Moon Rocks Brought From the Far Side Confirm Ancient Volcanic Activity

Researchers have revealed insights into the Moon's far side, analysing samples retrieved by China's Chang'e-6 mission. This mission was the first time when nearly 2kg of geological samples from the far side of the Moon was brought back to the Earth. The findings, detailed in two separate studies published on November 15, in Science and Nature, provide a comprehensive view of volcanic activity on the Moon that persisted for billions of years.

Decoding Lunar Dust and Lava Grains

Dr. Qiu-Li Li, a researcher at the Chinese Academy of Sciences in Beijing and co-author of an independent study published in the Nature journal, highlighted the importance of the findings, explaining that they shed light on prolonged volcanic activity and distinct mantle sources on the lunar far side. The mission, China's second to the far side after Chang'e-4 in 2019, landed in the ancient South Pole-Aitken Basin, formed approximately four billion years ago by a massive meteor impact.

The samples collected comprised fine dust particles ranging from 1 to hundreds of micrometres in size. According to Dr. Yi-Gang Xu, petrologist at the Chinese Academy of Sciences in Guangzhou and co-author of another independent study published in the Science journal, these particles reflect a mixture of materials from various geological eras. The continuous bombardment by micrometeorites and solar particles over time has contributed to the formation and dispersal of such dust across the Moon.

Isotopic analysis revealed that some grains originated from lava flows dated to around 2.83 billion years ago. Researchers working on the Nature study also identified lava grains as old as 4.2 billion years, underscoring the Moon's extensive volcanic history.

Implications for Lunar Evolution

The studies collectively confirm that the Moon experienced sustained volcanic activity long before transitioning into the largely inactive state observed today. These findings contribute significantly to the understanding of lunar evolution and planetary geology.

By returning and analysing these unique samples, Chang'e-6 has added valuable knowledge about the Moon's far side, marking a significant step forward in lunar exploration.