Lunar primitive mantle olivine returned by Chang’e-6
Si‐Zhang Sheng, Shui‐Jiong Wang, Qiuli Li, Shitou Wu, Hao Wang, Jun-Xiang Hua, Zhenyu Chen, J. L. Hao, Bo Zhang, Yongsheng He, Jian‐Ming Zhu
Abstract
The lunar mantle is important for unraveling the Moon's formation and early differentiation processes. Here, we identify primitive lunar olivines in soils returned by the Chang'e-6 mission. These olivines have oxygen isotopic compositions plotting along the terrestrial fractionation line, and are characterized by high forsterite contents up to 95.6, and a broad range of nickel abundances from zero to 682 ppm. While the low-nickel (zero to 251 ppm), forsteritic olivines align with a Mg-suite origin, the most primitive, high-nickel olivines (337 to 682 ppm) have a different origin. They could be either the first olivine crystallized from the Lunar Magma Ocean (LMO) with an Earth-like initial composition, or crystallized from a hitherto unrecognized ultra-magnesian lava produced by extensive melting of the early LMO cumulate. The exposure of these mantle olivines was facilitated by their entrainment in ascending high-Mg lavas and conveyed to the surface at the South Pole-Aitken Basin.