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Knowledge regarding the abundance and distribution of solar wind (SW)‐sourced water (OH/H2O) on the Moon in the shallow subsurface remains limited. Here, we report the NanoSIMS measurements of H abundances and D/H ratios on soil grains from three deepest sections of the Chang'E‐5 drill core sampled at depths of 0.45–0.8 m. High water contents of 0.13–1.3 wt.% are present on approximately half of the grain surfaces (topmost ∼100 nm), comparable to the values of Chang'E‐5 scooped soils. The extremely low δD values (as low as −995‰) and negative correlations between δD and water contents indicate that SW implantation is an important source of water beneath the lunar surface. The results are indicative of homogeneous distribution of SW‐derived water in the vertical direction, providing compelling evidence for the well‐mixed nature of the lunar regolith. Moreover, the findings demonstrate that the shallow subsurface regolith of the Moon contains a considerable amount of water. Plain Language Summary: Recently, China's Chang'E‐5 mission targeted a higher latitude on the Moon than previous Apollo and Luna missions, and brought back scooped and drilled samples to the Earth. These new soil samples provide an opportunity to investigate the distribution, abundance, and origin(s) of water in Moon's middle latitude. Here, we focus on using the NanoSIMS technique to analyze water content on soil near‐surface regions to understand whether the solar wind (SW)‐derived water could be preserved after burial at depth. Our results show that more than half of the core soils have high water contents on the rims of grains, similar to those of the Chang'E‐5 scooped soils. This finding suggests that the SW remains an important source of water in the Moon's subsurface. Our work provides direct evidence that the lunar regolith below the surface contains considerable water from SW implantation. This type of water could be a promising water resource in future exploration. Key Points: More than half of the soils from the single drill core have high water contents and low D/H ratios below the surfaceThe solar wind (SW)‐derived water could be preserved for hundreds of millions of years if buried at depthLunar regolith from the drill core contains considerable water from SW implantation, which is much more accessible [ABSTRACT FROM AUTHOR]

The Chinese spacecraft Chang'e-5 (CE-5) landed on the northern Ocean Procellarum and returned 1,731 grams of regolith. The CE-5 regolith is composed mostly of fragments of basalt, impact glass, agglutinates, and mineral fragments. The basalts could be classified as of a low-Ti and highly fractionated type based on their TiO2 content of ∼5.3 wt% and Mg# of ∼28. Independent of petrographic texture, the CE-5 basalts have a uniform eruption age of 2,030 ± 4 Ma, demonstrating that the Moon remained volcanically active until at least ∼2.0 Ga. Although the CE-5 landing site lies within the so-called Procellarum KREEP [potassium (K), rare earth elements (REE), and phosphorus (P)] Terrane, neither the CE-5 basalts nor the mantle source regions of those basalts were enriched in KREEP components, such as incompatible elements, water, sulfur, or chlorine. Therefore, it would be a new and stimulating task in the future to look for the triggering mechanism of the young volcanism on the Moon. The CE-5 spacecraft returned 1,731 grams of lunar regolith in December 2020. It was the first new lunar sample since the last collection in August 1976. CE-5 regolith is basaltic in chemical composition, with only ∼1% highland materials of anorthosite, Mg suite, alkali suite, and KREEP. The CE-5 basalt is low Ti and highly differentiated. It was extruded at ∼2.0 Ga, being the youngest lunar basalt identified so far from the Moon. The triggering mechanism of the ∼2.0 Ga lunar volcanism is not clearly understood because its mantle source was dry and contained low abundances of KREEP elements. [ABSTRACT FROM AUTHOR]

Glasses cooled from impact melt and vapor are a common component in lunar regolith, carrying important information about protolith composition, regolith formation, and impact flux on the Moon. Interpretations, however, are frequently challenged due to widespread ambiguity in determining their provenances. Regolith samples returned by China's Chang'E‐5 mission provide a unique opportunity to study the microscopic mechanism of regolith reworking on the Moon, because as evidenced by the coherent radioisotope ages and petrographic characteristics of basaltic clasts in the regolith, the Chang'E‐5 regolith was mainly evolved from local mare materials, containing minor exotic components. Here, we report 153 glass particles larger than 20 μm in diameters that were screened from 500 mg of Chang'E‐5 regolith. Most glass particles have rotational shapes and contain structural and/or compositional heterogeneities in interiors, and geochemical analyses reveal a dominant origin as impact melt of local mare materials. Surfaces of the impact glasses are observed to have abundant protruded and dented microstructures, which are classified as different groups based on their morphology and geochemistry. Similar microstructures were observed on impact spherules collected by the Apollo and Luna missions, but those on the Chang'E‐5 impact glasses were formed without substantial involvement of exotic ejecta. Microstructures such as silicate melt pancakes that frequently exhibit flow spikes at margins, nano‐phase iron‐rich mounds that are arranged with semi‐equidistant spaces in curves and patches, spatially clustered microcraters that are indicative of secondary impacts, and blunt linear scratches with terminal particles all suggest that regolith reworking mainly occurred among local materials at low speeds. Plain Language Summary: Regolith particles on the Moon exhibit an abundance of small‐scale surface texture or microstructures that were formed during regolith reworking. Lunar impact glasses are mainly melted from surface regolith, and microstructures on their surfaces record the history of subsequent regolith reworking. The possible contribution of exotic ejecta in regolith gardening is an interesting topic in lunar science. However, resolving this issue has been a persistent difficulty by both remote observations and sample analyses. China's Chang'E‐5 mission returned regolith samples from one of the youngest mare units on the Moon, and earlier sample analyses revealed little exotic components. In 500 mg of Chang'E‐5 regolith, we handpicked 153 glass particles that are larger than 20 μm. Most of the particles are heterogeneous impact glasses that contain voids and unmelted fragments, and geochemical analyses showed that the remaining structurally homogeneous particles were also impact glasses formed from local regolith. Based on high‐resolution microscopic imaging and elemental mapping, we recognized and classified the abundant protruded and dented microstructures on the glass particles. Morphology and crosscutting relationship of the microstructures suggest that they were mostly formed during regolith reworking by low‐speed events of local materials that had various thermophysical states (vapor, melt, and solid). Key Points: 153 glass particles larger than 20 μm in diameters are separated from 500 mg of Chang'E‐5 regolithCrosscutting relationships among surface microstructures reveal intricate regolith reworking processesProtruded and dented microstructures on surfaces of Chang'E‐5 glass particles were formed with velocities lower than primary impacts [ABSTRACT FROM AUTHOR]

Lunar impact glasses can provide important information on the bulk compositions of their sources and the impact history of the Moon. Here, we report the chemical composition of fifty-four clean glass spherules containing neither relict clasts nor crystals from the Chang'e-5 (CE5) regolith. They can be subdivided into three compositional groups: (1) mid-Ti basaltic (TiO 2 = 4.1 ∼ 6.5 wt%), (2) low-Ti basaltic (TiO 2 = 1.3 ∼ 3.9 wt%), and (3) high-Al (Al 2 O 3 > 15 wt%). Fifty-one glasses (∼94 %) are mid-Ti basaltic, which form a loose compositional cluster for most major and trace elements. These glasses exhibit considerable variations in SiO 2 (35.3 ∼ 45.3 wt%). Their TiO 2 , Al 2 O 3 , MgO and CaO show negative correlations with SiO 2 , while the Na 2 O, K 2 O and P 2 O 5 positively correlate with SiO 2 , also yielding a positive correlation between the CIPW normative plagioclase and olivine. These variations likely result from differential vaporization of SiO 2 , strongly suggesting an impact origin of these glasses. Their major and trace element compositions are averagely similar to the bulk-rock, in turn indicating that they were formed from the local regolith. The remaining three glasses, including two low-Ti basaltic and one high-Al variety, exhibit distinct major and trace elements from the regolith, indicating an exotic source. In addition, the mid-Ti basaltic glasses provide another approach for estimating the average composition of the CE5 basalt other than directly measuring the small basalt fragments assuming that the exotic materials in the CE5 regolith were limited. This estimation reveals critical trace element characteristics of the CE5 basalt, e.g., it has higher La/Yb (3.71), Sm/Yb (1.76), Sr/Yb (31.6), and (Eu/Eu*) N (0.45) than KREEP, indicating that CE5 basalt must derive from a non-KREEP source. Chemical modeling indicates that the contribution of KREEP-rich materials in the mantle source should be less than 0.3 %. The trace element characteristics of the CE5 basalt can be reproduced by extensive (80 %) fractional crystallization after low-degree (2 %) melting. We propose that this fractional crystallization process might occur at depth, implying vast igneous underplating (7,250 ∼ 11,750 km3) beneath the CE5 landing area. This study also suggests that the high Th concentration (5.43 ppm) is an inherent property of the CE5 basalt resulting from extensive fractional crystallization. Thus, high Th detected by remote sensing may not be associated directly with a KREEP component but rather with highly fractionated basalts. [ABSTRACT FROM AUTHOR]