Regolith, widely distributed on the Earth’s surface, constitutes a significant compartment of the Critical Zone, resulting from intricate interactions among the atmosphere, lithosphere, hydrosphere, and biosphere. Regolith formation critically influences nutrient release, soil production, and long-term climate regulation. Regolith development is governed by two primary processes: production and denudation. An urgent need exists to comprehensively understand these processes to refine our understanding of Critical Zone functions. This study investigates an in-situ regolith profile developed on granitic bedrock from a tropical region (Sanya, China). We conducted geochemical analyses, encompassing major, trace elements and mineralogical compositions as well as U-series isotopes, and applied the U-series disequilibrium method to investigate the formation history of this profile. Alternatively, dividing the regolith profile into sub-weathering zones provides a better explanation for the geochemical results, and a multi-stage model based on this subdivision effectively interprets the evolution of deep regolith. Utilizing this multi-stage model, regolith production rates is derived from the “gain and loss” model, ranging from 1.27 ± 0.03 to 42.42 ± 24.24 m/Ma. The production rates first increase from surface until a maximum rate is reached at the depth of ∼ 160 cm and then decrease at further deeper horizons along the depth profile, and the variation of production rates follows a so-called “humped function”. This pioneering investigation into regolith production rates in the Chinese tropical region indicates that (1) the studied profile deviates from a steady state compared to the denudation rate derived from cosmogenic nuclides (¹⁰Be_in-situ); (2) subdividing the deep profile based on geochemical data and U-series isotopic activity ratios is imperative for accurately determining regolith production rates; and (3) the combination of U-series disequilibrium and cosmogenic nuclides robustly evaluates the quantitative evolution state of regolith over long time scales.

The Tasmanian microcontinent, situated along the East Gondwana accretionary margin during the late Neoproterozoic and early Palaeozoic, contains an unequivocal high-pressure metamorphic record comprising key information pertaining to the geodynamics of subduction along the margin. Subduction of the Tasmanian microcontinent is interpreted by some as a response to back-arc basin inversion prior to ophiolite obduction and high-pressure metamorphism during the Cambrian Tyennan Orogeny. However, thermobarometric evidence in support of such a model from rocks once positioned on the subducting continental margin is lacking. Despite occurrences of eclogite-facies mineral assemblages in the strongly deformed Tyennan Region of western Tasmania, garnet-bearing quartzofeldspathic assemblages documented in metasedimentary lithologies from the remote south-west coast of Tasmania have been interpreted as an expression of low- to moderate-pressure metamorphism. We report a strongly overprinted chlorite-quartz-garnet-bearing assemblage from the southern Tyennan Region (Nye Bay) which shows evidence for high-pressure metamorphism. Coarse-grained garnet porphyroblasts contain inclusions of kyanite, muscovite, and rutile, and yield in-situ Lu–Hf dates of c. 520 Ma. The cm-scale garnet porphyroblasts are zoned in the major and trace elements, preserving core-rim compositional gradients reflecting garnet growth up-pressure. Aided by mineral equilibria forward modelling, the garnet rim compositions and the Zr content of Cambrian rutile constrain peak metamorphic conditions of ∼ 17.5–19 kbar and ∼ 780–820 °C, equivalent to warm subduction thermal gradients between 410–470 °C/GPa. Garnet core compositions and the Ti content of quartz inclusions in the garnet cores constrain the pressures and temperatures for garnet nucleation to ∼ 6–7 kbar and ∼ 560–580 °C, corresponding to relatively high prograde thermal gradients between 800–965 °C/GPa. The thermal gradients determined from the south-west Tasmanian metamorphic record provide a direct window into the progressive evolution of the thermal state of the Cambrian subduction system, with the physical conditions of garnet nucleation potentially reflecting those of subduction initiation. The corresponding warm thermal gradients provide evidence for subduction initiation driven by the collapse of a pre-orogenic back-arc. This interpretation is consistent with an existing tectonic model for the Tyennan Orogeny which proposes a back-arc basin origin for the protoliths to the western Tasmanian sub-ophiolitic metamorphic sole.

The application of machine learning for pyrite discrimination establishes a robust foundation for constructing the ore-forming history of multi-stage deposits; however, published models face challenges related to limited, imbalanced datasets and oversampling. In this study, the dataset was expanded to approximately 500 samples for each type, including 508 sedimentary, 573 orogenic gold, 548 sedimentary exhalative (SEDEX) deposits, and 364 volcanogenic massive sulfides (VMS) pyrites, utilizing random forest (RF) and support vector machine (SVM) methodologies to enhance the reliability of the classifier models. The RF classifier achieved an overall accuracy of 99.8%, and the SVM classifier attained an overall accuracy of 100%. The model was evaluated by a five-fold cross-validation approach with 93.8% accuracy for the RF and 94.9% for the SVM classifier. These results demonstrate the strong feasibility of pyrite classification, supported by a relatively large, balanced dataset and high accuracy rates. The classifier was employed to reveal the genesis of the controversial Keketale Pb-Zn deposit in NW China, which has been inconclusive among SEDEX, VMS, or a SEDEX-VMS transition. Petrographic investigations indicated that the deposit comprises early fine-grained layered pyrite (Py1) and late recrystallized pyrite (Py2). The majority voting classified Py1 as the VMS type, with an accuracy of RF and SVM being 72.2% and 75%, respectively, and confirmed Py2 as an orogenic type with 74.3% and 77.1% accuracy, respectively. The new findings indicated that the Keketale deposit originated from a submarine VMS mineralization system, followed by late orogenic-type overprinting of metamorphism and deformation, which is consistent with the geological and geochemical observations. This study further emphasizes the advantages of Machine learning (ML) methods in accurately and directly discriminating the deposit types and reconstructing the formation history of multi-stage deposits.

Hurricanes are one of the most destructive natural disasters that can cause catastrophic losses to both communities and infrastructure. Assessment of hurricane risk furnishes a spatial depiction of the interplay among hazard, vulnerability, exposure, and mitigation capacity, crucial for understanding and managing the risks hurricanes pose to communities. These assessments aid in gauging the efficacy of existing hurricane mitigation strategies and gauging their resilience across diverse climate change scenarios. A systematic review was conducted, encompassing 94 articles, to scrutinize the structure, data inputs, assumptions, methodologies, perils modelled, and key predictors of hurricane risk. This review identified key research gaps essential for enhancing future risk assessments. The complex interaction between hurricane perils may be disastrous and underestimated in the majority of risk assessments which focus on a single peril, commonly storm surge and flood, resulting in inadequacies in disaster resilience planning. Most risk assessments were based on hurricane frequency rather than hurricane damage, which is more insightful for policymakers. Furthermore, considering secondary indirect impacts stemming from hurricanes, including real estate market and business interruption, could enrich economic impact assessments. Hurricane mitigation measures were the most under-utilised category of predictors leveraged in only 5% of studies. The top six predictive factors for hurricane risk were land use, slope, precipitation, elevation, population density, and soil texture/drainage. Another notable research gap identified was the potential of machine learning techniques in risk assessments, offering advantages over traditional MCDM and numerical models due to their ability to capture complex nonlinear relationships and adaptability to different study regions. Existing machine learning based risk assessments leverage random forest models (42% of studies) followed by neural network models (19% of studies), with further research required to investigate diverse machine learning algorithms such as ensemble models. A further research gap is model validation, in particular assessing transferability to a new study region. Additionally, harnessing simulated data and refining projections related to demographic and built environment dynamics can bolster the sophistication of climate change scenario assessments. By addressing these research gaps, hurricane risk assessments can furnish invaluable insights for national policymakers, facilitating the development of robust hurricane mitigation strategies and the construction of hurricane-resilient communities. To the authors’ knowledge, this represents the first literature review specifically dedicated to quantitative hurricane risk assessments, encompassing a comparison of Multi-criteria Decision Making (MCDM), numerical models, and machine learning models. Ultimately, advancements in hurricane risk assessments and modelling stand poised to mitigate potential losses to communities and infrastructure both in the immediate and long-term future.

The investigations of physical attributes of oceans, including parameters such as heat flow and bathymetry, have garnered substantial attention and are particularly valuable for examining Earth’s thermal structures and dynamic processes. Nevertheless, classical plate cooling models exhibit disparities when predicting observed heat flow and seafloor depth for extremely young and old lithospheres. Furthermore, a comprehensive analysis of global heat flow predictions and regional ocean heat flow or bathymetry data with physical models has been lacking. In this study, we employed power-law models derived from the singularity theory of fractal density to meticulously fit the latest ocean heat flow and bathymetry. Notably, power-law models offer distinct advantages over traditional plate cooling models, showcasing robust self-similarity, scale invariance, or scaling properties, and providing a better fit to observed data. The outcomes of our singularity analysis concerning heat flow and bathymetry across diverse oceanic regions exhibit a degree of consistency with the global ocean spreading rate model. In addition, we applied the similarity method to predict a higher resolution (0.1° × 0.1°) global heat flow map based on the most recent heat flow data and geological/geophysical observables refined through linear correlation analysis. Regions displaying significant disparities between predicted and observed heat flow are closely linked to hydrothermal vent fields and active structures. Finally, combining the actual bathymetry and predicted heat flow with the power-law models allows for the quantitative and comprehensive detection of anomalous regions of ocean subsidence and heat flow, which deviate from traditional plate cooling models. The anomalous regions of subsidence and heat flow show different degrees of anisotropy, providing new ideas and clues for further analysis of ocean topography or hydrothermal circulation of mid-ocean ridges.

Energy poverty in developing countries is a critical issue characterized by the lack of access to modern energy services, such as electricity and clean cooking facilities, as marked in SDG 7. This study explores the correlations between energy poverty, energy intensity, resource abundance, and income inequality, as these factors have been theorized to play important roles in influencing energy poverty in developing countries. By observing that the dataset is heterogeneous across the countries and over the time frame, we use the Method of Moments Quantile Regression (MMQR) to analyze our developing countries’ data from 2000 to 2019. Our findings indicate that energy intensity is a significant factor influencing energy poverty, suggesting that higher energy consumption relative to the sample countries can exacerbate this issue. Additionally, we observe that income inequality within the sample countries is a critical determinant of energy poverty levels, highlighting the dynamics between economic disparity and access to energy resources. Interestingly, our study reveals that resource abundance acts as a blessing rather than a curse in terms of energy poverty, implying that countries rich in natural resources may have better opportunities to combat energy deprivation. Finally, we emphasize the vital role of financial markets in addressing energy poverty on a global scale, suggesting that robust financial systems can facilitate investments and innovations aimed at improving energy access for vulnerable populations. The results from the robustness supports the empirical results obtained from the main estimation. The empirical findings of the present study advance important comprehensions for policymakers to adopt energy policies that address the complex challenges of energy poverty and promote inclusive energy access.

Cold seeps are oases for biological communities on the sea floor around hydrocarbon emission pathways. Microbial utilization of methane and other hydrocarbons yield products that fuel rich chemosynthetic communities at these sites. One such site in the cold seep ecosystem of Krishna-Godavari basin (K-G basin) along the east coast of India, discovered in Feb 2018 at a depth of 1800 m was assessed for its bacterial diversity. The seep bacterial communities were dominated by phylum Proteobacteria (57%), Firmicutes (16%) and unclassified species belonging to the family Helicobacteriaceae. The surface sediments of the seep had maximum OTUs (operational taxonomic units) (2.27 × 10³) with a Shannon alpha diversity index of 8.06. In general, environmental parameters like total organic carbon (p < 0.01), sulfate (p < 0.001), sulfide (p < 0.05) and methane (p < 0.01) were responsible for shaping the bacterial community of the cold seep ecosystem in the K-G Basin. Environmental parameters play a significant role in changing the bacterial diversity richness between different cold seep environments in the oceans.

In this study, the advanced machine learning algorithm NESTORE (Next STrOng Related Earthquake) was applied to the Japan Meteorological Agency catalog (1973–2024). It calculates the probability that the aftershocks will reach or exceed a magnitude equal to the magnitude of the mainshock minus one and classifies the clusters as type A or type B, depending on whether this condition is met or not. It has been shown useful in the tests in Italy, western Slovenia, Greece, and California. Due to Japan’s high and complex seismic activity, new algorithms were developed to complement NESTORE: a hybrid cluster identification method, which uses both ETAS-based stochastic declustering and deterministic graph-based selection, and REPENESE (RElevant features, class imbalance PErcentage, NEighbour detection, SElection), an algorithm for detecting outliers in skewed class distributions, which takes in account if one class has a larger number of samples with respect to the other (class imbalance).

We document, for the first time, Mesoproterozoic-aged, continental arc magmatism in the Tasmanides. Granitoid samples intruding the Proterozoic Cape River Metamorphics in northeast Queensland contain abundant ∼ 1200 Ma igneous zircons, with early-Paleozoic metamorphic rim overgrowths. Analytical mixing between the igneous and metamorphic zircons produces cryptic discordant analyses, but the origin of said discordance is resolved with zircon Th/U ratios. Samples of the Fat Hen Creek Complex are peraluminous, calc-alkaline, S-type granitoids, that record high-grade metamorphism and trace element mobilization. The P3 and P42 intrusions are metaluminous, calc-alkaline, I-type granodiorite, which intruded the Cape River Metamorphics, and contain trace element signatures consistent with a continental-arc setting. We propose that a Mesoproterozoic continental terrane, herein referred to as the Oakvale Province, exists as basement to the Thomson Orogen. We propose several models for the formation of the Oakvale Province, with potential links to the Tarim Block, and the Yangtze Craton, during the late-Mesoproterozoic. We propose that the Oakvale Province supplied the Tasmanides with late-Mesoproterozoic detritus, and that such detritus was not solely sourced from the Musgrave Province as previously interpreted. Finally, we interpret the oroclinal bending of Paleozoic deformation and plutonic fabrics to reflect the buried extent of the Oakvale Province, and to potentially map out the Neoproterozoic rift margin associated with Rodinia break-up.

Subduction zones are critical interfaces for lithospheric volatile fluxes, where complex tectonic and geochemical interactions facilitate the release of gases and fluids from deep-seated reservoirs within the Earth’s crust. Mud volcanism, as a dynamic manifestation of these processes, contributes CH₄ emissions that influence the global methane budget and impact marine ecosystems. Although ∼2000 CH₄-rich mud extrusions have been documented in subduction zones globally, the geological origins and subduction-related geochemical and tectonic mechanisms driving these emissions remain poorly understood. This research examines the Makran subduction zone which hosts one of the world’s largest accretionary wedge and extensive CH₄-rich mud extrusions, as a model system. Integrated geochemical, geophysical, and geological observations reveal that thermogenic CH₄ and clay-rich fluidized muds originate from deeply buried Himalayan turbidites (underthrusted sediments), driven by organic-rich sediment maturation and high fluid overpressure. Key tectonic features, including thrust faults, overburden pressure of wedge-top sediments, normal faults, brittle fractures, and seismicity, facilitate CH₄-rich mud extrusions into the hydrosphere and atmosphere. The extruded gases are predominantly CH₄, with minor C₂H₆, C₃H₈, i-C₄H₁₀, and n-C₄H₁₀ while the mud breccia exhibits a chemical composition dominated by SiO₂, Al₂O₃, and Fe₂O₃, enriched with trace elements (Rb, Zr, and V) and clay minerals, quartz, and carbonates. Geochemical indicators suggest intense chemical weathering and mature sediments classifying the mud breccia as litharenite and sub-litharenite, indicative of deep burial and compaction. These findings model the evolution of CH₄-rich mud extrusions through three geological stages: (i) Eocene to Early Miocene pre-thermogenic formation of the CH₄-rich source, (ii) Middle Miocene to Pliocene syn-thermogenic CH₄ and fluidized mud generation, and (iii) Pleistocene to Recent post-thermogenic CH₄-rich fluidized mud migration. These findings underscore the critical yet often overlooked role of subduction-related geochemical and tectonic processes in CH₄ generation and emission, with significant implications for the global CH₄ budget and marine ecosystems.

The Kunene Complex (KC) represents a very large Mesoproterozoic igneous body, mainly composed of anorthosites and gabbroic rocks that extends from SW Angola to NW Namibia (outcropping 18,000 km2 , NE-SW trend, and ca. 350 km long and up to 50 km wide). Little is known about its structure at depth. Here, we use recently acquired aerogeophysical data to accurately determine its hidden extent and to unravel its morphology at depth. These data have been interpreted and modelled to investigate the unexposed KC boundaries, reconstructing the upper crustal structure (between 0 and 15 km depth) over-lain by the thin sedimentary cover of the Kalahari Basin. The modelling reveals that the KC was emplaced in the upper crust and extends in depth up to ca. 5 km, showing a lobular geometry and following a large NE-SW to NNE-SSW linear trend, presumably inherited from older Paleoproterozoic structures. The lat-eral continuation of the KC to the east (between 50 and 125 km) beneath the Kalahari Cenozoic sediments suggests an overall size three times the outcropping dimension (about 53,500 km²). This affirmation clearly reinforces the economic potential of this massif, related to the prospecting of raw materials and certain types of economic mineralization (Fe-Ti oxides, metallic sulphides or platinum group miner-als). Up to 11 lobes have been isolated with dimensions ranging from 135.5 to 37.3 km in length and 81.9 to 20.7 km in width according to remanent bodies revealed by TMI mapping. A total volume of 65,184 km³ was calculated only for the magnetically remanent bodies of the KC. A long-lasting complex contractional regime, where large strike-slip fault systems were involved, occurred in three kinematic pulses potentially related to a change of velocity or convergence angle acting on previous Paleoproterozoic inherited sutures. The coalescent magmatic pulses can be recognized by means of mag-netic anomalies, age of the bodies as well as the lineations inferred in this work: (i) Emplacement of the eastern mafic bodies and granites in a stage of significant lateral extension in a transtensional context between 1500 Ma and 1420 Ma; (ii) Migration of the mantle derived magmas westwards with deforma-tion in a complex contractional setting with shearing structures involving western KC bodies and base-ment from 1415 Ma to 1340 Ma; (iii) NNW-SSE extensional structures are relocated westwards, involving mantle magmas, negative flower structures and depression that led to the formation of late Mesoproterozoic basins from 1325 Ma to 1170 Ma. Additionally, we detect several first and second order structures to place the structuring of the KC in a craton-scale context in relation to the crustal structures detected in NW Namibia.

It has been shown that the age of minerals in which U ± Th are a major (e.g., uraninite, pitchblende and thorite) or minor (e.g., monazite, xenotime) component can be calculated from the concentrations of U ± Th and Pb rather than their isotopes, and such ages are referred to as chemical ages. Although equations for calculating the chemical ages have been well established and various computation programs have been reported, there is a lack of software that can not only calculate the chemical ages of individual analytical points but also provide an evaluation of the errors of individual ages as well as the whole dataset. In this paper, we develop a software for calculating and assessing the chemical ages of uranium minerals (CAUM), an open-source Python-based program with a friendly Graphical User Interface (GUI). Electron probe microanalysis (EPMA) data of uranium minerals are first imported from Excel files and used to calculate the chemical ages and associated errors of individual analytical points. The age data are then visualized to aid evaluating if the dataset comprises one or multiple populations and whether or not there are meaningful correlations between the chemical ages and impurities. Actions can then be taken to evaluate the errors within individual populations and the significance of the correlations. The use of the software is demonstrated with examples from published data.

At the end of the Cretaceous period, 66 million years ago, the 7 − 19 km diameter Chicxulub asteroid hit the Yucatan Peninsula in Mexico, triggering global catastrophic environmental changes and mass extinction. The contributions of this event towards changes in plate and plume geodynamics are not fully understood. Here we present a range of geological observations indicating that the impact marked a tectonic turning point in the behavior of mantle plume and plate motion in the Caribbean region and worldwide. At a regional scale, the impact coincides with the termination of seafloor spreading in the Caribbean Ridge. Shortly after the Cretaceous–Paleogene transition, magmatism associated with the Caribbean Large Igneous Province waned, and intensive Paleogene volcanism was initiated. These events happened synchronously with anomalously high mid-ocean ridge magmatism worldwide and an abrupt change in the relative motion of the South American and North American tectonic plates. The evidence for such abrupt changes in plate kinematics and plume behavior raises the possibility that the Chicxulub impact triggered a chain of effects that modified melt reservoirs, subducting plates, mantle flows, and lithospheric deformation. To explain how an asteroid impact could modify tectonic behavior, we discuss two end-member mechanisms: quasi-static and dynamic triggering mechanisms. We designed a numerical model to investigate the strain field and the relative plate motion before and after the impact. The model predicts an enhanced deformation associated with the impact, which surficially tapers off ∼ 500 km from the crater. The impact modifies the subjacent mantle flow field, contributing to long-term mantle-driven dynamic changes. Additionally, deformation associated with seismic effects may have contributed to far-field effects and global changes. We conclude that large asteroid impacts, such as the Chicxulub collision, could trigger cascading effects sufficient to disrupt and significantly modify plate geodynamics.

Understanding spatial heterogeneity in groundwater responses to multiple factors is critical for water resource management in coastal cities. Daily groundwater depth (GWD) data from 43 wells (2018–2022) were collected in three coastal cities in Jiangsu Province, China. Seasonal and Trend decomposition using Loess (STL) together with wavelet analysis and empirical mode decomposition were applied to identify tide-influenced wells while remaining wells were grouped by hierarchical clustering analysis (HCA). Machine learning models were developed to predict GWD, then their response to natural conditions and human activities was assessed by the Shapley Additive exPlanations (SHAP) method. Results showed that eXtreme Gradient Boosting (XGB) was superior to other models in terms of prediction performance and computational efficiency (R² > 0.95). GWD in Yancheng and southern Lianyungang were greater than those in Nantong, exhibiting larger fluctuations. Groundwater within 5 km of the coastline was affected by tides, with more pronounced effects in agricultural areas compared to urban areas. Shallow groundwater (3–7 m depth) responded immediately (0–1 day) to rainfall, primarily influenced by farmland and topography (slope and distance from rivers). Rainfall recharge to groundwater peaked at 50% farmland coverage, but this effect was suppressed by high temperatures (>30 °C) which intensified as distance from rivers increased, especially in forest and grassland. Deep groundwater (>10 m) showed delayed responses to rainfall (1–4 days) and temperature (10–15 days), with GDP as the primary influence, followed by agricultural irrigation and population density. Farmland helped to maintain stable GWD in low population density regions, while excessive farmland coverage (>90%) led to overexploitation. In the early stages of GDP development, increased industrial and agricultural water demand led to GWD decline, but as GDP levels significantly improved, groundwater consumption pressure gradually eased. This methodological framework is applicable not only to coastal cities in China but also could be extended to coastal regions worldwide.

The Tongshan porphyry Cu deposit is well known as one of the most economically significant porphyry deposits in northeast China. Recently, Tongshan has become the largest porphyry Cu deposit in northeast China with the successful exploration of the concealed ore zone V. Ore zone V has the largest Cu tonnage (562 Mt @ 0.50% Cu) and extends into the eastern segment at Tongshan. Compared with ore zones I–III, which are hosted within granitic rocks in the western segment, the ore zone V mainly occurs in Duobaoshan volcanic rocks and the roof pendants of newly discovered intrusions. Here, we conducted a study of the understudied eastern ore zone and found that copper mineralization is associated with the newly discovered suites in the eastern segment at Tongshan. Two periods of ore-bearing quartz veins with different widths have been recognized, including quartz-chalcopyrite-pyrite veinlets (0.1–0.2 cm) and quartz-chalcopyrite-polymetallic sulfide wide veins (>0.5 cm). The latter veins can be divided into four stages (I–IV) of mineralization and alteration, which are closely related to the newly discovered granodiorite and dacite porphyry. Our new zircon U–Pb ages show that the granodiorite and dacite porphyry were developed between 228–223 Ma, suggesting that the overprinting porphyry copper mineralization occurred in the Triassic. The Triassic suites have adakite-like character with high Sr/Y, and show no or minimal negative Eu anomalies, indicating early dominant amphibole with limited plagioclase fractionation. For the Triassic intrusions, the high zircon Eu/Eu* (0.67–0.89), Δ_FMQ (1.04 ± 0.53; where Δ_FMQ is the log fO₂ difference between the sample value and the fayalite-magnetite-quartz mineral buffer), hygrometer values (∼7.19 wt.% H₂O) and high whole-rock Fe₂O₃/FeO, Sr/Y, V/Sc and 10,000×(Eu/Eu*)/Y ratios together indicate the Triassic magmas were oxidized and hydrous. These contents and ratios of the Triassic suites are significantly higher than those of the Ordovician suites (Δ_FMQ = 0.74 ± 0.26, ∼5.90 wt.% H₂O), suggesting that the newly discovered Triassic magmas are more oxidized and hydrous, with high potential for porphyry copper mineralization. Based on the investigation of mineralization and the above results, we proposed that multiple superimposed mineralizations can help form a large-scale deposit and the southeastern segment is a favorable exploration area at Tongshan.

This study highlights a new by-product source for cobalt by recycling Paleoproterozoic Mn deposits. We present a geochemical modeling approach utilizing Principal Component Analysis (PCA) for available geochemical data of Paleoproterozoic manganese deposits found in Africa and Brazil, which exhibit anomalous cobalt contents (up to 1200 ppm) along with other metals such as copper, nickel, and vanadium. The PCA results for the correlation coefficient matrix of the Enrichment Factor (EF) values of major and trace elements from samples of eight Mn deposits found in Africa and Brazil (Kisenge-Kamata, Moanda, Nsuta in Africa, and Azul, Buritirama, Lagoa do Riacho, Morro da Mina, and Serra do Navio in Brazil) yielded a cumulative variance of 53.3% for PC1 (34%) and PC2 (19.3%). In PC1, the highest positive loadings correspond to the variables Mn_EF, Ni_EF, and Co_EF, while the highest negative loadings correspond to the variables Si_EF, Fe_EF, K_EF, Ti_EF, Cr_EF, and Zr_EF. PC2 exhibits the highest positive loadings for the variables Ca_EF, Mg_EF, and P_EF, while the highest negative loadings are for Cu_EF and V_EF. The biplot diagram representation showed that clusters of vectors Mn_EF, Ni_EF, Co_EF, V_EF, and Cu_EF influence samples of Mn-carbonate rock, Mn-carbonate–silicate rock, Mn-silicate rock, and Mn-carbonate-siliciclastic rock, all with high Co_EF values (up to 414). The cluster of vectors Ca_EF, Mg_EF, and P_EF significantly influence carbonate rock and dolomite marble, which have low Co_EF values (close to 0). The cluster of vectors Si_EF, Fe_EF, K_EF, Ti_EF, Cr_EF, and Zr_EF strongly influences siliciclastic rock, which exhibits low Co_EF values. On the other hand, the cluster of vectors Cu_EF and V_EF influences oxidized Mn ore, which exhibits Co_EF values of up to 108. The results reveal a dichotomy regarding the origin of cobalt and other metal enrichments in these deposits linked to the Mn redox cycle. This process involves the formation of Mn-oxyhydroxides with the adsorption of Co and other metals under oxic conditions, followed by the burial of these Mn oxides in an anoxic diagenetic environment, where microbial sulfate reduction leads to the nucleation of Mn-carbonates and the formation of metal-rich sulfides (Fe, Co, Ni, V). Additionally, detrital input and sulfide phases (e.g., framboidal pyrite) for the formation of Mn-rich siliciclastic rocks associated with Mn-carbonate rocks are evidenced by proxies Si_EF, Fe_EF, K_EF, Ti_EF, Cr_EF, and Zr_EF. This new exploration approach, supported by geochemical modeling through PCA, enhances our understanding of the genesis of these Paleoproterozoic manganese deposits and highlights a new route for cobalt exploration. In the increasing global demand for cobalt, particularly in applications involving electric vehicle batteries and energy storage, exploring these deposits emerges as an alternative source to produce these critical metals.

This study focuses on the assessment of ecosystem health (EH), ecosystem services (ES), and ecosystem risk (ER) in East Kolkata Wetland (EKW). A comprehensive framework on the EH, ES and ER has been developed using remote sesning and geo-spatial techniques for the year 2000, 2005, 2010, 2015, and 2020. The study also assessed ecosystem structure and fragmentation using landscape metrics calculated using fragstats, which showed a significant influence of land use and land cover (LULC) changes on the wetland’s ecological integrity. The study revealed that 6.86% of EKW fallen under a very low EH zone, while 20% was categorized as having very high EH. Spatio-temporal analysis of ES indicated that 30% of the area had very low ES value, with only 8% exhibiting very high ES. ER assessment revealed that 7% of the study area was highly ER, while 12% identified within a high ER zone, reflecting frequent LULC changes. The correlation analysis highlighted strong negative relationships between landscape deviation degree (LDD) and EH (−0.971), and between normalized difference water index (NDWI) and normalized difference vegetation index (NDVI) (−0.991). Additionally, landscape metrics such as the number of patches (NP) and the largest patch index (LPI) exhibited significant correlations, emphasizing the impact of fragmentation on EH and resilience. This comprehensive assessment underscores the importance of integrated approaches to monitor and manage wetland ecosystems, particularly in urban areas facing significant environmental stressors. The findings are crucial for informed decision-making and sustainable management of the wetland ecosystems, particularly in the cities of the global south.

The circular economy (CE) presents a promising approach to integrating industry with sustainability and circularity, which helps minimize ecological harm and preserve natural resources for future generations. This study focused on the roles of nuclear energy, renewables, and climate policies in advancing a CE. It examined the intentions of OECD countries regarding CE practices and the various factors influencing these intentions from 2000 to 2019. This study utilized second-generation panel data tools, such as slope homogeneity and stationarity tests, to assess cross-sectional dependence and heterogeneity in the panel dataset. The study employed the moment quantile regression (MM-QR) method to obtain regression estimates and analyze the conditional distribution across all quantiles. The findings indicated that the role of nuclear energy in promoting CE was negative across all quantiles. In contrast, renewable energy positively supports achieving CE in OECD countries. Climate policies assisted OECD countries in progressing toward CE in both the nuclear energy and renewable energy models. We conducted a robust check using a non-parametric panel Granger causality test, which confirmed the expected results for all other factors. The collaborative efforts for waste minimization ensure that nuclear energy systems are resilient, economically feasible, and environmentally sustainable.

Aboveground biomass (AGB) and belowground biomass (BGB) are key components of carbon storage, yet their responses to future climate changes remain poorly understood, particularly in China. Understanding these dynamics is essential for global carbon cycle modeling and ecosystem management. This study integrates field observations, machine learning, and multi-source remote sensing data to reconstruct the distributions of AGB and BGB in China from 2000 to 2020. Then CMIP6 was used to predict the distribution of China under three SSP scenarios (SSP1-1.9, SSP2-4.5, SSP5-8.5) from 2020 to 2100 to fill the existing knowledge gap. The predictive accuracy for AGB (R² = 0.85) was significantly higher than for BGB (R² = 0.48), likely due to the greater complexity of modeling belowground dynamics. NDVI (Normalized Difference Vegetation Index) and soil organic carbon density (SOC) were identified as the primary drivers of AGB and BGB changes. During 2000-2020, AGB in China remained stable at approximately 10.69 Pg C, while BGB was around 5.06 Pg C. Forest ecosystems contributed 88.52% of AGB and 43.83% of BGB. AGB showed a relatively slow annual increase, while BGB demonstrated a significant annual growth rate of approximately 37 Tg C yr^-1. Under the low-emission scenario, both AGB and BGB show fluctuations and steady growth, particularly in South China and the northwestern part of Northeast China. Under the moderate-emission scenario, AGB and BGB show significant declines and increases, respectively. In the high-emission scenario, both AGB and BGB decline significantly, particularly in the southwestern and central regions. These results provide valuable insights into ecosystem carbon dynamics under climate change, emphasizing the relatively low responsiveness of AGB and BGB to climatic variability, and offering guidance for sustainable land use and management strategies.

The Heilongjiang Complex in northeast China (NE China) separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean, as evidenced by a variety of oceanic basalt-derived blueschists. Understanding the closure history of the Mudanjiang Ocean is crucial to unravelling the tectonic transition from the final amalgamation of the Central Asian Orogenic Belt (CAOB) to the onset of the Paleo-Pacific subduction. In this study, we investigate epidote-ferroglaucophane (Ep-Fgl) and garnet-ferrobarroisite (Grt-Fbrs) schists from the Yilan area of the Heilongjiang Complex through petro-logical, mineralogical, thermodynamic modelling, whole-rock geochemical, and geochronological analy-ses. The Ep-Fgl schists preserve a peak assemblage of ferroglaucophane + epidote + chlorite + clinopyroxene + phengite + titanite with peak P-T conditions of 13.5-15.8 kbar and 458-495 °C. On the other hand, the Grt-Fbrs schists exhibit a peak assemblage of garnet + glaucophane/ferroglauco phane + lawsonite + chlorite + phengite + rutile ± clinopyroxene ± titanite, deriving peak P-T conditions of 16.4-18.3 kbar and 457-475 °C. Both types of schist record similar clockwise P-T paths, with three metamorphic stages: a peak epidote-to-lawsonite blueschist-facies stage, a post-peak decompression stage in the epidote amphibolite-facies, and a late greenschist-facies overprint stage. The Ep-Fgl schists display alkaline OIB-like geochemical affinities, while the Grt-Fbrs schists show tholeiitic MORB-like characteristics, suggesting that the protoliths represent fragments of the Mudanjiang oceanic crust. Magmatic zircon grains from Ep-Fgl schists yield protolith ages of 276 ± 1 Ma and 280 ± 1 Ma, whereas zircon of Grt-Fbrs schists document protolith ages of 249 ± 2 Ma and 248 ± 2 Ma, indicating that the Mudanjiang Ocean existed since at least the early Permian. Reconstruction of the metamorphic P-T evo-lution, combined with previous magmatic and metamorphic age data from rocks of the Heilongjiang Complex and of adjacent tectonic units suggests that the subduction and eventual closure of the Mudanjiang Ocean occurred between the late Triassic and middle Jurassic, driven by a regional stress regime shift caused by the westward subduction of the Paleo-Pacific Plate beneath Eurasia.

Highly evolved granite associated with pegmatite shells exhibits significant potential for rare metal min-eralization; however, the mechanisms through which these pegmatite shells contribute to magmatic evo-lution and rare metal enrichment remain poorly understood. The Late Jurassic Shihuiyao Nb-Ta-(Rb-Be- Li) deposit is one of the largest rare-metal deposits in the Southern Great Xing’an Range (SGXR), Northeast China. Exploratory trenches expose distinct layered zones from top to bottom: alternating microcline pegmatite and aplite layers (zone I), topaz lepidolite albite granite and lepidolite amazonite pegmatite (zone II), and muscovite albite granite (zone III). We conducted U-Pb dating of cassiterite, monazite, and Nb-Ta oxide, monazite Nd isotopes, and whole-rock and mineral geochemistry for the three zones. Multi-mineral U-Pb ages indicate that the three zones formed during the Late Jurassic- Early Cretaceous (147-142 Ma). Geochemical analyses of whole-rock, mica, and microcline suggest an evolutionary sequence from zone I to zone III, and finally to zone II. The Zr/Hf, Nb/Ta, Y/Ho, and K/Rb ratios combined with the rare earth element (REE) tetrad effects suggest higher degree of differentiation and fluid-melt interaction of the Shihuiyao leucogranite without a pegmatite shell compared to coeval barren granites from both Shihuiyao and the SGXR. A progressive increase in the degree of evolution is evident from the leucogranite without a pegmatite shell to the leucogranite with a discontinuous shell, and ultimately to the leucogranite with a continuous shell. The pegmatite shell acted as a geochemical barrier that facilitated the accumulation of Li and F in the underlying magma, which played a crucial role in lowering the solidus temperature of the granitic magma. This process prolonged the crystallization duration while reducing melt viscosity and density, thereby creating favorable conditions for magma dif-ferentiation and fluid-melt interaction. Rapid crystallization of the earlier water-and Be-rich melt led to the Be mineralization in the pegmatite shell. Moreover, the formation of this shell served as a barrier for Li mineralization in the underlying topaz lepidolite albite granite. This study enhances our understanding of the critical contribution of pegmatite shells to magmatic evolution and rare-metal mineralization.

The green energy transition relies heavily on critical metals, such as rare earth elements (REEs). However, their reserves are primarily focused in a few countries, such as China, which accounts for approximately 70% of global production. Hence, several countries are currently looking for alternative resources for REEs. Alternative REE resources in the supply chain include recycling of e-waste, industrial waste like red mud and phosphogypsum, coal ash, mine tailings, ocean floor sediments, and even certain types of sedimen-tary deposits like phosphorites where REEs are present in lower concentrations but at larger volumes compared to primary ore deposits which are becoming targets by REEs industry. Currently, several stud-ies are going on the development of eco-friendly REEs extraction technologies from phosphorite deposits. Consequently, advanced data analysis tools, such as Machine Learning (ML), are becoming increasingly important in mineral prospectivity and are rapidly gaining traction in the earth sciences. Phosphorite deposits are mainly used to manufacture fertilizers as these rocks are known for their significant phos-phorus content. Moreover, these formations are considered a prospective resource of REEs. The different types of phosphorite deposits such as continental, seamount, and ore deposits worldwide reported con-centrations of ∑REE upto 18,000 µg/g. Due to the augmented claim of REEs for various ultra-modern, and green technology applications that are required to switch over to a carbon-neutral environment, these phosphorite deposits have become an important target mostly because of their relatively higher content of REEs especially heavy rare earth elements (HREE). For example, Mississippian phosphorites reported ∑HREE 7,000 µg/g. To have a comprehensive understanding of the REEs potential of these phosphorite deposits which also include several Chinese phosphorite deposits, this study is undertaken to review the phosphorite deposits in the world and their REEs potential, in addition to some of the associated aspects such as applications and formation mechanisms for different types of phosphorite deposits such as igneous phosphate deposits, sedimentary phosphorite deposits, marine phosphorite deposits, cave phosphate deposits, and insular guano deposits. Other important aspects include their occurrences, types, geochemical characteristics, the REEs enrichment mechanisms, and various recovery methods adopted to recover REEs from different phosphorite deposits. The present review paper concludes that the recent studies highlight the global potential of phosphorite deposits to satisfy the increasing demand for REEs. Extracting REEs from phosphorite presents no significant technological or environmental difficul-ties, as long as radioactive elements are eliminated. In India, more comprehensive geological surveys, along with the advancement of new methods and evaluations, are required to locate phosphorite deposits with high concentrations of REEs.

The measurement of trace elements in Antarctic snow is crucial for understanding historical atmospheric geochemical changes and circulation patterns. However, studies on their spatial distributions remain limited, particularly those evaluating multiple metals across several snowpits, making interpretation challenging. This study investigates the distributions and sources of trace elements-including Cd, Ba, Pb, U, Bi, V, Mn, Fe, Cu, Zn, and As-across four snowpits in the Lambert Glacier Basin, East Antarctica. The trace elements exhibit site-, element-, and season-dependent variations, with higher concentrations observed at inland sites. In contrast, δ¹⁸O and ion concentrations decrease with increasing distance from the coast and elevation, underscoring the influence of marine emissions. Crustal sources primarily contributed to Ba, U, V, Mn, and Fe, while non-crustal sources predominantly contributed to Cd, Bi, Zn, Pb, Cu, and As. Positive matrix factorization (PMF) analysis indicates that trace element concentrations in Pits 2 and 3 are influenced by both crustal and non-crustal sources, while Pit 4 reflects a mixed-source influence. Pit 1 (coastal site) also indicates the mixed sources with influence of a highly dynamic marine climate and environment. The PMF results reveal similarities in emission sources and atmospheric transport patterns across the snowpits, facilitating a more comprehensive interpretation of longer ice core records. Overall, this study provides valuable insights into trace element distributions and enhances our understanding of past environmental and climatic conditions.

Extraterrestrial dust exhibits a wide range of textural, chemical and oxygen isotopic compositions due to the heterogeneity of their precursors and modification during atmospheric entry. Experimental heating provides an opportunity to investigate the relationship between thermal processing and micrometeorite composition for a known precursor material. We conducted experiments to simulate the atmospheric entry of micrometeorites (MMs) using controlled, short-duration (10-50 s) flash heating (400-1600 °C) of CI chondrite chips (<1500 lm) in atmospheric air (1 bar, 21% O₂) combined with microanal-ysis (textures, chemical and isotopic compositions) of the experimental products. The heated chips clo-sely resemble natural samples, with materials similar to unmelted MMs, partially melted (scoriaceous) MMs and fully melted cosmic spherules produced. We reproduced several key features such as dehydra-tion cracks, magnetite rims, volatile gas release, vesicle formation and coalescence, melting and quench cooling. Our parameter space allows for discriminating peak temperature and heating duration effects. Peak temperature is the first-order control on MM mineralogy, while heating duration controls vesicle coalescence and homogenization. When compared against previous heating experiments, our data demonstrates that CI chondrite dust is more thermally resistant, relative to CM chondrite dust, by approximately +200 °C. The 207 measurement of O-isotopes allows, for the first time, petrographic effects (such as volatile degassing and melting) to be correlated against bulk O-isotope evolution. Our results demonstrate findings applicable to CI chondrites and potentially to all fine-grained hydrated carbona-ceous chondrite dust grains: (1) O-isotope variations arising during sub-solidus heating are dominated by the release of water from phyllosilicates, forcing the residual MM composition towards its anhydrous precursor composition. (2) Oxygen isotope compositions undergo the most significant changes at supra-solidus temperatures. As previously demonstrated and now empirically confirmed, most of these changes are driven by a mass-dependent fractionation effect caused by evaporation, which shifts residual rock compositions toward heavier values. Mixing with atmospheric air alters compositions toward the terres-trial fractionation line. Notably, these two processes do not begin simultaneously. Our data indicate that at 1200 °C, isotopic evolution is dominated by evaporative mass loss. However, at higher temperatures (1400-1600 °C), both pronounced evaporation and mixing with atmospheric oxygen become active, resulting in a more complex isotopic signature. (3) The total change in Δ¹⁷O during heating up to 1600 °Cis < 3‰ and in most scenarios < 2‰.

The Cretaceous gold deposits along the margins of the North China Craton (NCC), which formed in a cra-ton destruction setting, display geological characteristics similar to traditional orogenic gold deposits typically associated with accretionary orogeny. These deposits, known as Jiaodong-type gold deposits, have attracted considerable attention. However, the lithospheric controls and formation mechanisms of these deposits remain unclear, as they cannot be fully explained by the supracrustal metamorphic genetic model commonly applied to classic orogenic gold deposits. In this study, the compiled S-Hg-Pb isotope ratios of gold deposits on different NCC margins display compatible variations to the Sr-Nd-Hg isotope ratios of mafic dikes spatial-temporally associated with the deposits. This implies that mantle lithosphere, metasomatized by variable proportions of oceanic and continental crust, was the source for both gold deposits and mafic dikes. Increase of oxygen fugacity and zircon εHf(t) from pre- to syn-gold granites suggests continuous basic magma underplating, which could induce concentrations of Au-rich sulfides and contribute additional Au to auriferous CO₂-rich fluids derived from metasomatized mantle lithosphere and basic magma. Localization of gold deposits was controlled by craton-margin sinistral shearing induced by clockwise rotation of the craton coincident with distal emplacement of metamorphic core complexes. Thus, the Cretaceous Jiaodong-type orogenic gold deposits were derived from fertilized mantle lithosphere through such crust-mantle processes within a lithosphere thinning background.