Washington: Scientists have apparently discovered a new type of rock on the lunar surface, which was spat up by a style of volcano never before seen on the moon.
New data from NASA`s Lunar Reconnaissance Orbiter (LRO) has suggested that the new volcano type oozed thicker lava rich in silica over a light, arrowhead-shaped patch of the moon roughly 18 miles (30 kilometres) across, called Hansteen Alpha.
Until now, scientists had believed the moon was made of two basic types of rock: dark basalt and light, calcium-rich feldspar. Both would have come from volcanoes spewing relatively runny basaltic lava.
The new type of moon volcano is now extinct as the last time it oozed any lava was two billion years ago at best, said Timothy Glotch of Stony Brook University and co-author of a new paper describing the find.
Scientists found the volcano using LRO`s Diviner instrument, which looks at light being reflected from the moon`s surface in mid- to far-infrared wavelengths.
The LRO scientists think pockets of the newfound silica-based rock must have been created as basaltic magma deep in the moon melted some of the silica-containing deep crust.
The new rock`s signature was also found inside and around some lunar craters, suggesting that when a comet or asteroid hit the moon, the impact threw up chunks of the underground silica-rich rock.
It`s even possible some of this new moon material is already here on Earth.
"If you look through the material the Apollo mission brought back, we see tiny grains of granite-there might be a gram here or a gram there. People always wondered where those things came from," National Geographic News quoted Glotch as saying.
"Here we`re talking about whole volcanoes made of this rock. Sampling this other rock type would give us a completely different picture of the moon from the Apollo samples," he added.