A Raman Spectroscopic and Microimage Analysis Perspective of the Chang'e‐5 Lunar Samples

Abstract

Abstract The Chang'e‐5 (CE‐5) materials represent the youngest returned lunar samples. We performed a detailed Raman spectroscopic survey (1259‐point Raman modal analysis) to evaluate the mineralogical characteristics of CE‐5 soils, constraining the source materials and shock effects of these unique samples. The mineral chemistry (e.g., Mg# 3‐60 for mafic minerals) and modal abundance (first distinguishing basaltic and feldspathic glasses) of CE‐5 mare soils are different from those of Apollo high‐ and low‐Ti basalts, possibly representing an intermediate‐Ti mare basalt. The occurrence of minor Mg‐rich materials (Mg# > 70) provides evidence of contamination from ∼5% to 7% exogenous materials, possibly related to Mg‐suite rocks. The microimage analyses suggest that the CE‐5 soils are fine‐grained, mature, and unimodal particle‐size distribution, highlighting that micrometeorite reworking dominates the CE‐5 regolith evolution with minor mixing from nonmare materials. The pressure‐sensitive minerals (quartz and maskelynite) indicate that 17–25.8 GPa shock pressures might be the higher limit in a relatively young lunar terrain.