New evidence collected by China’s Chang’e-5 lunar rover suggests that the moon experienced volcanic activity as recently as 120 million years ago. Previous studies of lunar rocks collected in the 1970s showed evidence of widespread volcanism on the moon dating back billions of years. However, this new evidence is the first to indicate the presence of lunar volcanic activity in the relatively recent past.
Named after the Chinese moon goddess Chang’e, the rover mission was the first to collect and return lunar samples to Earth since the Soviet-era Luna 24 mission brought the last lunar samples home for analysis in 1976.
After landing on the moon in 2020, the Chang’e-5 mission has made a number of significant scientific discoveries. In 2022, The Debrief covered that mission’s confirmation of water in those returned samples, which supported an initial finding made by the rover when it was still operating on the moon.
More recently, Chinese scientists analyzing the returned lunar samples found the clear presence of several silica-based minerals, as well as a whole new mineral that has since been named Changesite-(Y).
According to a newly published study, the discovery of volcanism on the moon as recently as 120 million years ago was not simple. First, the team had to sort through thousands of tiny glass beads in the returned regolith to see if any showed signs of volcanism.
“We investigated ~3000 glass beads in lunar soil samples collected by the Chang’e-5 mission,” they write, “and identified three as having a volcanic origin on the basis of their textures, chemical compositions, and sulfur isotopes.”
These tests set the three glass beads apart from the others, which study authors Bi-Wen Wang, Qian W.L. Zhang, and colleagues say were likely the product of meteorite impacts. The evidence of these powerful impacts covers the entire lunar surface with craters of all sizes, meaning these types of impact-generated tiny glass beads are more common than any that might have a volcanic origin.
Next, the team employed a type of radiometric dating known as Uranium-lead dating to determine the age of the volcanic glass beads. These tests revealed that these tiny glass beads were formed much more recently, unlike previous evidence of volcanism on the moon found within samples collected by the Apollo and Luna missions of the 1970s.
Specifically, the older samples showed widespread volcanic activity from 4.4 billion to 2.0 billion years ago, whereas the new samples were dated to approximately 120 million years ago, give or take 15 million years.
This latest finding showed that at least some volcanic activity on the moon was still occurring relatively recently, cosmologically speaking. The team believes this recent volcanic activity was more localized than the widespread volcanism that happened during the formative stages of Earth’s only natural satellite.
Additional testing of the volcanic glass beads revealed “a high abundance” of potassium, phosphorus, and some rare-earth elements. The latter, known as KREEP elements, can create a type of radioactive heating that the researchers may have been part of the volcanic cycle on the moon 120 million years ago. This includes melting the Moon’s mantle so small amounts of magma can “erupt” to the surface.
“We measured high abundances of rare earth elements and thorium in these volcanic glass beads, which could indicate that such recent volcanism was related to local enrichment of heat-generating elements in the mantle sources of the magma,” they write.
Although the evidence for volcanism on the moon is still being tested, the Changee-5 researchers believe that their evidence shows that there was volcanic activity on the moon as recently as 120 million years ago. If confirmed, this evidence could help rewrite the moon’s geological history.
The study, “Returned samples indicate volcanism on the Moon 120 million years ago,” was published in the journal Science.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.