Recent findings from China’s Chang’e 5 mission have transformed our understanding of lunar geology.
The Chang’e 5 mission, which returned lunar soil samples to Earth in December 2020, has provided groundbreaking insights into the moon’s volcanic history. Analysis of these samples, specifically three tiny glass beads, reveals evidence of volcanic eruptions as recent as 123 million years ago, with a margin of error of about 15 million years. This finding is significant because it suggests that the moon may have experienced volcanic activity far more recently than the previously believed end of lunar volcanism.
Historically, the moon’s volcanic activity was thought to have ceased around 3 to 3.8 billion years ago, when the dark maria—vast volcanic plains—formed on its surface. However, the Chang’e 5 samples indicate that volcanic processes could have continued much later. The three glass beads, out of a total of 3,000 examined, were found to be volcanic in origin, formed by magma fountains rather than asteroid impacts.
Bi-Wen Wang and Qian Zhang, researchers from the Institute of Geology and Geophysics at the Chinese Academy of Sciences, detailed their findings in a recent paper. “Uranium-lead dating of the three volcanic glass beads shows that they formed 123 million, ±15 million, years ago,” they reported.
This technique, which measures the radioactive decay of uranium into lead, confirms the relatively young age of the beads and, by extension, the recent volcanic activity.
Supporting this new evidence are features known as irregular mare patches (IMPs), which NASA’s Lunar Reconnaissance Orbiter (LRO) observed in 2014. These smooth, round mounds found on volcanic plains appear to be less than 100 million years old, further suggesting recent volcanism. Although earlier models predicted the moon’s interior would have cooled long ago, the new findings challenge this view, raising questions about the moon’s thermal evolution.
Wang and Zhang’s team proposed that high concentrations of rare earth elements and thorium in the volcanic glass beads might indicate localized heat generation in the moon’s mantle. These elements, including potassium, phosphorus, and lanthanum, can produce heat through radioactive decay, potentially driving modest volcanic eruptions.
The possibility of current volcanic activity on the moon raises intriguing questions. Transient lunar phenomena (TLP), or ghostly colored hazes observed by amateur astronomers, have been attributed to potential volcanic outgassing, though such claims remain controversial.
