Petrogenesis of Lunar Farside Highland Lithologies: Implications for Lunar Crust Formation

Abstract The lunar soil samples collected by the Chang’e-6 (CE-6) mission provide a unique opportunity to study the composition and formation of the lunar crust on the farside of the Moon. This study examines the petrogenesis of anorthosites and noritic anorthosites from the lunar farside using samples collected by the CE-6 mission. The analysis reveals that the ferroan anorthosite (FAN) clasts display plagioclase An# and mafic mineral Mg# within the range of Apollo FANs, highlighting the compositional similarity between the lunar nearside and farside. The identification of FANs on the farside underscores the global nature of these lithologies, indicating that the early lunar crust formation processes were not confined to the nearside but were widespread across the Moon. The noritic anorthosite clast shows characteristics consistent with KREEP-free/poor Mg-suite rocks. This finding supports the idea that both the nearside and farside experienced similar magmatic processes, challenging the simplistic hemispheric dichotomy models. The study emphasizes significant lithological variations at local scale and the need for further sample-return missions to elucidate the compositional diversity and formation history of the lunar crust.