Discovery of a new lunar mineral rich in water and ammonium in lunar soils returned by Chang’e-5 mission

[Marco E. Ciriotti]

Prossima pubblicazione.

Referenza:
▪ Jin, S., Hao, M., Guo, Z., Yin, B., Ma, Y., Deng, L., Chen, Xu, Song, Y., Cao, C., Chai, C., Ma, Y., Guo J., Chen, X. (2023): Discovery of a new lunar mineral rich in water and ammonium in lunar soils returned by Chang’e-5 mission.

Abstract:
The origin and distribution of lunar water are among the most important issues in understanding the earth-moon system. After more than half a century of laboratory research and remote detection, only hydroxyl contained minerals and lunar ice (H2O) are identified. Here we report the discovery of a hydrous mineral (NH4)MgCl3·6H2O in the lunar soil returned by Chang’e-5 mission, which contains ~417,000 parts per million H2O. The determined structure and composition are similar to novograblenovite—a terrestrial fumarole mineral formed by reaction of hot basalt in water-rich volcanic gases, whereas the measured isotope composition δ37Cl reached 20.4 ‰, a high value that only found in lunar minerals. We rule out the possibility that this hydrate originated from terrestrial contaminants or rocket exhaust through analysis of its chemical, isotopic compositions as well as the formation conditions. Our finding indicates that water can exist on some parts of the sunlit Moon in the form of hydrate compounds. Moreover, this hydrate is rich in ammonium, providing new information in understanding the origin of the Moon.