London: Scientists have found a small volcanic province on the far side of the Moon, indicating that it is more geologically active than was believed.
The hot spot is a concentration of a radioactive element thorium sitting between the very large and ancient impact craters Compton and Belkovich that was first detected by Lunar Prospector’s gamma-ray spectrometer in 1998.
Recent observations, made with the powerful Lunar Reconnaissance Orbiter (LRO) optical cameras, have revealed geological features diagnostic not just of volcanism but also of much rarer silicic volcanism.
“That’s very unusual,” says Bradley Jolliff, of Washington University in St. Louis, who led the team that analyzed the LRO images.
“There are only about a half dozen other features on the Moon that are thought to be silica-rich, because the Moon, unlike the Earth, does not reprocess rock materials in a way that concentrates silica.”
Jolliff and his team can’t yet be sure and are reluctant to speculate, but they suspect the newly discovered volcanic province might be much younger than most of the volcanic features in the Procellarum KREEP Terrane.
“But,” he says, “the Moon may still have a molten outer core generating pulses of heat like the Hawaiian volcanic chain.
The GRAIL mission that will launch later this year might confirm this idea.
The study has been published in the journal Nature Geoscience.