Abstract
Lunar materials are overall more reducing compared with their terrestrial counterparts,but the mecha-nism remains to be elucidated.In this study,we present a possible explanation for the changes in redox state of the lunar regolith caused by impact events,based on our investigations of the impact glass beads from Chang'e-5 mission.These glass beads contain iron metal grains and show concentration gradients of FeO and K2O(with or without Na2O)from their rims to centers.The compositional profiles exhibit error-function-like shapes,which indicates a diffusion-limited mechanism.Our numerical modeling results suggest that the iron metal grains on the surface of the glass beads were generated through the reduction of FeO by elemental K and(or)Na produced during the impact events.Meanwhile,the iron metal grains inside the bead may have formed due to oxygen diffusion driven by redox potential gradients.Furthermore,our study suggests that impact processes intensify the local reducing conditions,as evi-denced by the presence of calcium sulfide particles within troilite grains that coexist with iron metal grains on the surface of the glass beads.This study provides insights into the oxygen diffusion kinetics during the formation of iron metal spherules and sheds light on the changes in redox conditions of lunar materials caused by impact events.
基金项目
China National Space Administration(CNSA)for providing the CE-5 lunar sample(CE5C0800YJFM00101GP)
国家自然科学基金(41773052)
国家自然科学基金(41973058)
国家自然科学基金(42003054)
国家自然科学基金(42073062)
中国博士后科学基金(2020M680155)
中国科学院战略规划重点项目(XDB 41000000)
中国科学院前沿科学重点研究计划(ZDBS-SSW-JSC007-10)
Preresearch project on Civil Aerospace Technologies funded by CNSA(D020201)
NETL
NSTL
万方数据