The Chang’e-5 mission landed in the Mons Rümker region of the Moon’s northern Oceanus Procellarum and returned 1,731 kg of lunar regolith.
Recognition of exotic clasts (ie, materials not locally derived from Chang’e-5) could provide essential information about the lithological diversity and regolith formation process in the young region of the Moon.
Recently, Dr. ZENG Xiaojia, Prof. LI Xiongyao and Prof. LIU Jianzhong from the Institute of Geochemistry of the Chinese Academy of Sciences (IGCAS) identified seven exotic igotic clasts in Chang’e-5 samples from more than 3,000 Chang regolith particles it’s 5.
This paper was published in the journal Nature Astronomy.
Specifically, the seven exotic clasts identified are: a high-Ti fragment, a low-Ti basalt, olivine-pyroxenite, a magnesian anorthosite, an evolved lithology, a Mg-rich olivine fragment, and a glass pearl pyroclastic.
Clues to the process of regolith formation in the young region of the Moon
The researchers associated these exotic ion clasts with impact ejected material from other regions of the Moon located more than 50-400 km from the Chang’e-5 large unit.
By comparison with lunar rocks from the US Apollo mission, the researchers found that three exotic igneous clasts in the Chang’e-5 regolith showed unusual petrological and compositional characteristics.
The high-Ti vitrophyritic fragment showed a unique mineralogy among lunar basalts, possibly representing a new type of lunar basalt.
The magnesian anorthosite clast was not observed in the Apollo samples. In addition, it provides evidence that magnesian anorthosite is also an important component of the near-side lunar crust.
How might future missions help the discovery?
Pyroclastic glass records a compositionally unique volcanic eruption on the Moon, he writes EurekAlert.
This study was the first to obtain exotic igneous lithologies from the Moon. These findings will provide basic information for modeling the provenance of the regolith in the young lunar marine unit.
In addition, the identification of unusual lunar rocks in the Chang’e-5 sample provides evidence that the lithological components and magmatic activities of the lunar crust are in fact more diverse than previously thought.
This research suggests that there are still unknown geological units on the Moon, which may help plan future lunar exploration missions.