In this chapter, we review the contribution of space missions to the determination of the elemental and isotopic composition of Earth, Moon and the terrestrial planets, with special emphasis on ...currently planned and future missions. We show how these missions are going to significantly contribute to, or sometimes revolutionise, our understanding of planetary evolution, from formation to the possible emergence of life. We start with the Earth, which is a unique habitable body with actual life, and that is strongly related to its atmosphere. The new wave of missions to the Moon is then reviewed, which are going to study its formation history, the structure and dynamics of its tenuous exosphere and the interaction of the Moon’s surface and exosphere with the different sources of plasma and radiation of its environment, including the solar wind and the escaping Earth’s upper atmosphere. Missions to study the noble gas atmospheres of the terrestrial planets, Venus and Mars, are then examined. These missions are expected to trace the evolutionary paths of these two noble gas atmospheres, with a special emphasis on understanding the effect of atmospheric escape on the fate of water. Future missions to these planets will be key to help us establishing a comparative view of the evolution of climates and habitability at Earth, Venus and Mars, one of the most important and challenging open questions of planetary science. Finally, as the detection and characterisation of exoplanets is currently revolutionising the scope of planetary science, we review the missions aiming to characterise the internal structure and the atmospheres of these exoplanets.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In situ U-Pb radiometric dating of zircons is regarded as one of the most widely used and reliable methods to acquire geochronologic ages. However, it has been recently reported that radiogenic Pb ...(Pb*) mobilization within zircon may, in some cases, cause inaccurate age determinations with no geological significance. Such Pb* mobilization can be caused by deformation, α-coil damage, fluid-assisted annealing, and recrystallization. In this study, we report an investigation of Pb* mobilization in shock metamorphosed lunar zircons. NanoSIMS (nanoscale secondary ion mass spectrometry) and IMS 1280HR ion microprobe dating, EBSD (electron backscatter diffraction) and CL (cathodoluminescence) mapping, and scanning ion imaging (SII) were applied to micro-zircon grains from the Apollo 72255 Civet Cat norite clast. Based on the large number of grains with similarities in internal zoning, habit and trace element geochemistry, and host mineral context, the Civet Cat norite zircons are interpreted to be primary, igneous grains. The chronology obtained for three consecutive surfaces (at different depths) by NanoSIMS, SII, and IMS 1280HR, respectively, indicates that the radiogenic Pb distribution of the Civet Cat norite zircons is heterogeneous among different polished or sputtering surfaces. Forty-two NanoSIMS U-Pb ages (beam size of 5 μm) are concordant on a Wetherill Concordia diagram, and their corresponding 207Pb/206Pb ages spread from 4015 Ma to 4459 Ma. More notably, the six oldest spots of the 42 define a concordant U-Pb age of 4460 ± 31 Ma (2σ, MSWD = 0.47, P = 0.92) and a weighted mean 207Pb/206Pb age of 4453 ± 34 Ma (MSWD = 0.056, P = 0.998). These dates are among the oldest in the lunar highland rocks. However, the 207Pb/206Pb ages of repolished surfaces of these zircons by IMS 1280HR (beam size of 5 μm) do not reproduce the NanoSIMS results (up to 300 Ma younger). The SII (spatial resolution of 2 μm) confirms a heterogeneous distribution of radiogenic Pb within single grains. The EBSD mapping of these zircon grains shows that they have 3–20° of cumulative lattice misorientation. It is proposed that shock-related deformation has facilitated Pb* migration after primordial crystallization. With currently available data, we cannot preclude the possibility that the large errors of the U-Pb ages obscure reverse discordance that would bias our oldest 207Pb/206Pb ages to older values. Conversely, our data could be explained by mixing of Pb-retention and Pb-loss nanodomains as seen in shocked terrestrial zircon such that U-Pb date of 4460 ± 31 Ma approximates the norite formation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
High precision analyses of all four sulfur isotopes in four pyrite and three sphalerite standards and in working reference samples were carried out using a CAMECA NanoSIMS 50L instrument. The ...measurements were made using three different settings of the Faraday cup (FC) and/or electron multiplier (EM) detectors, which meet different requirements for spatial resolution. The effects of EM aging and quasi-simultaneous arrival were corrected before the calibration of instrumental mass fractionation by a standard-sample-standard bracket method using the standards measured together with the samples. High analytical precision was achieved by counting
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Isotopic analyses of sulfur in various sulfide standards and reference samples were carried out using three different modes of detector configuration (FC-FC-FC-EM or FC-EM-EM-EM for
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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 surface
The solar wind (SW)‐derived water could be preserved for hundreds of millions of years if buried at depth
Lunar regolith from the drill core contains considerable water from SW implantation, which is much more accessible
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
China's Chang'e-4 (CE-4) rover landed in Von Kármán crater on January 3, 2019, and has acquired a large amount of data of the landing site. Craters are an important landform in lunar surface and the ...analysis of craters at the landing site with high-resolution images is of great significance for both scientific study and engineering safety. In this study, multi-sources data, including Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (NAC) images, NAC digital elevation model (DEM), Chang'e-2 (CE-2) digital orthophoto map (DOM), SLDEM2015 and stereo images from panoramic cameras onboard the CE-4 rover, are involved to reveal the crater morphologic features at the landing site. The diameter, depth, spatial density and depth/diameter ratio (d/D) of the mapped craters have been investigated. Randomness analysis and the size-frequency distributions of craters in two scales are conducted to thoroughly elaborate the crater distribution in the landing area. The multi-scale crater investigation establishes a foundation for subsequent in-depth studies, e.g., crater evolution and degradation of lunar farside and CE-4 landing area dating.
•We established crater catalogues of the CE-4 landing area in three scales using orbital and rover data.•Spatial density and randomness analysis reveal that distinct secondary craters cover ~1/3 in the 2.4° × 1° landing area.•The d/D of larger and decameter fresh craters indicates the surface and subsurface material is compositionally different.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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.
ABSTRACT Presolar graphite grains have been extensively studied, but are limited in carbonaceous chondrites, particularly in Murchison (CM2) and Orgueil (CI1), which sampled materials from the ...oxidizing regions in the solar nebula. Here, we report the first discovery of presolar graphite grains from the Qingzhen (EH3) enstatite chondrite which formed under a highly reducing condition. Eighteen presolar graphite grains were identified by C-isotope mapping of the low-density fraction (1.75-1.85 g cm−3) from Qingzhen acid residue. Another 58 graphite spherules were found in different areas of the same sample mount using a scanning electron microscope and were classified into three morphologies, including cauliflower, onion, and cauliflower-onion. The Raman spectra of these spherules vary from ordered, disordered, and glassy to kerogen-like, suggestive of a wide range of thermal metamorphisms. NanoSIMS analysis of the C- and Si-isotopes of these graphite spherules confirmed 23 presolar grains. The other 35 graphite spherules have no significant isotopic anomalies, but they share similar morphologies and Raman spectra with the presolar ones. Another three grains were identified during NanoSIMS analysis. Of all the 44 presolar graphite grains identified, six grains show 28Si-excesses, suggestive of supernovae origins, and four grains are 12C- and 29,30Si-rich, consistent with low-metallicity asymptotic giant branch star origins. Another two graphite spherules have extremely low 12C/13C ratios with marginal solar Si-isotopes. The morphologies, Raman spectra, and C- and Si-isotopic distributions of the presolar graphite grains from the Qingzhen enstatite chondrite are similar to those of the low-density fractions from Murchison carbonaceous chondrites. This study suggests a homogeneous distribution of presolar graphite grains in the solar nebula.
It has long been hypothesized that acids formed from anthropogenic pollutants and natural emissions dissolve iron (Fe) in airborne particles, enhancing the supply of bioavailable Fe to the oceans. ...However, field observations have yet to provide indisputable evidence to confirm this hypothesis. Single-particle chemical analysis for hundreds of individual atmospheric particles collected over the East China Sea shows that Fe-rich particles from coal combustion and steel industries were coated with thick layers of sulfate after 1 to 2 days of atmospheric residence. The Fe in aged particles was present as a "hotspot" of (insoluble) iron oxides and throughout the acidic sulfate coating in the form of (soluble) Fe sulfate, which increases with degree of aging (thickness of coating). This provides the "smoking gun" for acid iron dissolution, because iron sulfate was not detected in the freshly emitted particles and there is no other source or mechanism of iron sulfate formation in the atmosphere.
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