【Latest Discovery and Innovation】
Science and Technology Daily, Kunming, November 27 (Reporter Zhao Hanbin) The reporter learned from the Institute of Geochemistry, Chinese Academy of Sciences on the 27th that for the sulfide particles in the lunar soil powder collected by the Chang'e-5 surface, the Li Yang research team of the institute recently launched an in-situ Micro-area analysis confirmed for the first time the existence of submicron magnetite of impact origin in lunar soil.
Relevant results were published in the international journal Nature Communications.
Magnetite usually involves major scientific issues such as ancient magnetic fields and extraterrestrial life, so it has attracted much attention from scholars in the field of planetary science.
The Chang'e-5 mission successfully brought back 1.731 kilograms of lunar soil materials from the young lunar sea basalt unit. Although the sample analysis results showed that almost all of the Chang'e-5 lunar soil came from local materials, there are still a small number of lunar soil particles from Due to the sputtering of large impact craters, the lunar soil also most likely retains the initial reaction information of the lunar surface impact process.
Through scanning electron microscopy and transmission electron microscopy, the research team found spherical iron sulfide particles with a diameter of about 2 microns in the fine-grained lunar soil of Chang'e-5, which generally have the characteristics of dissolved oxygen and contain a large amount of submicron magnetite. and pure metallic iron particles, while iron oxide particles embedded in spherical iron sulfide particles, were identified as submicron-sized magnetite crystals.
In addition, the typical characteristics of silicate gasification, oxygen dissolution, and equilibrium precipitation of magnetite and metallic iron particle phases imply that the dissolved oxygen iron sulfide particles in the Chang'e-5 lunar soil were a large-scale impact event on the lunar surface product.
Studies have shown that the sulfides on the lunar surface will undergo complex gas-liquid reactions during the impact process, so that the zero-valent iron dissolved into the sulfides will undergo eutectoid reactions to generate submicron-sized magnetite and elemental metallic iron.
Since the Apollo spacecraft era, people's understanding of the ferromagnetic minerals on the moon has been dominated by metallic iron.
On the basis of previous studies, this study provided another important ferromagnetic mineral on the lunar surface—magnetite, and effectively established the relationship between the formation of ferromagnetic minerals and impact events, so it is of great significance.