Navigating the lunar frontier: one hundred landing sites at the south pole for future mission challenges.

Despite humanity's many lunar missions to the equatorial and mid-latitude regions, the south pole remains uncharted because of its exceptionally harsh conditions. The quest for water ice and the drive to establish lunar bases have positioned the south pole area above 80° latitude, characterized by permanently shaded regions and conducive to water ice preservation. However, the daunting terrain and intricate illumination in this area present significant challenges to engineering safety.

Formation of breccia pipes associated with a hydrogen-rich hydrothermal system on the east Caroline plate in the West Pacific.

A large hydrothermal field at depths >4300 meters was found on the east Caroline plate in the western Pacific Ocean. Here, we show that large hydrothermal pipes with steep walls and breccia-dominated bottoms suggest explosions of billion metric tons of TNT (trinitrotoluene) equivalent. More than 800 short-duration seismic events were detected within 28 days along a 150-kilometer profile, indicating widespread ongoing explosive gas release.

Long-term history of continental weathering and particle transport to the sea.

Here, we explore the long-term history of chemical weathering and particle transport from the continents to the oceans by leveraging the histories of Zr/Al, Rb/Al, and Na/Al in marine sediments over the last 2000 My. We interpret these data in the context of elemental behavior in modern weathering environments and modern marine sediments. We find that from 2000 Mya to ca.

2.2-billion-year-old KREEP-rich volcanism on the Moon.

The Moon's KREEP component-rich in potassium (K), rare earth elements (REE), and phosphorus (P)-is considered a critical heat source sustaining prolonged volcanic activity. However, Chang'e mission samples reveal a lack of KREEP signatures in the sources of mare basalt erupted ∼2.8 and 2.

Argon-based geochronology: advances, limitations and perspectives.

Given that K constitutes about 3 wt.% of Earth's crust and is present in most rock-forming minerals, and that Ar diffusion in minerals is temperature-dependent, Ar-based geochronology (Ar/Ar and K-Ar dating) can date most rocks and also reveal their thermal history. This paper reviews recent advances and longstanding limitations in Ar/Ar and K-Ar geochronology, and provides perspectives into future research on Ar-based geochronometers.

Pulsed biogenic methane emissions coupled with episodic warming during the Toarcian Oceanic Anoxic Event.

Reconstructing carbon release fluxes during ancient climatic warming events is important for improving predictions of carbon cycle and climate dynamics under future anthropogenic warming scenarios. We investigate the extent of biogenic methane release and its contribution to climate variability across the Toarcian Oceanic Anoxic Event (T-OAE) approximately 183 million years ago. To do this, we developed a global biogeochemical model and applied a Bayesian inversion using Markov Chain Monte Carlo (MCMC) simulations.

Abiotic synthesis during the interaction of ferrous chloride-rich silicic fluids with marble under high-grade metamorphic conditions.

Ferrous chloride-rich silicic fluid and melt infiltration led to the decarbonation of dolomitic marble in the Chinese Sulu ultrahigh-pressure metamorphic terrain under temperatures ranging from 670 to 800 °C, pressures from the aragonite + albite to calcite stability fields and the oxygen fugacities between the hematite-magnetite and pyrite-pyrrhotite-magnetite buffers, resulting in the formation of olivine marble and diopsidite. The inclusions in zircons trapped during the decarbonation process suggest that the H-producing reaction 3FeCl (aq) + 3CaCO + HO = FeO (magnetite) + 3CaCl (aq) + 3CO + H occurred and that it induced magnetite-catalyzed Fischer-Tropsch-type synthesis, as indicated by the presence of whewellite, disordered carbonaceous material, CH, and CO in the inclusions. The results of this study highlight the role of aqueous Fe in generating H and magnetite and have far-reaching implications for carbon speciation and solubility in deep fluids and for endogenic abiotic synthesis, which may be pivotal in the prebiotic occurrence of organic compounds on Earth.

H-chain ferritin-based magnetic nanoparticles targeting CD71 for magnetic resonance imaging diagnosis of esophageal squamous cell carcinoma and its precancerous lesions.

Esophageal squamous cell carcinoma (ESCC) represents a globally prevalent malignancy characterized by a poor prognosis, largely due to the challenges that patients face in tolerating invasive diagnostic procedures. Therefore, it is imperative to explore strategies to enhance the early diagnostic rate for patients with ESCC. Based on the property of H-chain ferritin-based magnetic ferritin nanoparticles (M-HFn) as contrast agents that can target cluster of differentiation 71 (CD71), this study provides a comprehensive evaluation of the expression levels and diagnostic potential of CD71 to investigate the feasibility of utilizing M-HFn for non-invasive diagnosis.

Coupled Precipitation-Vegetation Changes Affect Hg Accumulation and Isotope Composition in Loess Records.

Geochemical records from loess-paleosol deposits offer valuable insights into past paleoclimate and paleoecological changes. Here we explore the potential of mercury (Hg) stable isotopes to study the changes of paleoprecipitation and paleovegetation and their causal effect on terrestrial Hg accumulation on the Chinese Loess Plateau (CLP). We first document how variations of Hg concentrations, ΔHg and ΔHg isotope signatures in modern soils and loess are controlled by coupled precipitation-vegetation gradients on the CLP, and unaltered by postdepositional processes.

Widespread ilmenite contributions to the surface water cycle in lunar Procellarum KREEP Terrane.

The role of widespread ilmenite in lunar mare regions in the abundance and diurnal variations of surficial OH/HO 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.

Lens effect of remnant blocks on deep mantle upwelling causing anomalous subsidence.

Classical mantle convection models predict a broad surface uplift over a lower mantle upwelling. However, recent studies have identified anomalously localized surface subsidence above seismically imaged lower mantle upwellings, particularly in regions where upwellings are impeded by subducted/delaminated blocks not currently connected to a subducting/delaminating lithosphere ('remnant blocks' for simplicity), e.g.

Cracking mechanism and acoustic emission characteristics of granite under varying thermal effects.

Understanding the thermo-mechanical behavior of granite under high-temperature conditions is crucial for the safe and efficient development of deep geothermal resources. This study revealed the physico-mechanical properties, cracking mechanism and fracture precursor of granite via compression experiments with acoustic emission (AE) monitoring. Results indicated that 500 °C is the critical temperature for the brittle-ductile transition of granite, characterized by progressive degradation of P-wave velocity, Young's modulus, and uniaxial compressive strength (UCS) with increasing temperature, while peak strain shows an inverse trend.

Protracted circum-continent subduction: A mechanism for craton destruction and a rationale for craton longevity.

The evolution of continents is shaped by the growth and destruction of long-lived cratons, which serve as their stable cores. Processes for craton destruction are controversial because most invoked mechanisms occur frequently throughout Earth history, making the preservation of cratons for billions of years problematic. Here, we address this issue by presenting a crustal-scale analytical signal-amplitude model obtained from high-resolution airborne and shipborne magnetic data across cratons within East Asia.

Lead isotopic evidence for an old and rapid lunar magma ocean.

The Moon's early history remains enigmatic, with intensive debate over the timing and duration of the lunar magma ocean (LMO) and its consequences on the early thermal and chemical evolution of the Moon. Here, we report a lead-lead isochron age of 4406.1 ± 3.

Identification of the exposure pathway to micro-scaled biogenic silica debris via diet and its potential effect in promoting esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) has remained highly prevalent for decades in certain regions, such as the Taihang Mountains in China, though its etiology remains unclear. The previous study unveiled silica fragments in resected ESCC tissues in this region, raising a hypothesis about their relationship with ESCC. Yet, the exposure pathway of these silica fragments and their role in the high incidence of ESCC remain unclear.

A more reduced mantle beneath the lunar South Pole-Aitken basin.

The oxygen fugacity (fO) of the lunar mantle is of pivotal significance in comprehending the formation and evolution of the Moon. However, the fO of the lunar farside mantle remains unknown due to the lack of samples returned from the farside. Here, we determine the oxygen fugacity of 23 basaltic fragments from the Chang'e-6 (CE6) soil, the first farside sample collected from the South Pole-Aitken (SPA) basin.

CSAMT-Driven Feasibility Assessment of Beishan Underground Research Laboratory.

The safe disposal of high-level radioactive waste (HLW) is imperative for sustaining China's rapidly expanding nuclear power sector, with deep geological repositories requiring rigorous site evaluation via underground research laboratories (URLs). This study presents a controlled-source audio-frequency magnetotellurics (CSAMT) survey at the Xinchang site in China's Beishan area, a region dominated by high-resistivity metamorphic rocks. To overcome electrical data acquisition challenges in such resistive terrains, salt-saturated water was applied to transmitting and receiving electrodes to enhance grounding efficiency.

Mechanical Properties and Microstructures of Solid Waste Composite-Modified Lateritic Clay via NaOH/NaCO Activation: A Sustainable Recycling Solution of Steel Slag, Fly Ash, and Granulated Blast Furnace Slag.

The utilization of steel slag (SS), fly ash (FA), and ground granulated blast furnace slag (GGBFS) as soil additives in construction represents a critical approach to achieving resource recycling of these industrial by-products. This study aims to activate the SS-FA-GGBFS composite with a NaOH solution and NaCO and employ the activated solid waste blend as an admixture for lateritic clay modification. By varying the concentration of the NaOH solution and the dosage of NaCO relative to the SS-FA-GGBFS composite, the effects of these parameters on the activation efficiency of the composite as a lateritic clay additive were investigated.

An improved system and analytical method for determining oxygen isotopes in O-enriched water samples.

The spatiotemporal differences in the hydrogen and oxygen isotopic composition of water offer a powerful technical approach for research on the water cycle, paleoclimate reconstruction, and water source identification. Hydrogen and oxygen isotopes in certain specialized samples, such as O-enriched water, have been utilized in food science, environmental ecology, and medical research. To address the low efficiency of traditional offline HO-CO equilibrium methods and the pronounced memory effect associated with continuous-flow techniques for O-enriched water samples, we propose a novel analytical system and methodology for oxygen isotope determination in water.

Microwave Curing of FA- and MK-Based Geopolymer Gels: Effects on Pore Structure, Mechanical Strength, and Heavy Metal Leachability.

Microwave curing has proven to be a highly effective method for enhancing the structural integrity, compressive strength, and heavy metal immobilization performance of geopolymer (GP) gels. For fly ash-based GP gels, optimal compressive strength (126.84 MPa) and minimal heavy metal ion leaching (0.

Acid Fractionation Factor of Oxygen Isotopes in Mixed Calcite-Dolomite Samples: Implications for Data Correction.

Rationale: The conventional method for measuring carbon and oxygen isotopes in carbonates involves the reaction of carbonate minerals with phosphoric acid (PPA) to generate CO, followed by purification and isotopic analysis. During this reaction, a temperature-dependent oxygen isotope acid fractionation factor (AFF) is introduced, as not all oxygen is released in CO. Although the temperature dependence of AFF has been extensively studied in pure carbonate minerals, little research has been conducted on AFF variations in mixed carbonate minerals with diverse chemical and mineralogical compositions.

Experimental characterization and grain-based numerical modeling of multiscale fracture mechanisms in pre-fractured granite.

The mechanical behavior of pre-fractured granite is primarily governed by pre-existing fractures, in which macro-crack evolution emerges from micro-crack accumulation. This study employs an integrated approach combining mechanical testing, acoustic emission (AE) monitoring, and multiscale numerical simulations to systematically investigate the deformation and failure mechanisms of granite containing single and double pre-existing fractures. Key findings reveal: (1) Fracture geometry dictates strength: Uniaxial compressive strength (UCS) increases with fracture inclination angle, whereas elastic modulus remains relatively constant.

GSK-3β and mTOR Phosphorylation Mediate the Reversible Regulation of Hypomagnetic Field on Adult Neural Stem Cell Proliferation.

Exposure to hypomagnetic field (HMF) of < 5 μT has been demonstrated to impair cognitive behaviors in mammals by disrupting neurogenesis. This process could potentially be modulated by the protein phosphorylation of adult neural stem cells (aNSCs) that are highly sensitive to environmental changes. However, the effects of HMF on aNSCs protein phosphorylation remain unclear.