China’s Chang’e-6 Discovers Rare Meteorite Fragments on Moon

China’s Chang’e-6 mission has yielded a groundbreaking discovery: lunar dust containing tiny fragments from a rare type of meteorite. This finding, which may provide insights into the origins of water on Earth, marks the first confirmed instance of such debris found on the Moon. Researchers from the Chinese Academy of Sciences identified microscopic grains from an Ivuna-type carbonaceous chondrite, known as a CI chondrite, in the samples returned from the mission.

CI chondrites are distinguished by their high water content, with up to 20% of their mass composed of water combined with hydrated minerals. These meteorites are vital for understanding how water and other essential materials might have been delivered to both Earth and the Moon. Despite their significance, CI chondrites are incredibly fragile. Due to their soft and porous nature, they often disintegrate upon entering Earth’s atmosphere, which is why less than 1% of meteorites found on our planet belong to this category.

The Chang’e-6 mission, which returned samples from the Moon’s far side, faced unique challenges in identifying these rare fragments. Unlike Earth, the Moon lacks a protective atmosphere. However, objects impacting the lunar surface do so at extremely high speeds, often resulting in their destruction. Yet, scientists believed that the South Pole-Aitken basin, a region known for its history of impacts, offered a promising location for investigating ancient meteorites.

Research Methodology and Findings

Led by geochemists Jintuan Wang and Zhiming Chen, the research team meticulously examined the Chang’e-6 samples. They focused on a specific area known as the Apolo crater, located within the vast South Pole-Aitken basin, which covers nearly a quarter of the Moon’s surface. The team analyzed approximately 5,000 tiny fragments, known as clastos, which contained olivine— a mineral commonly found in volcanic rocks and meteorites.

The researchers carefully set aside clastos that exhibited olivine and polished them for detailed analysis using advanced techniques, including scanning electron microscopy and secondary ion mass spectrometry. Out of the examined fragments, seven clastos showed chemical characteristics consistent with CI chondrites. Their unique porphyritic textures, with olive crystals embedded within a vitreous matrix, confirmed their origins.

Comparative analyses of silicon and oxygen isotopes, as well as iron-to-manganese ratios, indicated that these seven clasts did not fit the established ranges for lunar or terrestrial rocks. Instead, their elemental signatures aligned with those of CI chondrite meteorites, suggesting that the material likely originated from an asteroid that impacted the Moon. Upon impact, the meteorite melted and cooled rapidly, preserving its original chemical composition.

Implications for Future Research

This discovery holds significant implications for our understanding of the solar system’s early history. The researchers emphasized that their methodology could be applied to future studies of lunar rocks and other returned samples. “Given the rarity of CI chondrites in Earth’s meteorite collection, our integrated methodology for identifying exogenous materials in lunar and potentially other returned samples offers a valuable tool for reassessing chondrite proportions in the inner Solar System,” the team noted.

The Chang’e-6 mission continues to enhance our understanding of not only the Moon but also the broader context of planetary formation and the distribution of water in the solar system. As scientists continue to analyze these lunar samples, further revelations about the origins of water on Earth and its implications for life may soon emerge.