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

China’s Chang’e-6 mission has made a groundbreaking discovery on the Moon, unveiling tiny fragments of a rare meteorite type that could shed light on the origins of water on Earth. The lunar dust samples collected from the Moon’s far side contained microscopic grains from an Ivuna-type carbonaceous chondrite, a meteorite known for its high water content. This find marks the first confirmed presence of such meteorite debris on the Moon.

The samples were analyzed by a team of geochemists from the Chinese Academy of Sciences, led by Jintuan Wang and Zhiming Chen. Their research indicates that even delicate and water-rich asteroids can leave behind evidence preserved in lunar soil, offering insights into the early history of the solar system that would likely be destroyed on Earth.

Significance of CI Chondrites

CI chondrites are considered among the most unusual meteorites due to their composition. They are rich in water and volatile elements, with as much as 20% of their mass consisting of water bound within hydrated minerals. Understanding these meteorites is crucial for unraveling how water and other essential materials may have been delivered to both Earth and the Moon.

These meteorites are exceptionally fragile. Their soft and crumbly nature makes them prone to destruction when entering Earth’s atmosphere at high speeds. Consequently, less than 1% of the meteorites found on Earth belong to this group. While one might think the absence of an atmosphere on the Moon would facilitate the preservation of such meteorites, the reality is that impacts on the lunar surface occur at immense velocities, often leading to the evaporation or complete destruction of the incoming rocks.

Methodology in Sample Analysis

Despite these challenges, the research team meticulously examined the material returned by Chang’e-6. The samples were taken from the Apolo crater, situated within the vast South Pole-Aitken basin, which is a prime location for studying ancient meteorites due to its history of impact events.

The team scrutinized approximately 5,000 tiny fragments identified as containing olivine, a mineral commonly found in volcanic rocks and meteorites. After isolating several fragments with olivine, the researchers polished these samples for in-depth analysis using advanced techniques such as scanning electron microscopy and secondary ion mass spectrometry.

From their candidates, the team successfully identified seven clasts that exhibited chemical characteristics aligning with those of CI chondrites. These fragments displayed porphyritic textures, featuring olive crystals embedded in a vitreous matrix.

To confirm their findings, the researchers compared the isotopic patterns of silicon and oxygen, as well as the iron-to-manganese ratios and concentrations of nickel and chromium oxides. The clasts did not fall within established ranges for lunar and terrestrial rocks, but their unique signatures matched those of CI chondrite meteorites. This suggests that the material likely originated from a CI chondrite asteroid that collided with the Moon, melted upon impact, and cooled rapidly, preserving its original chemistry.

The findings from the Chang’e-6 mission not only enhance our understanding of lunar geology but also provide valuable tools for future lunar research. The scientists noted that their methodology could be instrumental in analyzing Moon rocks and other samples returned from space missions. As they stated, “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.”

This significant discovery opens new avenues for understanding the delivery of water and organic materials in our solar system, marking a crucial step in unraveling the mysteries of planetary formation and the potential for life beyond Earth.