On July 13, reporters learned from the Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS) that a research team led by Professor Li Jinhua, using Chang'e-6 lunar soil samples, has conducted a detailed analysis of various magnetic minerals in the lunar regolith and how their unique magnetic properties are generated and preserved. This work has solved the long-standing puzzle of why the lunar far-side crust has a weak magnetic field while the soil exhibits strong magnetism. The findings were published online in Nature Communications.

In this latest study, the team employed multiple cutting-edge microscopic analysis techniques and identified two distinct types of magnetic-carrying particles with different origins in the Chang'e-6 lunar soil. Additionally, they discovered at least three kinds of metallic iron particles formed through "secondary alteration" processes. The origin and physicochemical properties of these magnetic carriers determine the different magnetic records and stability they leave in the regolith. Given that the Chang'e-6 landing site has a weak crustal magnetic field yet contains abundant strongly magnetic minerals, the study further infers that the strong magnetic anomalies at the northern rim of the South Pole–Aitken (SPA) basin are likely due to thicker accumulations of ejecta containing highly magnetizable exogenous metallic material.

"This research not only helps explain the magnetic mystery of the lunar South Pole–Aitken basin but also provides important insights for future studies of magnetic minerals and magnetic field evolution in samples from asteroids, Mars, and other celestial bodies," said Academician Pan Yongxin of IGGCAS. The work is of great significance for understanding the history of the Moon's magnetic field and the surface modification processes on the Moon.