Long-term reduced lunar mantle revealed by Chang’e-5 basalt

作者：Huijuan Zhang, Wei Yang, Di Zhang, Heng‐Ci Tian, Renhao Ruan, Sen Hu, Yi Chen, Hejiu Hui, Yanhao Lin, Ross N. Mitchell, Di Zhang, Shitou Wu, Lihui Jia, Lixin Gu, Yangting Lin, Xian‐Hua Li, Fu‐Yuan Wu · 发表于：Nature Communications · 年份：2024 · DOI：10.1038/s41467-024-52710-x · 被引用次数：17 · 研究领域：Planetary Science and Exploration、Astro and Planetary Science、Geological and Geochemical Analysis

The redox state of a planetary mantle affects its thermal evolution. The redox evolution of lunar mantle, however, remains unclear due to limited oxygen fugacity (fO2) constraints from young lunar samples. Here, we report vanadium (V) oxybarometers on olivine and spinel conducted on 27 Chang’e-5 basalt fragments from 2.0 billion years ago. These fragments yield an average fO2 of ΔIW -0.84 ± 0.65 (2σ), which closely aligns with the Apollo samples from 3.6–3.0 billion years ago. This temporal uniformity indicates the lunar mantle remained reduced. This observation reveals that the processes responsible for oxidizing mantles of Earth and Mars either did not occur or had negligible oxidizing effects on the Moon. The long-term reduced mantle may lead to a distinctive volatile degassing pathway for the Moon. It could also make the lunar mantle more difficult to melt, preventing internal heat dissipation and consequently resulting in a slow cooling rate. The lunar mantle may have remained reduced, according to the oxygen fugacity of 2.0 Ga Chang’e-5 basalt that is similar to 3.6 − 3.0 Ga Apollo basalts and pyroclastic glasses.