Compound extreme climate events may profoundly affect human activity in the Yangtze River Basin. This study analyzed the long-term spatiotemporal distribution characteristics of compound heatwave-drought and heatwave-waterlogging events in the Yangtze River Basin using multi-period historical observation data and future scenario climate model data. It also examined the changes in population exposure to compound extreme climate events in the basin and their driving factors by combining population statistics and forecast data. The results show that the occurrence days of compound heatwave-drought and heatwave-waterlogging events in the Yangtze River Basin have shown a significant upward trend both in historical periods and future scenarios, accompanied by a marked expansion in the affected areas. Compared to historical periods, population exposure in the Yangtze River Basin under future scenarios is expected to increase by 1.5–2 times, primarily concentrated in the key urban areas of the basin. The main factors driving the changes in population exposure are the increased frequency of extreme climate events and population decline in future scenarios. These findings provide scientific evidence for early mitigation of meteorological disasters in the Yangtze River Basin.

The rhenium-osmium (Re-Os) isotope system is a powerful tool for dating organic-rich sedimentary rocks, yet the mechanisms of Re and Os uptake and their fractionation in different types of organic matter remain poorly understood. Here, we investigate the role of terrestrial organic matter (e. g., wood of the species Taxodium distichum and charcoal generated from the same species in the laboratory) in Re and Os enrichment and isotope fractionation through laboratory experiments. The results show that charcoal has a significantly higher capacity to uptake both Re (68–77 times greater) and Os (1.7–2.2 times higher) compared to wood, with charcoal preferentially accumulating Re over Os, leading to higher ¹⁸⁷Re/¹⁸⁸Os ratios. These findings highlight the important contribution of terrestrial organic matter, particularly charcoal, to Re and Os concentrations and isotope fractionation in shales, and the importance of organic matter type for chelating Re and Os as previously discussed. Furthermore, we discuss the potential of using Re to track organic carbon weathering, noting that the coupled release of Re and organic carbon during weathering provides new insights into carbon cycling processes.

Geothermal heat flow (GHF) is crucial for characterizing the Earth’s thermal state. Compared to other regions worldwide, GHF measurements of South America are relatively sparse for mapping GHF over the continent based on traditional models. Here we apply the machine learning (ML) techniques to predict the GHF in South America. By comparing the global model, ML finds that South American subduction zones are hotter than the global model due to large-scale magmatism, which leads to the higher shallow arc temperatures than canonical thermomechanical and global models. Combining ML model with the local singularity analysis of heat flows, active volcanoes, and igneous rock samples, it is suggested that geothermal anomalies along the Andean Mountain Range are spatially correlated with magmatic activity in the subduction zone. It is concluded that the ML methods may provide reliable GHF prediction in regions like South America, where GHF measurements are limited and uneven.

The Paleo-Pacific Plate stagnated in the mantle transition zone beneath northeast Asia during the Late Mesozoic, resulting in the eastern Asian big mantle wedge (BMW). However, its formation mechanism remains unclear. Here, we analyzed elemental and isotopic compositions of 126–60 Ma intraplate basaltic rocks to map the mantle flow pattern and investigate the implications for the formation of the BMW. These rocks exhibit eastward an increase in Ba/Nb, Ba/La, ⁸⁷Sr/⁸⁶Sr, and ²⁰⁸Pb/²⁰⁴Pb ratios, while a decrease in Nb/Yb, Zr/Yb, Ta/Yb, and Nb/Nb* ratios, indicating mixing between the fertile mantle and the depleted mantle modified by slab material, implying the occurrence of trench-perpendicular mantle flow. The coeval mantle flow and formation of the BMW, the similar directions of mantle flow and Paleo-Pacific Plate subduction, and migration of basin depocenters indicate trench-perpendicular mantle flow was a key factor in the formation of the BMW. Moreover, these basaltic rocks have elevated δ⁶⁶Zn values (0.22‰ to 0.52‰), indicating recycled carbonates have been added into their mantle source, which increased the mantle flow velocity. Combined with slab roll-back in the Late Mesozoic, it created the essential conditions for mantle flow to promote the formation of the eastern Asian BMW.

Coupled dissolution-precipitation is one of the critical processes influencing the mineralogical and geochemical evolution of pegmatites. This mechanism involves the simultaneous dissolution of primary mineral phases and the precipitation of secondary phases, driven by changes in the chemical environment, often mediated by hydrothermal fluids. The Bailongshan Li deposit, located in the West Kunlun region of northwest China, is a significant geological formation known for its rich lithium content and associated rare metals such as tantalum, niobium, and tin. This study investigates the coupled dissolution-precipitation processes that have played a crucial role in the mineralization of this deposit, focusing on key minerals, including cassiterite (Cst), columbite-group minerals (CGM), and elbaite (Elb). Using a combination of petrographic analysis, back-scattered electron (BSE) imaging, cathodoluminescence (CL) imaging, and micro X-ray fluorescence (XRF) mapping, we examined the textural and chemical characteristics of these minerals. Our findings reveal intricate patchy zoning patterns and element distributions (indicated by the Nb, Ta, W, Mn, Fe, Hf, Ti for CGM; Hf, Ti Rb, W, Nb, Ta for Cst; Ti, Zn, Fe, W, Hf, Mn, K for Elb) that indicate multiple stages of mineral alteration driven by fluid-mediated processes. The coupled dissolution-precipitation mechanisms observed in the Bailongshan deposit have resulted in significant redistribution and enrichment of economically valuable elements. The study highlights the importance of hydrothermal fluids in altering primary mineral phases and precipitating secondary phases with distinct compositions. These processes not only modified the mineralogical makeup of the pegmatite but also enhanced its economic potential by concentrating rare metals. Signatures of coupled dissolution-precipitation processes can serve as an essential tool for mineral exploration, guiding the search for high-grade zones within similar pegmatitic formations.

Geological analysis, despite being a long-term method for identifying adverse geology in tunnels, has significant limitations due to its reliance on empirical analysis. The quantitative aspects of geochemical anomalies associated with adverse geology provide a novel strategy for addressing these limitations. However, statistical methods for identifying geochemical anomalies are insufficient for tunnel engineering. In contrast, data mining techniques such as machine learning have demonstrated greater efficacy when applied to geological data. Herein, a method for identifying adverse geology using machine learning of geochemical anomalies is proposed. The method was identified geochemical anomalies in tunnel that were not identified by statistical methods. We by employing robust factor analysis and self-organizing maps to reduce the dimensionality of geochemical data and extract the anomaly elements combination (AEC). Using the AEC sample data, we trained an isolation forest model to identify the multi-element anomalies, successfully. We analyzed the adverse geological features based the multi-element anomalies. This study, therefore, extends the traditional approach of geological analysis in tunnels and demonstrates that machine learning is an effective tool for intelligent geological analysis. Correspondingly, the research offers new insights regarding the adverse geology and the prevention of hazards during the construction of tunnels and underground engineering projects.