Yuchen Xu

Chinese Academy of Sciences | CAS · National Space Science Center

Baddeleyite (ZrO2) is widespread in lunar basalts and frequently used for U‐Pb geochronology of magmatic and impact events. The formation of baddeleyite involves two primary mechanisms: (a) crystallization from late‐stage magma, and (b) decomposition of zircon under high‐temperature (high‐T) conditions. Baddeleyite with distinct formation mechanism...

The Apollo basin, located in the northeastern part of the South Pole-Aitken (SPA) basin, represents one of the Moon's most significant geological features, offering profound insights into the lunar interior structure, the effects of the SPA impact, and the history of lunar crust evolution. This study presents an in-depth geological analysis of the...

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....

The lunar surface and interior are highly reducing, resulting in the virtually absence of ferric ion. However, recent studies suggest the presence of ferric iron in lunar samples, and in most cases they were found in amorphous silicates (e.g., glass beads) measured by TEM–EELS. In this work, we conducted a systematic TEM–EELS analysis on the iron v...

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’...

Remote sensing data revealed that the presence of water (OH/H2O) 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 surfac...

Chang'E-5 (CE-5) landed in the northeast of the Oceanus Procellarum and successfully returned ∼1.73 kg lunar samples from a distinctively young mare basalt unit. The reflectance spectra between 0.45 μm to 3.20 μm at the landing site were acquired by the onboard Lunar Mineralogical Spectrometer before and after the sampling. The results from the spe...

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 an...

The solar system could be separated into two zones based on the isotopic dichotomy between non-carbonaceous and carbonaceous groups, with the latter likely accreted in the outer solar system. Among carbonaceous groups, the CM chondrite contains high abundances of organic carbon and water. They have undergone aqueous alteration, thermal metamorphism...

Plain Language Summary The lunar surface has been suffering intense meteorite impacts and solar wind irradiation for billions of years, which heavily modifies its physical properties, chemical compositions and mineralogical features, and in turn, the optical reflectance spectra of the Moon. The meteorite impacts are random events, but the intensity...

To investigate the distribution of solar-wind implanted H in the low latitude regions of the lunar surface, we carried out NanoSIMS depth-profiling measurements of H isotope and water content on Apollo 11 soils that were stored in the Geological Museum, Institute of Geology and Geophysics, Chinese Academy of Sciences. The results show that the surf...

Each type of asteroids and comets are important, serving as the unique puzzle pieces of the solar system. The countless number of small bodies spread vastly from the near-Earth orbits to the main belt and beyond Jupiter. Thus, in order to complete the whole puzzle, and hence requires a well-designed roadmap of sample return (SR) missions and intern...

NanoSIMS has been the most widely used analytical technique for measuring the elemental and isotopic ratios of micrometer to sub‐micrometer particles, e.g., pre‐solar grains, soil particles, and fog‐helium aerosol particles. Automated sample stage movement combined with particle recognition algorithm is commonly used to improve analytical efficienc...

Abstract There are growing demands for integrated study of isotopes, trace elements and crystallography of micron-sized grains observed on polished sections or scattered on surface of sample holders. However, transmission electron microscopy (TEM) observation is largely restricted by the challenges associated with the preparation of ultrathin secti...

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...

We performed an in-depth exploration of the Al–Mg system for presolar graphite, SiC, and Si3N4 grains found to contain large excesses of 26Mg, indicative of the initial presence of live 26Al. Ninety of the more than 450 presolar grains processed in this study contain well-correlated ${\delta }^{26}\mathrm{Mg}{/}^{24}\mathrm{Mg}$ and 27Al/24Mg ratio...

Significance After the Apollo and Luna missions, which were flown about 40 years ago, the Moon was explored only from orbit. In addition, no samples were returned from the young and high-FeO and TiO 2 mare basalt in the northern Imbrium basin. Such samples are important to understand the formation and evolution of the Procellarum KREEP [potassium (...

We report C, Si, N, S, Mg-Al, and Ca-Ti isotopic compositions of presolar silicon carbide (SiC) grains from the SiC-rich KJE size fraction (0.5-0.8 μm) of the Murchison meteorite. One thousand one hundred thirteen SiC grains were identified based on their C and Si isotopic ratios. Mainstream, AB, C, X, Y, and Z subtypes of SiC, and X-type silicon n...

Two petrographic settings of carbonaceous components, mainly filling open fractures and occasionally enclosed in shock-melt veins, were found in the recently fallen Tissint Martian meteorite. The presence in shock-melt veins and the deuterium enrichments (δD up to +1183‰) of these components clearly indicate a pristine Martian origin. The carbonace...