KREEP-rich breccia in Chang'E-5 regolith and its implications

作     者：Aoxin MEI Yun JIANG Shiyong LIAO Jinting KANG Fang HUANG Weibiao HSU 

作者机构：CAS Key Laboratory of Planetary SciencesPurple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Center for Excellence in Comparative PlanetologyChinese Academy of SciencesHefei 230026China CAS Key Laboratory of Crust-Mantle Materials and EnvironmentsSchool of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Institute of Deep Space SciencesDeep Space Exploration LaboratoryHefei 230026China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2023年第66卷第11期

页      面：2473-2486页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0705[理学-地理学] 0704[理学-天文学] 

基　　金：funded by the National Key Research and Development Program of China(Grant No.2021YFA0716100) the National Natural Science Foundation of China(Grant Nos.41973060,42173044,42241146 and 42273007) the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB 41000000) the preresearch Project on Civil Aerospace Technologies(Grant Nos.D020202 and D020302) the Key Research Program of the Chinese Academy of Sciences(Grant No.ZDBS-SSW-JSC007)。 

主　　题：Chang'E-5 Regolith breccia Impact glasses KREEP Mare basalts 

摘      要：Lunar breccias provide crucial insights into the lithological diversity,shock processing and evolution of the lunar crust.Here,we report a unique regolith breccia(CE5C0000YJYX070GP,hereafter CE5C)returned from the Chang E-5(CE-5)mission.CE5C is one of the largest CE-5 breccias with a wide variety of lithologies,dominated by basaltic and mineral fragments as well as impact-melted clasts(including mid-Ti glasses,high-Al glasses,and crystal-bearing impact melt clasts).A comprehensive study of petrology and mineralogy on several representative clasts was conducted by integrating Scanning Electron Microscopy(SEM),Tescan Integrated Mineral Analysis(TIMA),Electron Probe Microanalysis(EPMA)and Laser Ablation Inductively Coupled Plasma Mass Spectrometry(LA-ICP-MS)techniques.Evidence is sufficient that CE5C is a mixed mare-highland regolith breccia,with a high percentage of KREEPy material(20 vol.%),which has not been previously reported in other CE-5 samples.The mid-Ti impact glasses are characterized by high FeO(24.0 wt.%)and intermediate TiO_(2)(5.5 wt.%)contents,while the high-Al impact glasses have a chemical composition compatible with KREEP.Integrated with the regional geological context of the CE-5 landing site,we propose that CE5C is likely derived from a mixed region between the P58/Em4 mare unit and its contiguous eastern highlands.Despite the difficulty in assessing the representativeness of CE5C,the substantial presence of KREEPy material may provide valuable clues to the provenance of exotic ejecta,including the identification of unrecognized source craters situated in the eastern periphery of the sampling unit.