The distribution of water in the Moon's interior carries key implications for the origin of the Moon 1 , the crystallisation of the lunar magma ocean 2 , and the duration of lunar volcanism 2 . The Chang'E-5 (CE5) mission returned the youngest mare basalt samples, dated at ca. 2.0 billion years ago 3 , from the northwestern Procellarum KREEP Terrane (PKT), providing a probe into the spatio-temporal evolution of lunar water. Here we report the water abundance and hydrogen isotope composition of apatite and ilmenite-hosted melt inclusions from CE5 basalts, from which we derived a maximum water abundance of 370 ± 30 g.g -1 and a δD value (-330 ± 160‰) for their parent magma. During eruption, hydrogen degassing led to an increase in the D/H ratio of the residual melts up to δD values of 300-900‰. Accounting for low degrees of mantle partial melting followed by extensive magma fractional crystallisation 4 , we estimate a maximum mantle water abundance of 2-6 g.g -1 , which are too low for water contents alone to account for generating the Moon's youngest basalts. Such modest water abundances for the lunar mantle are at the lower end of those estimated from mare basalts that erupted from ca. 4.0-2.8 Ga 5, 6 , suggesting the mantle source of CE5 basalts dried up by ca. 2.0 Ga through previous melt extraction from the PKT mantle during prolonged volcanic activity.Water abundance in the lunar mantle places strict constraints on high-temperature processes, including the Moon-forming giant impact 1 , the ensuing crystallisation of the lunar magma ocean 7 , and the longevity of volcanism on the Moon 2 . Based upon the analyses carried out since the Apollo era, the Moon was long thought to be an anhydrous body. Advances in in situ analytical techniques over the past decade have allowed analysis of water abundances at micro-scale in various lunar samples, including in olivine-and pyroxene-hosted melt inclusions in mare basalts [8][9][10][11][12] , apatite in mare basalts and highlands samples [13][14][15][16][17][18][19][20] , pyroclastic glass beads 21, 22 , and

The 40Ar/39Ar dating method is among the most versatile of geochronometers, having the potential to date a broad variety of K-bearing materials spanning from the time of Earth’s formation into the historical realm. Measurements using modern noble-gas mass spectrometers are now producing 40Ar/39Ar dates with analytical uncertainties of ∼0.1%, thereby providing precise time constraints for a wide range of geologic and extraterrestrial processes. Analyses of increasingly smaller subsamples have revealed age dispersion in many materials, including some minerals used as neutron fluence monitors. Accordingly, interpretive strategies are evolving to address observed dispersion in dates from a single sample. Moreover, inferring a geologically meaningful “age” from a measured “date” or set of dates is dependent on the geological problem being addressed and the salient assumptions associated with each set of data. We highlight requirements for collateral information that will better constrain the interpretation of 40Ar/39Ar data sets, including those associated with single-crystal fusion analyses, incremental heating experiments, and in situ analyses of microsampled domains. To ensure the utility and viability of published results, we emphasize previous recommendations for reporting 40Ar/39Ar data and the related essential metadata, with the amendment that data conform to evolving standards of being findable, accessible, interoperable, and reusable (FAIR) by both humans and computers. Our examples provide guidance for the presentation and interpretation of 40Ar/39Ar dates to maximize their interdisciplinary usage, reproducibility, and longevity.

The bird fossil‐bearing deposits at the Jiecaigou section, correlative to the Dabeigou Formation, in Fengning, Hebei Province, northern China, is well known for yielding a fossil assemblage representing the earliest evolutionary stage of the Jehol Biota. The precise age of the fossil‐bearing deposits, however, is unknown. The 40Ar/39Ar age spectrum obtained on bulk K‐feldspars from the tuff layer about 2 m below the bird fossil‐bearing layer gave a plateau age of 129.0 ± 1.3 Ma (2σ, full external error) and an isochron age of 132.3 ± 4.5 Ma (2σ, full external error). Seventeen total‐fusion 40Ar/39Ar ages on K‐feldspars from the interbedded tuff about 6 m below the fossil‐bearing layer resulted in a weighted mean of 130.7 ± 1.4 Ma (2σ, full external error). These dates suggest an age of ∼131 Ma for the early Jehol Biota and combined with previous dating indicate that this biota lasted at least from 131 Ma to 120 Ma (Late Hauterivian to Aptian). These dates also represent the earliest absolute age for known enantiornithine birds in the world.

Remote sensing data revealed that the presence of water (OH/H 2 O) on the Moon is latitude-dependent and probably time-of-day variation, suggesting a solar wind (SW)-originated water with a high degassing loss rate on the lunar surface. However, it is unknown whether or not the SW-derived water in lunar soil grains can be preserved beneath the surface. We report ion microprobe analyses of hydrogen abundances, and deuterium/hydrogen ratios of the lunar soil grains returned by the Chang’e-5 mission from a higher latitude than previous missions. Most of the grain rims (topmost ~100 nm) show high abundances of hydrogen (1,116 to 2,516 ppm) with extremely low δD values (−908 to −992‰), implying nearly exclusively a SW origin. The hydrogen-content depth distribution in the grain rims is phase-dependent, either bell-shaped for glass or monotonic decrease for mineral grains. This reveals the dynamic equilibrium between implantation and outgassing of SW-hydrogen in soil grains on the lunar surface. Heating experiments on a subset of the grains further demonstrate that the SW-implanted hydrogen could be preserved after burial. By comparing with the Apollo data, both observations and simulations provide constraints on the governing role of temperature (latitude) on hydrogen implantation/migration in lunar soils. We predict an even higher abundance of hydrogen in the grain rims in the lunar polar regions (average ~9,500 ppm), which corresponds to an estimation of the bulk water content of ~560 ppm in the polar soils assuming the same grain size distribution as Apollo soils, consistent with the orbit remote sensing result.

The Hetian deposit, located south of the Tarim Basin in Xinjiang, China, is one of the world's largest dolomiterelated nephrite deposits. In the Alamas orebody of the deposit, nephrite occurs as veins or lenses along faults or fissures of the adjacent dolomitic marble. Chemical analyses using electronic microscope probe analysis and X-ray fluorescence spectroscope were carried out on nephrite and dolomitic marble samples collected from a cross section in Alamas to investigate zonal structure of the orebody. The nephrite in Alamas is predominately composed of tremolite with minor calcite, titanite and phlogopite, and that dolomitic marble is relatively pure with a FeO content less than 0.20 wt. %. Contents of color-inducing elements, such as Fe, Mn, and Cr, increase gradually as color changes from white through white-green and then to green, resulting in the formation of color-distinctive zones. Tremolite grain size increases as color changes from white through white-green to green. The trend may be consistent with temperature changes from dolomitic marble to granodiorite, which, in turn, suggests that both change in color from white to green and variations of grain size with increasing temperature resulting in formation of the nephrite zonal structure. Both nephrite zonal structure and minor minerals, such as calcite, titanite and phlogopite found in the contact, indicate that this dolomite-related nephrite orebody is of a metasomatic origin under assumed pressure of 100-200 MPa and temperature <550°C.

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A new natural zircon reference material SA01 is introduced for U‐Pb geochronology as well as O and Hf isotope geochemistry by microbeam techniques. The zircon megacryst is homogeneous with respect to U‐Pb, O and Hf isotopes based on a large number of measurements by laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) and secondary ion mass spectrometry (SIMS). Chemical abrasion isotope dilution thermal ionisation mass spectrometry (CA‐ID‐TIMS) U‐Pb isotopic analyses produced a mean 206Pb/238U age of 535.08 ± 0.32 Ma (2s, n = 10). Results of SIMS and LA‐ICP‐MS analyses on individual shards are consistent with the TIMS ages within uncertainty. The δ18O value determined by laser fluorination is 6.16 ± 0.26‰ (2s, n = 14), and the mean 176Hf/177Hf ratio determined by solution MC‐ICP‐MS is 0.282293 ± 0.000007 (2s, n = 30), which are in good agreement with the statistical mean of microbeam analyses. The megacryst is characterised by significant localised variations in Th/U ratio (0.328–4.269) and Li isotopic ratio (−5.5 to +7.9‰); the latter makes it unsuitable as a lithium isotope reference material.

Three standard minerals GA-1550 biotite, LP-6 biotite and Bern-4M muscovite used for K-Ar and 40 Ar-39 Ar dating have been investigated by the single grain Rb-Sr technique. Compared to the K-Ar and 40 Ar-39 Ar results previously reported, these mica standards nevertheless show complex characteristics in the Rb-Sr isotopic system. Analysis on eight individual grains of GA-1550 biotite gives a Rb-Sr isochron age of 98.7 ± 1.9 Ma, consistent with previous dating results of the K-Ar and stepwise heating and laser ablation 40 Ar-39 Ar methods. Although evidence of the laser ablation 40 Ar-39 Ar analyses in many previous studies demonstrates that LP-6 biotite is considerably inhomogeneous in the K-Ar isotopic system, Rb-Sr isotopic analyses on ten individual biotite grains show achievement of Sr isotopic equilibrium during crystallization. A Rb-Sr isochron age of 128.2 ± 2.2 Ma calculated from the analytical results is concordant with those previously reported K-Ar and 40 Ar-39 Ar ages obtained from c. 30 mg aliquots of biotite grains. Excellent age reproducibility on Bern-4M muscovite was previously achieved by K-Ar and 40 Ar-39 Ar dating by total fusion in c. 30 mg aliquots of muscovite grains, but single grain Rb-Sr analytical results in this study demonstrate considerable disequilibrium of Sr isotopic system during crystallization of muscovite. The discordance in the Rb-Sr and K-Ar isotopic systems of two standard minerals indicates complex factors that can influence isotopic disequilibrium of both isotopic systems.