Petrologic Insights Into the South Pole‐Aitken Basin From Raman Spectroscopy of Returned Chang'e‐6 Coarse Clasts

Abstract As the largest and oldest impact basin on the Moon, the South Pole‐Aitken (SPA) basin preserves critical information about the composition and evolution of the deep lunar crust and may even expose materials from the lunar mantle. China's Chang'e‐6 mission returned the first farside samples from the southern mare unit of the Apollo basin within the SPA basin, where the regolith records a complex geological history and diverse non‐mare lithologies. In this study, Raman spectroscopy was applied to 50 coarse‐grained clasts (average diameter of ∼950 μm) from the Chang'e‐6 samples to investigate their mineral composition and reveal the lithological diversity of the farside crust within the SPA basin. Based on modal mineralogy, these clasts are classified into breccias ( n = 34), basalts ( n = 8), and non‐mare lithologies ( n = 8). The non‐mare clasts are dominated by norite ( n = 5), anorthosite ( n = 2), and troctolite ( n = 1), exhibiting Mg# values (molar [Mg/(Mg + Fe)] × 100) of olivine and/or pyroxene ranging from 53 to 73. Notably, noritic clasts provide direct sample‐based evidence that the Mg‐rich pyroxene annulus of the SPA basin is predominantly composed of ferroan norite, with an average Mg# of ∼64 and model abundances of ∼61 vol% plagioclase and ∼29 vol% orthopyroxene. These results provide new insights into the crustal composition and evolution of the lunar farside within the SPA basin. This study demonstrates the capability of Raman‐based lithologic classification and highlights its potential for future in situ mineralogical investigations in forthcoming lunar exploration by Chang'e‐7 Lunar Raman Spectrometer.