Published in the journal Nature Geoscience, geologists at Arizona State University’s School of Earth and Space Exploration are arguing that magma erupted onto the moon’s surface less than 100 million years ago – nearly a billion years later than previously thought. The new finding suggests that radioactive elements may still be brewing today.
As reported by New Scientist, the moon is thought to have formed about four and a half billion years ago after a collision between Earth and a Mars-sized body. Its crash-birth resulted in a surface molten that lasted for a few hundred million years till its crust solidified. However, magma continued to regularly erupt onto the surface until about three billion years ago, creating vast basaltic plains known as “maria.” Following that, the eruptions discontinued, with the most recent volcanic traits dating to about a billion years ago.
Today, Sarah Braden and colleagues working on the study say that dozens of small rocky formations spotted by cameras on NASA’s Lunar Reconnaissance Orbiter were deposited by lava no more than 100 million years ago—a geologically recent period. Accordingly, the time period the formations date back to correspond to Earth’s Cretaceous period, with some areas perhaps dating back to less than 50 million years.
“This finding is the kind of science that is literally going to make geologists rewrite the textbooks about the moon,“ said John Keller, LRO project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Referred to by scientists as irregular mare patches, the findings show a combination of smooth, deep, rounded mounds near plots of rough, blocky terrain. At less than a third of a mile in size, the features are too small to be seen from Earth. Through its camera, the LRO – which has been orbiting the moon since 2009 – can make out details as small as 50 centimeters across. From the images provided, Braden and team observed 70 unusual areas that stood out from their surroundings, most of which were novelty finds.
The IMPs appear relatively young compared with their setting, suggesting they have experienced no more than 100 million years of influence from space rocks, the study indicates. If so, “the moon was more active in recent history than previously thought possible,” Braden notes. “Young volcanism indicates possibly more magma, or magma at higher temperatures, or magma at shallower depths, or all of the above.”