Chang’e-6’s lunar samples have unveiled groundbreaking insights into the moon’s geological history. A collaborative research team from the Institute of Geochemistry of the Chinese Academy of Sciences (IGCAS) and Shandong University has discovered the first evidence of impact-formed hematite and maghemite in lunar soil. This discovery, published in Science Advances, sheds light on the highly oxidized materials present on the moon’s surface, challenging long-held beliefs about the moon’s reduced state.
The research team identified micron-sized hematite grains in the Chang’e-6 lunar soil, confirming their primary lunar origin through advanced spectroscopic techniques. This finding is significant because it suggests that the moon’s surface has experienced localized oxidizing environments during major impact events, driven by the extreme temperatures and desulfurization processes associated with large impacts. These impacts create a transient high-oxygen-fugacity vapor-phase environment, leading to the formation of hematite, which coexists with magnetic magnetite and maghemite.
This discovery has profound implications for our understanding of lunar magnetism and evolution. It challenges the notion that the lunar surface is entirely reduced and provides crucial clues for deciphering the evolution of lunar magnetic anomalies. By linking oxidation processes to the formation of magnetic carrier minerals, this research offers valuable insights into the moon’s geological history and the mechanisms driving large impact events.
The SPA Basin, one of the largest and oldest impact basins in the solar system, served as an ideal natural laboratory for this study. The Chang’e-6 mission’s successful return of soil samples from this basin allowed researchers to explore the highly oxidized substances formed during major impact events. The discovery of impact-formed hematite and maghemite in the Chang’e-6 samples is a significant advancement in our understanding of the moon’s geological processes and the impact of external forces on its surface.