came from deep inside the moon during volcanic eruptions.
"These samples provide the best window we have to the amount of water in the interior of the moon," James Van Orman, Case Western professor of geological sciences, said. "The interior seems to be pretty similar to the interior of the Earth, from what we know about water abundance."
The concentrations of water and volatile elements, including fluorine, chlorine and sulfur, in lunar magma are almost identical to concentrations in solidified magma from primitive terrestrial mid-ocean ridges on Earth, the researchers said.
The same team, in a study three years ago led by Alberto Saal, a professor of geological sciences at Brown University, found the first evidence of the presence of water in lunar volcanic glasses.
"The bottom line," Saal said, "is that in 2008, we said the primitive water content in the lunar magmas should be similar to lavas coming from the Earth's depleted upper mantle. Now, we have proven that is indeed the case."