Moon had volcanoes erupting when dinosaurs were ruling Earth: Study
A groundbreaking study has revealed that the Moon was volcanically active around 120 million years ago, during the era when dinosaurs inhabited Earth. This discovery is based on the analysis of three tiny glass beads, retrieved from the lunar surface by a Chinese spacecraft in 2020. The chemical composition of these beads suggests a much more recent volcanic activity on the Moon than previously believed by scientists.
Chang'e 5 mission's samples contradict previous volcanic activity estimates
The findings, published in the journal Science, challenge earlier assumptions about the Moon's volcanic history. Prior to this study, rock samples from China's Chang'e 5 mission had suggested that lunar volcanoes became inactive around two billion years ago. This new research significantly revises that timeline, indicating active lunar volcanoes existed until approximately 120 million years ago.
Lunar glass beads: First physical evidence of recent volcanism
Julie Stopar, a senior staff scientist at the Lunar and Planetary Institute, described the findings as "a little bit unexpected." She highlighted that while images from NASA's Lunar Reconnaissance Orbiter in 2014 had hinted at more recent volcanic activity, these glass beads are the initial physical evidence supporting this theory. However, she emphasized that further research is needed to confirm their origin.
Study's implications for understanding planetary volcanic activity
The research could potentially enhance our understanding of the duration of volcanic activity on small planets and moons, including Earth. This insight was shared by study co-author He Yuyang from the Chinese Academy of Sciences. The team examined approximately 3,000 lunar glass beads, each smaller than a pinhead, and identified three that showed signs of volcanic origin.
Analytical techniques used to study lunar material
The researchers employed various analytical techniques to examine the lunar material. The glass beads were identified using backscattered electron images and their composition was analyzed with an electron probe microanalyzer. Out of all the beads studied, only 13 had major element compositions similar to those of Apollo volcanic glass beads. Radiometric dating determined that these spherules were approximately 123 million years old, significantly more recent than the last known time of volcanic activity on the Moon.
Spherules contain high proportion of KREEP elements
The three spherules contained a high proportion of what are known as KREEP elements - potassium, rare-earth elements, and phosphorus. These high KREEP abundances can be sources of radiogenic heating — the heat generated by radioactive decay. This heating can be significant as around half of Earth's internal heat is from radioactive decay. On the Moon, radiogenic heating could, in theory, produce pockets of localized volcanism.
