The radiometric ages of the returned samples are the cornerstone of lunar cratering chronology models. However, all the previous samples were from the lunar nearside and the radiometric ages of those samples that can be associated with particular surfaces are <4.0 billion years. On 25 June 2024, Chang'e-6 successfully returned 1.935-kilogram samples from the lunar farside. The samples included local basalts with an age of 2807 ± 3 million years and the norites with an age of 4247 ± 5 million years likely corresponding to the age of the South Pole-Aitken basin. With these radiometric ages, we refined the lunar chronology function (CF) and verified that it is still consistent with a combination of an exponential decrease and a linear rate. We further derived the impacting rate and found it supports a smooth decay instead of abrupt changes of the impactor flux at early times. The refined lunar CF can be used to obtain more reliable ages for unsampled lunar areas and provide critical constraint for the lunar early impact history.

The Chang'e-6 (CE-6) mission returned the first lunar farside samples from a basalt unit in the South Pole-Aitken Basin, which can provide novel insights into lunar volcanism. This study investigates the cooling history and source characteristics of the CE-6 low-Ti basalt fragments through the analysis of plagioclase crystal size distribution (CSD) and mineral geochemistry. Most samples indicate single-stage cooling, but a few show multi-stage cooling with microlites (acicular-radiate texture) and megacrysts (tabular-skeletal texture) forming at various rates. The cooling rate estimated by plagioclase CSD analysis ranges from 2.04 to 14.71 degrees C/h, which is slower than those of the Chang'e-5 and Luna-16 basalts, although comparable to the Apollo low-Ti basalts and lunar meteorites. The residence periods vary from 0.6 to 4.29 days, and thermodynamic modeling suggests average burial depths of 0.57 +/- 0.11 m within the lava flow. The equilibrium melt of plagioclase, as estimated by trace element modeling, exhibits low Ba/Sr and La/Sr ratios, indicating that the mantle source is nearly KREEP-free (<0.1%).

Lunar surface water primarily originates from solar wind irradiation, with diurnal variations in its content observed by orbital and ground-based remote sensing. However, low temporal resolution and the lack of accurate in-situ surface observations have limited understanding of the magnitude of these variations. Here, we report analysis results of the in-situ infrared spectra at the same location across different local times acquired by the Chang'e-6 lander. The in-situ spectra were calibrated for thermal contributions based on laboratory measurements conducted on the returned lunar soils, showing clear OH/H2O absorption signals. The OH/H2O contents achieved from the in-situ spectra exhibit significant temporal variations, with a notable decrease of 37%-58% from ∼10:00 a.m. to ∼11:03 a.m. local time. The discovery confirms not only the diurnal water variations detected by remote sensing but also extends such variations to the hourly range. The OH/H2O content decreasing rate is ∼8.4 ± 0.4 ppm/K in the high temperature range (349-358 K), faster than in the low temperature period (∼5.5 ppm/K for 309 K to 319 K). This indicates that temperature exerts a dominant control on the variation of OH/H2O content. Hydrogen exists in various forms in lunar soil grains and solar wind flux over a lunar day is insufficient to replenish the depleted OH/H2O. Therefore, the occurrence of OH/H2O, the only form detectable by infrared spectroscopy, is highly temperature dependent. The new discoveries shed light on the distribution and recycling of water on the lunar surface.

Asteroid impact, playing a key role in shaping the Moon, is a consequence of the orbital dynamical evolution of the Solar System. While the impact flux can be deduced from lunar craters, the impactor populations and their temporal variations remain poorly understood. We analyzed Fe-Ni metals in 40 impact clasts from the Chang'e-6 lunar soils and demonstrated that most of them are asteroidal remnants. The majority of these clasts (27 out of 40) originated from local basalt, where the asteroidal materials were accumulated after basaltic eruption at 2.8 billion years ago (Ga). The remaining 13 clasts are exotic feldspathic materials, delivered from the ancient lunar highlands, preserving asteroid remnants from similar to 4.3 Ga to the present. By classifying the asteroid impactors based on the Ni, Co, P, Ir, and Au contents of the metals, we identified distinct impactor populations for the two clast types. All carbonaceous chondrite metals are exclusively found in seven of the basaltic impact clasts, providing robust evidence for a late-stage bombardment by carbonaceous asteroids. The significant increase in carbonaceous impactors can be attributed to orbital dynamical events between 4.3 and 2.8 Ga, including giant planet migration, the Yarkovsky effect, or breakup of large carbonaceous asteroids. These findings, together with the exponentially declining impact flux, imply that only a small proportion of carbonaceous asteroids were delivered to the early Earth-Moon system, and provide further constraints on the dynamical evolution of the Solar System. Plain LanguageSummaryThe orbitaldynamicevolutionof the Solar Systemis criticalto Earth'shabitabilityand is largelyconstrainedby impactfluxesrecordedin lunar craters.However,the distributionofasteroidimpactortypes-anotherkey parameter-remainspoorlyunderstood.Here, we analyzedindividualiron-nickelmetal grainsin the Chang'e-6impactclasts from two regionsof differentages, to trace possiblechangesin the types of asteroidimpactors.The data reveala significantincreasein the relativeabundanceofcarbonaceousasteroidimpactorsbetween similar to 4.3 and similar to 2.8 Ga. These findingsshed light on the orbitaldynamicsof the early Solar System,and the late bombardmentof carbonaceousasteroidshas importantimplicationsforthe deliveryof water to the early Earth.

Meteorite impact is a key process on the Moon, having profoundly reshaped the lunar surface, modified the physical properties of lunar regolith, and transported water and other volatiles on the surface. However, the temperature-pressure conditions of impact-induced plumes and their duration were poorly constrained. Here, we report the first discovery of immiscibility a FeNi-P-S bead from Chang'e-5 lunar soils, which consists of abundant spherules of metallic FeNi and sulfide both evenly dispersed in phosphide-rich matrix. The observed texture and compositions are consistent with quenching of an FeNi-P-S melt droplet, generated during an iron meteorite impact. The initial droplet was homogeneous and formed at >1800 degrees C and > 11-16 GPa within the impact plume, based on high-pressure experiments of the Fe-P-S system. As the plume expanding, FeNi spherules emerged from the droplet at 11-16 GPa, estimated by P partitioning between the metal and P-S-rich melt. Subsequent separation of the P-S-rich melt into immiscible sulfide-rich spherules and phosphide-rich mesostasis occurred at 1 bar-3 GPa and 1000-1100 degrees C. The duration of the pressure declining from >11-16 GPa to 1 bar-3 GPa was estimated to be 0.5-1 s, combining the impact plume expansion model with the cooling rate inferred from the metallic bead. This study demonstrates that high-pressure conditions of impact plumes can be retained for second timescales, which is critical for chemical reactions and water and other volatile migration on the Moon's surface.

ABSTRACT Formation of the earliest evolved rocks on terrestrial planets remains poorly understood. The ancient Martian regolith breccia meteorite (MRB) contains feldspar-rich clasts, which could be evolved. Here, we report the first discovery of Martian sarcopside within an igneous clast (CS) of MRB. The mineral assemblage, the presence of sarcopside included in chlorapatite, and the equilibrium temperature of 774 ± 20 °C for plagioclase and alkali feldspar in clast CS collectively demonstrate that this clast crystallized from an evolved magma. A new U-Pb zircon age of 4525 ± 66 Ma places crystallization of these feldspar-bearing clasts within the first ∼100 Myr of Martian crust evolution. Furthermore, the equilibrium temperatures of all 16 two-feldspar-bearing clasts observed in small chips of MRB are < 1000 °C, and half are < 800 °C. The low equilibrium temperatures and mineral assemblages of different clasts are consistent with the interpretation that diverse evolved magmatism could have been present on early Mars. These ancient clasts provide a unique window into the timing and thermal regimes of evolved magmatism within the early Martian crust. More importantly, taken together with evidence from evolved lunar samples and asteroidal meteorites, the evolved lithologies on early Mars inferred from MRB indicate that evolved magmatism may have played an important role in the early Solar system.

China's Tianwen-2 mission plans to return samples from a small, rapidly spinning Earth quasi-satellite (469219) Kamo'oalewa. Previous studies linked Kamo'oalewa to lunar composition and origin. Here, we propose another scenario. We reanalyzed the reflectance spectrum of Kamo'oalewa and obtained an absorption band center at 1.001+-0.028 um (error is 1sigma), consistent with LL chondrites. We then conducted space weathering (SW) experiments on meteorites and found that highly space-weathered LL chondrite powder (but not slab) successfully reproduced the reflectance spectrum of Kamo'oalewa. We further traced the dynamical origin of Kamo'oalewa and found that it probably originated from the v6 secular resonance, and more specifically, the Flora family. Kamo'oalewa exhibits a similar composition to Itokawa and 7 objects in the Flora family, but with a higher degree of space weathering. We, therefore, proposed that Kamo'oalewa probably originated from the Flora family and developed an Itokawa-compositional, highly space-weathered, fine-regolith-dominated surface.

The Moon has preserved a unique record of organic matter delivered and reworked by asteroid and comet impacts. Here, we report diverse organic phases (particle-like, adhering-like, and inclusion-like) on the surfaces of lunar regolith grains returned by the Chang'e-5 and Chang'e-6 missions. They are predominantly amorphous carbon-like, containing N- and O-bearing functionalities and amide (─CONH─) linkages. The lunar organics show δD, δ13C, and δ15N values more negative than those of insoluble organic matter reported in carbonaceous chondrites and asteroids, consistent with impact-induced evaporation-condensation and surface reworking. The presence of solar wind implantation signatures in the organics supports long-term exposure on the lunar surface. Together, these findings suggest that the impacts both delivered and chemically processed organic matter on the lunar surface, generating N- and O-bearing functionalities.

China's ongoing Tianwen-2 mission will return samples from a small, rapidly spinning Earth quasi-satellite (469219) Kamo'oalewa. Previous studies linked Kamo'oalewa to lunar composition and origin. Here, we propose another scenario. We reanalyze the reflectance spectrum of Kamo'oalewa and obtain an absorption band center at 1.001 ± 0.028 μm (error is 1σ), consistent with LL chondrites. We then conduct space weathering experiments on meteorites and find that highly space-weathered LL chondrite powder (but not slab) successfully reproduces the reflectance spectrum of Kamo'oalewa. We further trace the dynamical origin of Kamo'oalewa and find that it probably originated from the ν6 secular resonance, and more specifically, the Flora family. Kamo'oalewa exhibits a similar composition to Itokawa and 7 objects in the Flora family, but with a higher degree of space weathering. We, therefore, propose that Kamo'oalewa probably originated from the Flora family and developed an Itokawa-compositional, more space-weathered, fine-regolith-dominated surface.

0 INTRODUCTION China's Chang'E-6 (CE6) mission successfully re-turned the first lunar farside sample from the Apollo Basin(41.625° S,153.978° W) within the South Pole-Aitken(SPA) Basin (Li et al.,2024). Remote sensing datasets and sample analyses indicate that the CE6 soil is a mix-ture of local mare basalts and exotic non-mare compo-nents (Li et al.,2024;Xu et al.,2024;Yue et al.,2024).These exotic non-mare components provide information about the unexplored regions beyond the CE6 landing site. Constraining their chemical compositions and prove-nances is important for expanding our knowledge of the lunar crust's diversity and evolution. Previous bulk and in-situ geochemical analyses of individual clasts have identi-fied a variety of norites in the CE6 soil (e.g.,Cao et al.,2025;Wang et al.,2025). These clasts have contrasting textures and compositions compared with the CE6 mare basalts (He et al.,2025;Zhang et al.,2025;Zhou Q et al.,2025;Cui et al.,2024),and they are considered to derive from multiple impact craters (Gao et al.,2025;Gou et al.,2024). However,these proposed source crater candi-dates have comparable mineral modal abundances and bulk chemical compositions estimated from spectral data-sets (Zhang et al.,2023). Therefore,it's difficult to pre-cisely constrain the source craters of non-mare clasts based on petrographic and geochemical features alone.

The Moon possesses two distinct hemispheres, both of which have undergone space weathering, yet its role on the farside and differences from the nearside remain debated. Here, we present high-precision iron (Fe) and potassium (K) isotopic analyses of lunar soils returned by the Chang'e-6 (CE6) mission. The CE6 bulk and three sieved soils exhibit heavier Fe and K isotopic compositions than the lunar mantle (delta Fe-56 = 0.18 +/- 0.02 parts per thousand to 0.30 +/- 0.02 parts per thousand; delta K-41 = 2.10 +/- 0.04 parts per thousand to 4.67 +/- 0.04 parts per thousand). Such heavy isotopic signatures cannot be explained by the initial soil compositions, meteoritic input, or cosmic-ray effects. Instead, the observed positive correlations of Fe and K isotopes with both particle size and chemical composition indicate the dominant role of space weathering, particularly micrometeoroid impact processes. The heavy Fe and K isotopes indicate a mature nature for the CE6 samples. Based on Ne isotopes, the cosmic-ray exposure age of the CE6 soils is similar to 146 Myr, longer than that of the Chang'e-5 (CE5) soils. Compared to CE5 soils from the nearside at similar latitudes, CE6 soils exhibit heavier Fe isotopic compositions, which can be best explained by their longer exposure history in conjunction with the presence of ancient regolith components formed between 2.8 and 2.0 Ga. Therefore, our results, combined with Si isotopes, suggest that the impact flux at the two landing sites have likely not differed since 2.8 Ga.

Recent studies suggest that the lunar farside experienced a magma ocean evolution similar to that of the nearside. Thus, the nearside-farside dichotomy, such as volcanism and crustal thickness, is likely related to the South Pole-Aitken (SPA) basin-forming impact. Although the noritic clasts found in Chang'e-6 (CE6) samples may originate from crustal remelting induced by the SPA impact, how (and whether) the lunar mantle was modified by this event remains unclear. Here, we present the first high-precision iron (Fe) and potassium (K) isotopic measurements of CE6 low-Ti basalts, revealing higher δ56Fe (0.13 to 0.21‰) and δ41K (0 to 0.09‰) in these basalts compared to their Apollo and Chang'e-5 (CE5) counterparts (δ56Fe: 0 to 0.11‰; δ41K: -0.29 to -0.04‰). The heavy Fe and K isotopic signatures are unlikely to be derived from cosmogenic effects or the addition of impactor-derived materials. Instead, the heavy Fe isotopes can be explained by partial melting and fractional crystallization processes. For K isotopes, however, the data require that the mantle source beneath the SPA basin had a heavier K isotopic composition than that of the nearside mantle, most likely resulting from evaporation caused by the SPA-forming impact. Our results thus provide robust evidence for significant impact-induced modification of the lunar mantle and demonstrate that large-scale impacts may have played a key role in creating lunar asymmetry.

The late accretion of exotic materials is significant in the study of the formation and evolution of the Earth and the Moon. The importance of platinum-group elements (PGEs) in tracking the late accretion stages of planetary formation has long been recognized. In previous studies, estimates of the flux of exotic materials added to the Moon have primarily been based on measurements of siderophile element concentrations in lunar regolith samples returned by the Apollo or Lunar missions. However, due to the analytical limitations at that time, only a few individual siderophile elements, such as Ni, Ir, Ge, Re, and Au, could be quantified. Among these elements, Ni is moderately siderophile, while Ge is moderately volatile, which means neither is the most ideal tracer for identifying the exotic materials in the moon. Advances in analytical techniques have significantly enhanced both the precision and accuracy of measurements for PGEs and Os isotopes. High-precision analytical techniques have established characteristic of PGEs patterns and Os isotope ratios in different meteorite types by ICPMS and TIMS. However, to date, no detailed study has been conducted on PGEs and Os isotopes in mature lunar soil.The CE-5 lunar soil (CE-5LS) collection site is located in an area far from the Apollo and Luna mission regions, and previous studies have confirmed that the surface basalts in the CE-5 sampling area are more than 1 billion years younger than those in the Apollo and Lunar mission regions[1, 2]. This implies that the exotic material flux and composition within the CE-5LS may differ significantly from those in the Apollo lunar soil.In this study, 1100 mg of CE-5LS samples were magnetically separated. And PGEs and Os isotopes were analyzed on the magnetic and non-magnetic fractions, respectively. The results indicate that the influx of exotic material at the CE-5 landing site amounted to approximately 0.8%, markedly lower than estimates based on the accumulation of exotic material in Apollo soil samples (1%–5%)[3-7]. Given that the accumulation of extraterrestrial material on the Moon correlates positively with the Moon's age, this conclusion is reasonable. The PGE patterns and Os isotope ratios in CE-5LS are consistent with those analysed in chondrites. Consequently, the exotic material accrated onto the Moon is predominantly chondrites. AcknowledgmentThe authors had the great honour of applying for and receiving approval to carry out studies on the CE-5 lunar samples allocated by the CNSA. This work was financially supported by the National Key Research and Development Project of China (2020YFA0714804). Reference[1] Che X. C., et al. (2021). Science 374:887.[2] Li Q. L., et al. (2021). Nature 600:54.[3] Ganapathy R., et al. (1970). Geochimica et Cosmochimica Acta Supplement 1:1117.[4] Baedecker P. A., et al. (1974). Lunar and Planetary Science Conference Proceedings 2:1625-1643.[5] Laul J. C., et al. (1974). Lunar and Planetary Science Conference Proceedings 2:1047-1066.[6] Boynton W. V., et al. (1975). Lunar and Planetary Science Conference Proceedings 2:2241-2259.[7] Higuchi H. and Morgan J. W. (1975). Lunar and Planetary Science Conference Proceedings 2:1625-1651.

In-situ stable Mg isotope analysis of olivine, the most common mineral in igneous and metamorphic rocks, provides critical insights into their formation and timescales. However, accurate correction of significant matrix effects is hampered by the lack of olivine reference materials with forsterite (Fo) content below 80. More importantly, current techniques using secondary ion mass spectrometry (SIMS) or laser ablation-multi collector-ICP-MS (LA-MC-ICP-MS) are insufficient to decipher geological processes occurring at fine scales (<10 μm). Here, we report potential olivine reference materials with Fo contents ranging from nearly 0 to 90.8, covering a wide range and displaying homogeneous compositions within individual samples. These reference materials were developed through high-temperature experiments and the collection of extraterrestrial meteorites. Using these materials, we established a method for Mg isotope analysis on a CAMECA NanoSIMS 50L, for the first time achieving a high spatial resolution of ∼1 μm with a precision of 0.7-0.8 ‰ (1SD). We found that the matrix effect is best modelled by a BiHill equation with the 24Mg/(24Mg + 56Fe) ratio. Simultaneous detection of 24Mg-26Mg-28Si-56Fe by NanoSIMS enable us to calibrate the matrix effect online for olivine Mg-isotope analysis. This method was successfully applied to Chang'e-5 (CE5) lunar chemically-zoned olivine crystals, revealing substantial variation of δ26Mg (>4 ‰) on a micron scale (<100 μm).

Environmental conditions, particularly atmospheric pressure and temperature, at the landing of China's Zhurong rover on Mars exhibit diurnal and seasonal variations that can influence laser-induced breakdown spectrometer (LIBS) data acquired by the Mars Surface Composition Detector (MarSCoDe). To assess these effects, experiments with five pressure points (650 to 850 Pa) and three temperature points (-24 degrees C to 5 degrees C) conditions were conducted with the MarSCoDe duplicate model in a Mars environment simulated platform. A diverse set of sample analogs (metals, silicates, carbonates, sulfates, chlorides, oxides, and nitrides) were selected to semiquantitatively analyze the spectral behavior of major, minor, and volatile elements, including Ti, Al, V, Si, Fe, Mg, Ca, Na, K, O, H, B, S, Cl, N, and Mn. In these experiments, our results indicate that a thin atmosphere of >= 650 Pa readily supports high-resolution LIBS spectra, with signal intensities remaining stable or increasing only marginally with rising pressure. In contrast, the subzero temperature at -24 degrees C generally results in reduced signal-to-noise emission intensities, despite the fact that elemental responses are highly matrix-specific. Furthermore, most normalized intensities show significant correlation with the concentrations of elements, and their linear or polynomial models serve as promising calibration references for LIBS data interpretation. This study provides essential baseline data for improving geochemical and habitability evaluations of MarSCoDe results, while additionally informing environmental effects on LIBS systems for Mars missions.

The role of widespread ilmenite in lunar mare regions in the abundance and diurnal variations of surficial OH/H2O remains controversial. Here, we report the water content and hydrogen isotopes in the rims of lunar ilmenites from Chang'e-5 soil samples using an ion microprobe. Ilmenite rims exhibit higher water contents (~730 - 3,700 ppm) and lower δD values (-884 to -482‰) than that of the lunar mantle, indicating a predominantly endogenic origin from solar-wind (SW) implantation. Our data further reveal that although ilmenite and silicate minerals overlap in the δD vs. H2O diagram, almost all ilmenites fall above those of silicates with SW-like δD values. This signature is consistent with the drastic difference in vesicle abundance between ilmenite and silicate minerals. Thus, the lower water content in ilmenite rims most likely reflects a faster dynamic equilibrium between SW-hydrogen implantation and outgassing than in other silicates. These findings suggest that ilmenite may play a critical role in the surface water cycle of lunar maria within the Procellarum KREEP Terrane. This is also crucial for assessing the in-situ resource utilization potential of the region, highlighting the need to reevaluate ilmenite as a viable resource for future lunar exploration.

As the largest and oldest well-preserved impact structure on the Moon, the South Pole-Aitken (SPA) basin on the lunar farside is critical for understanding early solar system dynamics and lunar history, but accurately determining its age remains challenging. Crater-counting chronology and Apollo sample studies propose various SPA-forming ages, which require validation by in situ sampling of the SPA basin. Here, we present the petrology, geochemistry and chronology of norite clasts from the SPA basin that were returned by Chang'e-6. These norites have highly anorthite-rich, rare-earth element-poor plagioclase and magnesium-rich pyroxene, in contrast to Mg-suite norites that were returned from the lunar nearside. Abundant Fe-Ni metals with meteoritic Ni/Co ratios, depletion of volatile elements and variable grain sizes and cooling rates strongly indicate that the norites were crystallized from an impact melt sheet. Precise Pb-Pb ages of zirconium-bearing minerals in the norites yield two distinct impact events at 3.87 and 4.25 Ga. The former represents an impact-resetting event within the basin. The latter finding is most consistent with the age of the SPA impact, providing an initial 4.25-Ga anchor for the older end of the lunar crater chronology and refining the timeline for early lunar evolution.

The lunar magma ocean hypothesis suggests that the primordial KREEP (an acronym of potassium (K), rare earth element (REE), and phosphorus (P)) was the final product of fractional crystallization. However, the primordial KREEP (a.k.a. urKREEP) has never been identified in previous lunar samples or meteorites. The Moon is the focus of many countries' and agencies' space exploration plans, and with the advancement of technology, crewed missions have been proposed. We propose two candidate landing sites, located respectively in the northwest (9.5 degrees W, 0.9 degrees S) and southeast (11.1 degrees W, 6.2 degrees S) of Lalande crater (8.6 degrees W, 4.5 degrees S), for future crewed missions, with the primary goal of sampling the speculated urKREEP. Both sites are situated on the Th- (a critical marker of KREEP) and silica-rich Lalande ejecta in the Mare Insularum and Mare Nubium, respectively. Their geolocations at the low latitude on the lunar nearside, the flat surface, and the low rock abundance suggest the sites are safe for landing and meet the needs of real-time Earth-Moon communication. The astronauts could perform many extravehicular activities, such as collecting KREEP-rich samples, screening clast samples, and drilling regolith cores, to gather a variety of samples, such as Lalande ejecta, basalts, Copernicus ejecta, and regolith. The returned samples are valuable to explore the speculated urKREEP, to reveal the relationship between heat-producing elements and volcanism, to refine the lunar cratering chronology function, and to investigate volatiles in the regolith.