The meteoritic debris found among the 1,935.3 grams (68.3 ounces) of lunar regolith sampled by Chang'e 6 belongs to a class of carbon- and water-rich meteorites known as CI (carbonaceous-Ivuna) chondrites. On Earth, these meteorites account for less than 1% of all collected space rocks; their most notable example is the Ivuna meteorite that fell in Tanzania in 1938. Out in space, however, it's a different story, with the asteroids Ryugu and Bennu, visited recently by Japan's Hayabusa2 mission and NASA's OSIRIS-REx, respectively, both displaying similarities to CI chondrites.
And these meteorites may also be relatively abundant on the moon.
Chang'e 6 landed in the South Pole-Aitken Basin on the moon in June 2024 to bring back the first ever sample from the lunar far side. CI chondrites are fine-grained and highly porous, so they break apart easily and react with oxygen and water, which explains why they are so rare on Earth: because they break down or are chemically altered quickly. On the bone-dry moon, however, conditions are suited to preserving the chondrites.
Lin was part of a team led by Jintuan Wang and Zhiming Chen, both of whom also work at the Guangzhou Institute of Geochemistry, who identified unusual olivine-bearing fragments in Chang'e 6's sample. Through mass spectrometry, they found that the fragments contain levels of iron, manganese and zinc that imply that they are not native to the moon; a measurement of oxygen isotopes in the fragments subsequently confirmed that they are CI chondrites.
CI chondrite meteorites typically carry a wealth of volatiles, which are substances such as water and carbon dioxide that can exist as ice in the outer solar system and which have low boiling points. As such, they and other types of carbonaceous chondrites in general are considered as a possible source of water on Earth and the moon.
Source: www.space.com
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