Researchers confirm volcanic activity on the Moon 120 million years ago

Researchers confirm volcanic activity on the Moon 120 million years ago
by Simon Mansfield
Sydney, Australia (SPX) Sep 06, 2024

Geological evidence has long shown that volcanic activity occurred on the Moon, but the duration of this activity has remained uncertain. A recent discovery by Prof. LI Qiuli's lab at the Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS), has provided new insights into the Moon's volcanic history. The team identified three volcanic glass beads from lunar soil samples collected by China's Chang'e-5 mission, demonstrating that they were formed around 123+/-15 million years ago. This discovery marks the youngest lunar volcanic activity confirmed through radioisotope dating.

The research findings have been published in the journal 'Science'.

Previously, lunar basalt samples returned to Earth from the Apollo and Luna missions, as well as lunar meteorites, indicated that basaltic volcanic activity on the Moon persisted until at least 2.9-2.8 billion years ago. However, newer analysis of samples from the Chang'e-5 mission revealed that this activity continued until at least 2 billion years ago.

Remote sensing studies have suggested the possibility of even younger volcanic activity, during the late Copernican era (less than 800 million years ago). However, these observations lacked precise dating, and the potentially younger basaltic extrusions covered small, limited regions with no physical samples available for analysis.

Volcanic activity, particularly eruptions of gas-rich magma, can produce magma fountains that create submillimeter-sized glass beads. These beads may spread across wide areas of the lunar surface and be further distributed by impacts. Such volcanic glasses may already be present as trace components in existing lunar soil samples.

In their study, supervised by Profs. LI Qiuli and HE Yuyang, graduate student WANG Biwen and postdoctoral researcher ZHANG Qian examined approximately 3,000 glass beads from lunar soil samples. They successfully identified three volcanic glass beads, based on detailed analyses of their textures, major- and trace-element compositions, and sulfur isotope characteristics.

The sulfur isotope data (d34S values) of the volcanic glass beads were found to differ significantly from that of glass beads created by impacts. This distinction provided a reliable method to separate volcanic glasses from impact-induced ones. Uranium-lead dating of the three volcanic glass beads confirmed their formation at 123+/-15 million years ago.

This finding offers concrete evidence of 120-million-year-old volcanic activity on the Moon. The discovery of such recent volcanism on a small celestial body like the Moon challenges assumptions about its thermal evolution, suggesting that it retained enough internal heat to sustain volcanic activity until a relatively late stage. The results contribute valuable information for refining geophysical models of the Moon's internal thermal history.

The study was conducted in collaboration with researchers from Nanjing University and the State University of New York at Albany, and the samples used were provided by the China National Space Administration.

Research Report:Returned samples indicate volcanism on the Moon 120 million years ago