^1,2Roberto Borriello,³Fahui Xiong,⁴Chi Ma,¹Sofia Lorenzon,¹Enrico Mugnaioli,⁵Jingsui Yang,⁶Xiangzhen Xu,⁷Edward S. Grew
American Mineralogist 110, 630-642 Link to Article [https://doi.org/10.2138/am-2024-9362]
¹Department of Earth Sciences, University of Pisa, Via S. Maria 53, 56126 Pisa, Italy
²Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of Venice, Via Torino 155, 30172 Mestre (VE), Italy
³Center for Advanced Research on the Mantle (CARMA), Key Laboratory of Deep-Earth Dynamics of Ministry of Land and Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
⁴Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, U.S.A.
⁵School of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China
⁶Center for Advanced Research on the Mantle (CARMA), Key Laboratory of Deep-Earth Dynamics of Ministry of Land and Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
⁷School of Earth and Climate Sciences, University of Maine, Orono, Maine 04469, U.S.A.
Copyright: The Mineralogical Society of America

^1,2Ziliang Jin,^3,4,5Tong Hou,^1,2Meng-Hua Zhu,^6,7Yishen Zhang,⁶Olivier Namur
American Mineralogist 110, 560–569 Link to Article [https://doi.org/10.2138/am-2024-9448]
¹State Key Laboratory of Lunar and Planetary Science, Macau University of Science and Technology, Taipa, 999078, Macao, China
²CNSA Macau Center for Space Exploration and Science, Taipa 999078, Macau, China
³State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, 100083 Beijing, China
⁴Key Laboratory of Intraplate Volcanoes and Earthquakes (China University of Geosciences, Beijing), Ministry of Education, Beijing 100083, China
⁵Institute of Mineralogy, Leibniz Universität Hannover, Callinstr. 3, 30167, Hannover, Germany
⁶Department of Earth and Environmental Sciences, KU Leuven, 3000, Leuven, Belgium
⁷Department of Earth, Environmental and Planetary Sciences, Rice University, 6100 Main Street, MS 126, Houston, Texas 77005, U.S.A.
Copyright: The Mineralogical Society of America

This study investigates silicate liquid immiscibility (SLI) microstructures in the Chang’E-5 (CE-5) lunar ferrobasalt sample, the youngest recovered mare basalt (ca. ∼2.0 Ga). Employing advanced high-resolution imaging techniques and chemical analysis, we examined a subophitic fragment, revealing two distinct types of microstructures indicative of multi-stage SLI events. The first type is observed in the mesostasis pockets and exhibits both “sieve” and “maze” textures, where the Si-K-rich glassy phases are interconnected with Fe-rich minerals, e.g., fayalite. This type of microstructure, similar to previous observations in Apollo and Luna samples, is the product of a stable SLI event. The second type is characterized by K-free but high-Si melt inclusions occurring as emulsions in the rims of plagioclase. The entrapment of these emulsions followed a metastable SLI event, with the Fe-rich liquids serving as precursors to subsequent stable SLI processes. Additionally, the Fe-rich droplets within the emulsions underwent coarsening via Ostwald ripening, a phenomenon in which smaller particles in solution dissolve and deposit on larger particles. Our simulation of this coarsening process suggests a duration of at least 15–32 days for the SLI processes, alongside a slow cooling rate (<0.3 °C/h) of the late-stage CE-5 lava. We propose that metastable SLI may have influenced the effusive signature of the CE-5 lava flow during its late-stage evolution. The metastable SLI process can potentially lead to the formation of various phases during the late-stage evolution of lunar ferrobasaltic magmas, thereby contributing to the diversity of lunar rock types.