Copernican‐Aged (<200 Ma) Impact Ejecta at the Chang'e‐5 Landing Site: Statistical Evidence From Crater Morphology, Morphometry, and Degradation Models

Abstract

Chang'e-5 (CE-5) is China's first lunar sample-return mission. It landed in northern Oceanus Procellarum on December 1, 2020, at 43. 06°N, 51.92°W (Wang et al., 2021). 1,731 g of lunar regolith was collected and are currently under laboratory investigations.The CE-5 site (Statio Tianchuan, IAU-name) is located within Eratosthenian-aged intermediate-Ti mare basalts (labeled as Em4/P58 by Qian, Xiao, Wang, et al., 2021), with an average thickness of ∼51 m, a total volume between 1,450 and 2,350 km 3 (Qian, Xiao, Head, , and a ∼7 m thick regolith superposed (Yue et al., 2019). The CE-5 sample-return strategy included a 2 m-drill (∼1 m was recovered) and a surface sampling device (Deng et al., 2021). The returned samples are thus likely to contain materials from different sources, including local basalts mixed by vertical and lateral transportation with exotic materials (Huang et al., 2017;Liu, Michael, Zuschneid, et al., 2021). The local mare materials might be erupted from Rima Sharp and will help to better understand the nature of late-stage volcanism, deep mantle properties, and lunar chronologies; the distal materials would

New Occurrence of Seifertite and Stishovite in Chang’E‐5 Regolith

“…The exotic ejecta in CE‐5 regolith are mainly from five proximal and four distant craters (Qian, Xiao, Head, et al., 2021; Qian, Xiao, Wang, et al., 2021). The five proximal craters (<1 km) are too small to fit with our calculations.…”

“…And also, the average thickness of lunar regolith layer for maria and highlands areas are only ∼5 and 12 m, respectively (Shkuratov & Bondarenko, 2001), whereas the excavation depth of large impact craters can be hundreds of meters to several kilometers (compiled data from Qian, Xiao, Head, et al. (2021) and Qian, Xiao, Wang, et al. (2021)), thus the low‐porosity bedrock can be excavated, which could be the host for seifertite and stishovite.…”

“…Repetitive impacts on the Moon lead to mixing of genuine local materials and exotic materials delivered by distal cratering events, controlling the dynamic evolution of lunar regolith (Hörz, 1977). Quantifying the contribution of exotic materials conventionally relies on remote sensing observations (Qian, Xiao, Head, et al., 2021; Qian, Xiao, Wang, et al., 2021), while investigations on returned lunar samples can provide more specific information on these exotic materials. Chang’E‐5 (“CE‐5” hereafter) mission has successfully returned 1,731 g lunar regolith samples (Li et al., 2021), which predominantly consist of young mare basalts from a dry and non‐KREEP mantle source (Che et al., 2021; Hu et al., 2021; Li et al., 2021; Tian et al., 2021) and a small amount of impact breccias.…”

In Situ Investigation Of The Valence States Of Iron-Bearing Phases In Chang’E-5 Lunar Soil Using FIB, AES, And TEM-EELS Techniques

“…The short space exposure history of CE-5 lunar soil indicated that it endured relatively modest space weathering alterations. 19 This provides the necessary conditions for preserving information regarding the initial evolutionary stage of lunar soil.…”

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

“…The CE-5 lunar samples can be regarded as the weathering and mixing products of local rocks (∼91 wt%, , with minimal ejecta materials from Harpalus, Copernicus, and Aristarchus craters (Qian, Xiao, Head, Wöhler, et al, 2021). Previous research (Che et al, 2021;He et al, 2022;Jiang et al, 2021;C.…”