Data for "First Discovery of Impact-Induced Vapor Deposition of Cu Metal, FeCo Alloy and Digenite from Chang'e-5 Lunar Soil"

Impact-induced vapor deposition is an important space weathering process that can alter or reconstruct the chemical composition of the surface materials on the Moon and other airless celestial bodies. Some phenomena associated with meteorite impact have been reported in lunar and asteroid samples, such as nanoparticles of Fe metal, the mineral hapkeite (Fe2Si) and digenite (Cu9S5). Previous studies have focused mainly on silicate minerals, while sulfides were less investigated. Using the electron microanalysis technology, we first discovered the coexistence of Cu metal, FeCo alloy and Cu-sulfide (digenite) layer on the surface of troilite in a Chang'e-5 basalt clast. The thin digenite layer (50~100 nm) on the surface of troilite and mineral interstice indicates the origin of impact-induced vapor deposit. Both Cu and Co are probably exogenous since no Cu- or Co-bearing components were detected in the sample. This indicates that Cu metal, FeCo alloy and digenite layer are all the products of shock-induced vapor deposition.

冲击诱导气相沉积（Impact-induced vapor deposition）是一类重要的空间风化过程，可改变乃至重塑月球及其他无大气天体表面物质的化学成分。科研人员已在月球与小行星样品中报道过诸多与陨石冲击相关的现象，例如金属铁纳米颗粒、矿物哈普基石（hapkeite，Fe₂Si）以及蓝辉铜矿（digenite，Cu₉S₅）。过往研究多聚焦于硅酸盐矿物，对硫化物的探讨则相对较少。本研究借助电子显微分析技术，首次在嫦娥五号（Chang'e-5）玄武岩碎屑的陨硫铁（troilite）表面观测到金属铜、铁钴合金（FeCo alloy）与铜硫化物（蓝辉铜矿，digenite）层的共存现象。陨硫铁表面与矿物间隙处的薄蓝辉铜矿层（厚度50~100 nm），表明该产物源自冲击诱导气相沉积。由于样品中未检测到含铜或含钴组分，铜与钴大概率属于外源物质。这表明金属铜、铁钴合金与蓝辉铜矿层均为冲击诱导气相沉积的产物。