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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]

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]

The unusually prolonged volcanism at the Chang'e‐5 (CE‐5) landing site remains a mystery. To constrain the geochemical features of the CE‐5 mantle source, we performed in situ sulfur isotope analysis on sulfides of the CE‐5 basalts. The modal abundance of sulfides is ∼0.1 wt%, dominated by troilite with trace cubanite, chalcopyrite and pentlandite, yielding a S‐abundance of ∼360 ± 180 ppm for the bulk CE‐5 basalts. Our analysis shows a decreasing trend of δ34S in the magma with crystallization and degassing, suggesting ∼40% degassing loss of S, and accordingly the maximum S‐abundance in CE‐5 primitive magma was calibrated to approximately 600 ± 300 ppm. Considering an extensive fractional crystallization following a low‐degree partial melting of the CE‐5 basalts, the estimated sulfur abundance in the mantle source is ∼1–10 ppm. This result suggests a strong depletion of volatiles in the CE‐5 mantle source, which may be caused by prolonged magmatic activity. Plain Language Summary: The Chang'e‐5 (CE‐5) basalts are the youngest lunar samples identified so far, extending our knowledge of the duration of lunar volcanism, but the main factors of prolonging the volcanic activity are still unclear. Sulfur, with four stable isotopes (32S, 33S, 34S, and 36S) and an active component in magmatic activity, can constrain the magmatic processes and geochemical features of the mantle source. Here, we report the S isotope compositions of troilite in the CE‐5 samples. The sulfides are mainly troilite, with trace Cu‐ and Ni‐sulfides. We counted the modal abundance of sulfides and then obtained the S abundance of the bulk CE‐5 basalts. Analysis indicates that S isotope fractionation exists in the CE‐5 troilite and is mainly due to magma degassing. According to the variation in S isotope compositions, we corrected for the degassing loss of S and obtain the S abundance of the CE‐5 magma before eruption. Furthermore, we estimated the S abundance of the CE‐5 basalt source based on the formation of the CE‐5 magma. This estimated value is significantly lower than the estimations for Apollo basalt sources, implying multiple extractions of sulfur‐bearing melts from the CE‐5 mantle source due to its prolonged magmatic activity. Key Points: The δ34S values of troilite in the Chang'e‐5 basalts range from −1.6‰ to +2.0‰The δ34S of troilite in the fine‐grained mesostasis are lighter than the inclusions in pyroxene, explained mainly by magma degassingIt is expected that the mantle source of the Chang'e‐5 basalts is depleted in sulfur, which is ∼1–10 ppm with a δ34S of ∼0.5‰ [ABSTRACT FROM AUTHOR]

The Chang'e‐5 (CE‐5) mission has successfully returned samples from a site that is much younger than the sites of all previous lunar sampling missions. Sample analysis results reported so far have revealed a more complex sampling area than previously thought, casting uncertainties over the interpretation of remote sensing spectral data and the U and Th abundance derived from the orbital data. Laboratory spectral measurement of the returned samples can serve as validation of remote sensing observations and thus help refine our understanding of the geological evolution of the landing region. In this study we report detailed micro mid‐infrared (MIR) spectral characteristics of individual soil grains of CE‐5 samples. The spectral analysis results show that the CE‐5 olivine grains have low Fo (molar Mg/[Mg + Fe] × 100) consistent with previous studies, indicating a Fe‐rich source region of the mantle or a highly evolved magma. These olivine grains show high level of crystallinity, implying low degree of space weathering. Most of the CE‐5 glasses analyzed are spectrally consistent with mare impact glasses, despite that a few of them may have a volcanic origin. These laboratory spectral analysis of CE‐5 samples in the MIR wavelengths at a micro scale, together with the derived MIR optical constants of the olivine, pyroxene, plagioclase, and glass grains, provide important input for the modeling and interpretation of thermal remote sensing data of the Moon. Plain Language Summary: The Chang'e‐5 (CE‐5) mission successfully landed in the north‐west of the Moon's nearside, and it returned samples that are quite different from previous returned samples. To study the compositions and possible origins of the samples, we performed a detailed micro mid‐infrared spectral analysis on individual mineral and glass grains. The ratio of Mg/(Mg + Fe), also called Fo, is often used to differentiate the magma source where the mineral formed. Our analysis results show that the CE‐5 olivine grains have low Fo values than previously returned olivine samples, indicating that its source region is rich in Fe. The CE‐5 olivine grains also have high level of crystallinity, implying they have not been exposed long enough to be deformed. We also found that most of the glass beads analyzed likely originated from impact within the maria region. Using remote sensing techniques like hyperspectral imaging, we can obtain composition information for a large‐scale region. Laboratory spectral analysis of returned samples can provide important ground‐truth for interpretations of remote sensing data. To build a link between returned sample and orbital spectral data, we derived the refractive index for typical mineral and glass samples, which will benefit the analysis of orbital spectral data. Key Points: Micro mid‐infrared spectral measurements were performed and optical constants were derived for typical Chang'e‐5 (CE‐5) soil grainsThe CE‐5 olivine grains have low Fo values, indicating a Fe‐rich source region or a highly evolved magmaMost of the CE‐5 glasses analyzed are likely attributed to mare impact group, despite a few others may have a volcanic origin [ABSTRACT FROM AUTHOR]

To further investigate copper (Cu) isotopic fractionation during seawater‐oceanic crust interactions, 13 subsamples across a basalt altering section and 12 bulk‐rock basalts from the southern Mariana and Yap trenches, western Pacific Ocean, were studied. We find that the δ65Cu values of the basalt section roughly increase from mid‐ocean ridge basalt‐like values (0.04% – 0.10%) in the core to higher values (up to 0.20%) near the core‐rim interface, and then lower values (down to −0.17%) at the rims. Isotopically light rims reflect the initial dissolution of Cu‐bearing sulfides releasing isotopically heavy Cu into ambient seawater, consistent with both lower Cu and sulfide contents in the altered rims. The elevated δ65Cu values reveal that sulfide dissolution induced a concentration‐driven diffusion from the core to rims, controlling the rim‐core‐rim Cu content and isotopic variations on centimeter scale. By contrast, the δ65Cu values of bulk‐rock basalts show a wide range (0.02% – 0.56%) with most samples enriched in heavy isotopes, and negatively correlate with Cu concentrations, indicating preferential adsorption of isotopically heavy Cu from seawater. We propose that chemical diffusion occurred prior to any adsorption processes, suggesting that a three‐stage process involving sulfide dissolution, chemical diffusion and adsorption controls Cu isotopic fractionation during seafloor basalt alteration. Plain Language Summary: Seawater‐oceanic crust interactions have been known to affect the 65Cu/63Cu isotopic ratios of both oceans and the oceanic crust, thus playing a key role on global copper (Cu) cycling. However, the behavior of Cu during seawater‐oceanic crust interactions remains poorly understood. We, for the first time, conduct a combined study on "in situ" δ65Cu values of 13 subsamples across a basalt altering section and whole‐rock δ65Cu values of 12 bulk basalts from the southern Mariana and Yap trenches. The rims in the basalt section have Cu isotopic compositions lighter than mid‐ocean ridge basalts, reflecting sulfide oxidation during seafloor alteration. The rim‐core‐rim Cu content and isotopic variation can be explained by a concentration‐driven diffusion from the core to rims after sulfide oxidation. Furthermore, the whole‐rock δ65Cu values with a wide range (0.02% – 0.56%) indicate that chemical diffusion may be followed by an absorption during seafloor alteration. The multistage Cu isotopic fractionation proposed here therefore is a step toward a more comprehensive picture of seawater‐oceanic crust interactions. Key Points: High‐precision copper (Cu) isotopic profile across a basalt altering section was reportedSystematic Cu and δ65Cu variations were produced by oxidative sulfide breakdown, diffusion and adsorptionMultistage Cu isotopic fractionation occurred during seafloor basaltic alteration [ABSTRACT FROM AUTHOR]

The voluminous Eocene postcollisional potassium‐rich magmatism in central Tibet is crucial in understanding the deep geodynamic process and related uplift history of the Tibetan Plateau. Here, we present an integrated study of whole‐rock Sr‐Nd‐Mg‐Li isotopes and zircon U‐Pb ages on two suites of lavas from Duocaima and Nariniya in the northern Qiangtang block. The Duocaima high‐K calc‐alkaline trachyandesites were formed at ~35 Ma and are enriched in light rare earth elements and large ion lithophile elements. They have slightly lower δ26Mg (−0.41‰ to −0.33‰) and δ7Li (+1.0‰ to +2.6‰) relative to the mantle. Together with their high 87Sr/86Sr(i) (0.7066–0.7067) and low ɛNd(t) (−1.96 to −1.61) values, they most likely originated from the lithospheric mantle previously metasomatized by melts from subducted carbonate‐bearing sediments. Model calculation suggests that ~7–11% sediments were added into the mantle via melting. By contrast, the contemporaneous Nariniya adakitic trachytes have higher δ26Mg (−0.13‰ to −0.02‰) and δ7Li (+3.3‰ to +5.4‰) values, as well as higher Pb/Ce and Ba/La ratios, which most likely resulted from the thickened lower crust that was metasomatized by fluids released from downgoing Songpan‐Ganzi oceanic slab. Our combined isotopic study suggests the existence of a remnant oceanic slab beneath central Tibetan Plateau during the late Eocene and implies that the initial uplift of central Tibet was before ~38 Ma. Key Points: Highly variable Mg and Li isotopes in potassium‐rich volcanic rocks from Qiangtang resulted from subducted slab inputsAn ancient remnant oceanic slab still existed beneath central Tibet during the late EoceneThe initial uplift of central Tibet was before ~38 Ma [ABSTRACT FROM AUTHOR]