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The distribution of water in the Moon’s interior carries implications for the origin of the Moon 1 , the crystallization of the lunar magma ocean 2 and the duration of lunar volcanism 2 . The Chang’e-5 mission returned some of the youngest mare basalt samples reported so far, dated at 2.0 billion years ago (Ga) 3 , from the northwestern Procellarum KREEP Terrane, providing a probe into the spatiotemporal evolution of lunar water. Here we report the water abundances and hydrogen isotope compositions of apatite and ilmenite-hosted melt inclusions from the Chang’e-5 basalts. We derive a maximum water abundance of 283 ± 22 μg g −1 and a deuterium/hydrogen ratio of (1.06 ± 0.25) × 10 – 4 for the parent magma. Accounting for low-degree partial melting of the depleted mantle followed by extensive magma fractional crystallization 4 , we estimate a maximum mantle water abundance of 1–5 μg g −1 , suggesting that the Moon’s youngest volcanism was not driven by abundant water in its mantle source. Such a modest water content for the Chang’e-5 basalt mantle source region is at the low end of the range estimated from mare basalts that erupted from around 4.0 Ga to 2.8 Ga (refs. 5 , 6 ), suggesting that the mantle source of the Chang’e-5 basalts had become dehydrated by 2.0 Ga through previous melt extraction from the Procellarum KREEP Terrane mantle during prolonged volcanic activity. Water abundance and hydrogen isotope compositions of two-billion-year-old basalt samples returned from the Moon by the Chang’e-5 mission suggest that the samples came from a relatively dry mantle source.

Water has been detected on the lunar surface and attributed to delivery by impacts and the solar wind to a dry early Moon. Spectroscopic detections of water in lunar anorthosites from the Apollo collection suggest that a significant amount of water is indigenous to the Moon. The Moon was thought to be anhydrous since the Apollo era 1 , but this view has been challenged by detections of water on the lunar surface 2 , 3 , 4 and in volcanic rocks 5 , 6 , 7 , 8 , 9 and regolith 10 . Part of this water is thought to have been brought through solar-wind implantation 2 , 3 , 4 , 7 , 10 and meteorite impacts 2 , 3 , 7 , 11 , long after the primary lunar crust formed from the cooling magma ocean 12 , 13 . Here we show that this primary crust of the Moon contains significant amounts of water. We analysed plagioclase grains in lunar anorthosites thought to sample the primary crust, obtained in the Apollo missions, using Fourier-transform infrared spectroscopy, and detected approximately 6 ppm water. We also detected up to 2.7 ppm water in plagioclase grains in troctolites also from the lunar highland upper crust. From these measurements, we estimate that the initial water content of the lunar magma ocean was approximately 320 ppm; water accumulating in the final residuum of the lunar magma ocean could have reached 1.4 wt%, an amount sufficient to explain water contents measured in lunar volcanic rocks. The presence of water in the primary crust implies a more prolonged crystallization of the lunar magma ocean than a dry moon scenario and suggests that water may have played a key role in the genesis of lunar basalts.

The past two decades of lunar exploration have seen the detection of substantial quantities of water on the Moon’s surface. It has been proposed that a hydrated layer exists at depth in lunar soils, buffering a water cycle on the Moon globally. However, a reservoir has yet to be identified for this hydrated layer. Here we report the abundance, hydrogen isotope composition and core-to-rim variations of water measured in impact glass beads extracted from lunar soils returned by the Chang’e-5 mission. The impact glass beads preserve hydration signatures and display water abundance profiles consistent with the inward diffusion of solar wind-derived water. Diffusion modelling estimates diffusion timescales of less than 15 years at a temperature of 360 K. Such short diffusion timescales suggest an efficient water recharge mechanism that could sustain the lunar surface water cycle. We estimate that the amount of water hosted by impact glass beads in lunar soils may reach up to 2.7 × 1014 kg. Our direct measurements of this surface reservoir of lunar water show that impact glass beads can store substantial quantities of solar wind-derived water on the Moon and suggest that impact glass may be water reservoirs on other airless bodies.Analysis of lunar soils sampled by the Chang’e-5 mission suggests that impact glass beads may host a substantial inventory of solar wind-derived water on the Moon’s surface.

The history of mare volcanism critically informs the thermal evolution of the Moon. However, young volcanic eruptions are poorly constrained by remote observations and limited samples, hindering an understanding of mare eruption flux over time. The Chang’e-5 mission returned the youngest lunar basalts thus far, offering a window into the Moon’s late-stage evolution. Here, we investigate the mineralogy and geochemistry of 42 olivine and pyroxene crystals from the Chang’e-5 basalts. We find that almost all of them are normally zoned, suggesting limited magma recharge or shallow-level assimilation. Most olivine grains record a short timescale of cooling. Thermal modeling used to estimate the thickness and volume of the volcanism sampled by Chang’e-5 reveals enhanced magmatic flux ~2 billion years ago, suggesting that while overall lunar volcanic activity may decrease over time, episodic eruptions at the final stage could exhibit above average eruptive fluxes, thus revising models of lunar thermal evolution. This work estimates the eruption volume of the young Chang’e-5 lunar samples using diffusion chronology and thermodynamic simulations, and finds that there was an increase in volcanic eruption flux about 2.0 billion years ago.

We employed MC‐ICP‐MS to measure the mass‐dependent Ca isotope compositions of Vesta‐related meteorites. Eucrites and diogenites show distinct Ca isotope compositions, which is caused by crystallization of isotopically heavy orthopyroxene. The Ca isotope data support a model where the two lithologies are linked, where the diogenites, mainly composed of orthopyroxene crystallized from an eucritic melt. As normal eucrites are the main Ca reservoir on Vesta, their δ44/40Ca values (per mil 44Ca/40Ca ratios relative to NIST 915a) best represents that of bulk silicate Vesta (0.83 ± 0.04‰). This value is different from those of bulk Earth (0.94 ± 0.05‰) and Mars (1.04 ± 0.07‰), suggesting that there exists notable Ca isotope heterogeneity between inner solar system bodies. The δ44/40Ca difference between chondrules and these planets does not support the pebble accretion model as the main mechanism for planetary growth. Plain Language Summary Calcium is a major, refractory element in solar system, and its mass‐dependent isotope fractionation effect is a robust proxy for probing planetary magmatic evolution and tracing the genetic relationships between solar system materials. We report high‐precision Ca isotope data for the howardite‐eucrite‐diogenite and mesosiderite meteorites, which potentially derive from the asteroid 4 Vesta, to better understand the origin and differentiation of Vesta. Eucrites and diogenites have different mass‐dependent Ca isotope compositions, which is caused by orthopyroxene crystallization from a magma ocean. We have modeled the Ca isotope evolution of this magma ocean and find that eucrites and diogenites can have formed from this melt. Eucrites show similar Ca stable isotope compositions to howardites and mesosiderites, consistent with a mixing model of eucrites and diogenites for howardites and the silicate portion of mesosiderites originating from Vesta. The Ca‐rich eucrites can best represent the Ca isotope composition of bulk Vesta. It shows Earth, Mars, and Vesta do not share a common Ca isotope composition, suggesting their potentially different precursor material. All these planets and asteroids possess different Ca isotope composition from the chondrules formed in the inner solar system, which does not support a chondrule‐rich model for accretion of terrestrial planets. Key Points Eucrites possess isotopically light Ca than diogenites; the Ca isotope modeling shows they are co‐genetic Earth, Mars, and Vesta do not share a common Ca isotope reservoir, reflecting isotopic heterogeneities in the inner solar system The Ca stable isotopes of the planets/asteroids do not overlap those of chondrules, which does not support a chondrule‐rich model for planet accretion

The redox state of a planetary mantle affects its thermal evolution. The redox evolution of lunar mantle, however, remains unclear due to limited oxygen fugacity ( f O 2 ) constraints from young lunar samples. Here, we report vanadium (V) oxybarometers on olivine and spinel conducted on 27 Chang’e-5 basalt fragments from 2.0 billion years ago. These fragments yield an average f O 2 of ΔIW -0.84 ± 0.65 (2σ), which closely aligns with the Apollo samples from 3.6–3.0 billion years ago. This temporal uniformity indicates the lunar mantle remained reduced. This observation reveals that the processes responsible for oxidizing mantles of Earth and Mars either did not occur or had negligible oxidizing effects on the Moon. The long-term reduced mantle may lead to a distinctive volatile degassing pathway for the Moon. It could also make the lunar mantle more difficult to melt, preventing internal heat dissipation and consequently resulting in a slow cooling rate. The lunar mantle may have remained reduced, according to the oxygen fugacity of 2.0 Ga Chang’e-5 basalt that is similar to 3.6 − 3.0 Ga Apollo basalts and pyroclastic glasses.

Water is the one of most precious resources for planetary utilisation. Lunar nearside impact glass beads (IGBs) have been demonstrated to contain abundant solar wind-derived water (SW-H 2 O); however, little is known about its farside counterpart. Here, we report the water abundances and hydrogen isotope compositions and their distribution in farside IGBs collected by the Chang’e-6 mission to investigate the role of IGBs in the lunar surface water cycle. Farside IGBs are found to have water abundances of ~10–1,070 μg.g −1 with hydrogen isotopes (δD) ranging from –988‰ to >2000‰ and display typical SW-H 2 O hydration profiles. The SW-H 2 O hydration depths in farside IGBs are strikingly shallower than in nearside IGBs. Moreover, the hydration profiles are only found in mare IGBs, with none observed in non-mare IGBs, indicating that SW-H 2 O hydration in IGBs is likely composition dependent. These findings indicate that SW-H 2 O storage of IGBs exhibits a dichotomy distribution in lunar soils. The storage of solar wind-derived water of impact glass beads exhibits a dichotomy distribution in the lunar soils.

Trace amount of water associated with the lattice defects of nominally anhydrous minerals （NAMs） can be measured using Fourier transform infrared spectroscopy （FTIR） and secondary ion mass spectrometry （SIMS）. Lots of data on water in NAMs from different lithologies, especially mantle peridotite xenoliths, have been published. The water distribution in olivine from peridotite xenoliths often displays a diffusion profile with high water concentration in the core and low at the rim, which indicates water loss via diffusion during the ascent of host magma. On the other hand, water is homogeneously distributed in pyroxene and its concentration is typically interpreted to represent a mantle value. The water concentration of magma in equilibrium with NAM can be estimated using specific partition coefficient, from which the water content of parental magma and the mantle source can be inferred. The accuracy of this method, however, depends on the selection of appropriate partition coefficient for the system. Using hydrogen isotope compositions and H2O/Ce ratios of mantle NAMs, water source regions can be traced and water heterogeneity can be mapped in the upper mantle. Water plays an important role in the stability of cratonic mantle. The water contents and vertical distribution patterns can be significantly different among different cratonic manties, which may result from different geologic activities. However, the mantle-plume interaction may not necessarily result in significant change of water content in cratonic mantle. The estimation of the water content in the upper mantle is still largely based on geochemical models due to the limitations of data on water in mantle NAMs.

The paradigm of lunar crust formation has been widely applied to other terrestrial bodies, but the nature of early crust building on the Moon remains enigmatic. Here we report non-Apollo-like highland clasts from the Chang’e-5 mission and find high-alumina melts enclosed in a noritic anorthosite. Geochemistry and phase equilibria modeling suggest that the melt is compositionally parental to lunar magnesian-suite rocks, and was sourced from a plagioclase-bearing, orthopyroxene-dominated upper mantle ( ~ 4.5 kbar and 1225°C). It was formed as a direct consequence of upper mantle melting at the onset of gravitational instability. We propose a continuous early crust formation on the Moon, started from multiple anorthositic cumulate flotations, to upper mantle melting caused by small-scale, in-situ overturn, and eventually ended up by decompression melting of lower mantle cumulates following large-scale, global overturn.The first magma on the Moon formed by decompression melting of orthopyroxene-dominated mantle rocks facilitated by density-driven mantle overturn, according to petrographic modelling and observations of lunar highland samples from the Chang’e-5 mission

Hydrogen concentrations in minerals of peridotite xenoliths in alkali basaltic rocks from Quaternary volcanoes in northwest Spitsbergen were measured using polarized Fourier transform infrared spectroscopy (FTIR) to trace the effects of geologic processes on hydrogen distribution in the continental lithospheric mantle. The mineral grains show hydrogen profiles with lower concentrations at rims suggesting diffusive hydrogen loss during the entrapment and transport of the xenoliths in magma. However, hydrogen concentrations in the centers of the grains are uniform and appear to represent hydrogen abundances in the Spitsbergen upper mantle. The olivine, orthopyroxene, and clinopyroxene contain 1–10, 130–290, and 350–560 ppm H O, respectively. Hydrogen abundances away from metasomatic melt conduits recorded by Type 1 xenoliths are correlated with the concentrations of incompatible trace elements, indicating that hydrogen distribution is related to mantle metasomatism. By contrast, hydrogen near the melt conduits, recorded by Type 2 xenoliths, shows no regular correlations with incompatible trace elements (except Nb in clinopyroxene) and may be affected by fractional crystallization of amphibole in the conduits. Hydrogen contents decrease away from the melt conduits and are controlled by the interaction between the depleted host mantle and percolating metasomatic melts. Therefore, the metasomatic melt could have variably hydrated the Spitsbergen upper mantle via different processes. The H O/Ce ratios of the melt in equilibrium with clinopyroxene near the metasomatic melt conduits range from 93 to 218, i.e., within the oceanic island basalt (OIB) range. This is consistent with that the metasomatic melt could have been derived from OIB-type sources evidenced by the Sr-Nd isotope compositions of the xenoliths.