The application of three-dimensional (3D) point cloud parametric analyses on exposed rock surfaces, enabled by Light Detection and Ranging (LiDAR) technology, has gained significant popularity due to its efficiency and the high quality of data it provides. However, as research extends to address more regional and complex geological challenges, the demand for algorithms that are both robust and highly efficient in processing large datasets continues to grow. This study proposes an advanced rock joint identification algorithm leveraging artificial neural networks (ANNs), incorporating parallel computing and vectorization of high-performance computing. The algorithm utilizes point cloud attributes-specifically point normal and point curvatures-as input parameters for ANNs, which classify data into rock joints and non-rock joints. Subsequently, individual rock joints are extracted using the density-based spatial clustering of applications with noise (DBSCAN) technique. Principal component analysis (PCA) is subsequently employed to calculate their orientations. By fully utilizing the computational power of parallel computing and vectorization, the algorithm increases the running speed by 3-4 times, enabling the processing of large-scale datasets within seconds. This breakthrough maximizes computational efficiency while maintaining high accuracy (compared with manual measurement, the deviation of the automatic measurement is within 2°), making it an effective solution for large-scale rock joint detection challenges.

Back-arc basins are key sites for oceanic lithosphere formation and consumption at convergent plate boundaries, and their formation and subduction processes can be highly variable. The tectonic setting and evolution of the Meso-Tethys Shiquanhe-Jiali ophiolite sub-belt (SJO sub-belt) within Bangong-Nujiang Suture Zone (BNSZ), central Tibet, are disputed for the complex rock composition and ages. In this paper, we present geochronology, geochemistry and field observations on the Shiquanhe ophiolite, providing a representative ophiolite example in the western end of SJO. Based on investigation of the petrogenesis and tectonic setting of different rock types, combined with the U-Pb dating, we propose a two-stage subduction model for explaining the tectonic evolution of SJO as well as the wither away of a back-arc basin. Geochemical and geochronological data indicate that the ca. 183 Ma LAN (north of Lameila) gabbros formed in the forearc setting and represent the early-stage subduction of the Bangong Meso-Tethys. This subduction induced the back-arc spreading recorded in the ca. 170 Ma gabbros and lower pillow basalts of PL-SDN (Pagelizanong-Shiquanhe Dam Nan) ophiolitic fragments in the Shiquanhe ophiolite. The basaltic lavas overlying the lower basalts, represented by the ca. 168-164 Ma diabasic and boninite dikes have forearc characteristics, and they represent the back-arc basin subduction initiation at a late stage. This work thus recovered the multiple tectonic evolution of SJO sub-belt and emphasise the importance of the back-arc basin subduction in the evolution of ancient oceans.

The late Carboniferous to early Permian period is renowned for extensive coal formation and frequent paleowildfires. Nonetheless, the nature and distribution of these wildfires varied significantly over time. In an effort to elucidate the patterns of paleowildfires during the late Paleozoic Ice Age and to probe into the controlling mechanisms of paleowildfires under icehouse conditions, a comprehensive analysis was performed on coal samples from the Taiyuan and Shanxi formations within the Dacheng coalfield of Hebei Province, North China. The dataset was augmented with global inertinite data from the late Carboniferous to early Permian periods and was compared to paleowildfire patterns from the Pliocene to Holocene epochs. The results show that paleowildfires in the Dacheng coalfield of North China transitioned from moderate-scale, low-intensity surface fires to large-scale, relatively high-intensity ground fires. Globally, the distribution of paleowildfires shifted from Euramerica to Gondwana, Cathaysia, and Angara from 300 Ma to 290 Ma, accompanied by a corresponding increase in inertinite content. This spatial and temporal variation in wildfire activity appears to have been strongly influenced by paleoclimate and atmospheric conditions. At 300 Ma, cooler and wetter paleoclimate, coupled with relatively low atmospheric pO₂ levels, likely contributed to a reduced incidence of paleowildfires. In contrast, at 290 Ma, warmer paleoclimate, higher atmospheric pO₂ levels, and the flourishing mires in Gondwana, Cathaysia, and Angara were conducive to more intense paleowildfires. This pattern is further supported by the comparison to more recent icehouse periods. Similar to the late Carboniferous-early Permian period, wildfire activity increased from the Pliocene to the Holocene, highlighting the critical role of climatic conditions in driving wildfire proliferation under icehouse conditions. However, the Pleistocene to Holocene wildfires were less intense than those of the late Carboniferous-early Permian, suggesting that atmospheric oxygen concentrations played a key role in modulating the evolution of the fire systems over geological timescales. These findings underscore the complex interplay between climate, atmospheric composition, and vegetation in shaping wildfire dynamics across Earth's history.

While the significant role of technological innovation in promoting renewable energy has been extensively explored in the literature, limited attention has been paid to the impact of energy patents, particularly clean energy patents and fossil fuel patents. This study pioneers an investigation into the effects of energy patents and energy prices on renewable energy consumption. The study utilizes data from 2000Q1 to 2023Q4 and, due to the nonlinear nature of the series, applies wavelet quantile-based methods. Specifically, it introduces the wavelet quantile cointegration approach to evaluate cointegration across different quantiles and time horizons, along with the wavelet quantile-on-quantile regression method. The results confirm cointegration across different periods and quantiles, highlighting the significant relationships between energy patents, economic factors, and renewable energy consumption. Furthermore, we found that fossil energy patents negatively affect renewable energy consumption, while clean energy patents have a similar but weaker effect, especially in the short term. In addition, higher energy prices promote renewable energy adoption while economic growth positively influences renewable energy consumption, particularly in the short term. The study formulates specific policies based on these findings.

This research examines the hard-rock aquifer system within the Nagavathi River Basin (NRB) South India, by evaluating seasonal fluctuations in groundwater composition during the pre-monsoon (PRM) and post-monsoon (POM) periods. Seasonal variations significantly influence the groundwater quality, particularly fluoride (F^—) concentrations, which can fluctuate due to changes in recharge, evaporation, and anthropogenic activities. This study assesses the dynamics of F^— levels in PRM and POM seasons, and identifies elevated health risks using USEPA guidelines and Monte Carlo Simulations (MCS). Groundwater in the study area exhibits alkaline pH, with NaCl and Ca-Na-HCO₃ facies increasing in the POM season due to intensified ion exchange and rock-water interactions, as indicated in Piper and Gibb's diagrams. Correlation and dendrogram analyses indicate that F^— contamination is from geogenic and anthropogenic sources. F^— levels exceed the WHO limit (1.5 mg/L) in 51 PRM and 28 POM samples, affecting 371.74 km² and 203.05 km², respectively. Geochemical processes, including mineral weathering, cation exchange, evaporation, and dilution, are identified through CAI I & II. Health risk assessments reveal that HQ values >1 in 78% of children, 73% of teens, and 68% of adults during PRM, decreasing to 45%, 40%, and 38%, respectively, in POM. MCS show maximum HQ values of 5.67 (PRM) and 4.73 (POM) in children, with all age groups facing significant risks from fluoride ingestion. Managed Aquifer Recharge (MAR) is recommended in this study to minimize F^— contamination, ensuring safe drinking water for the community.

The Beijing-Tianjin-Hebei Plain is among the regions in China that feature the largest scale and the fastest growth in medium and deep geothermal heating. Based on tests of 82 geothermal fluid samples from 7 geothermal fields in Hebei Province, 2 geothermal fields in Henan Province, and 2 geothermal fields in Shandong Province, and combined with previous studies on the chemical characteristics of karst geothermal water in Beijing and Tianjin, this paper systematically analyzes the migration characteristics of geothermal fluids in karst geothermal reservoirs within the Beijing-Tianjin-Hebei Plain. The hydrochemical characteristics of karst geothermal water in the research areas exhibit certain differences. The geothermal water in Hebei is more mature than that in its neighboring provinces. The distribution of total dissolved solids (TDS) and strontium elements in the area is characterized by being low in the north and south and high in the middle, suggesting that the overall flow direction of geothermal fluid is from the north and south towards the middle. Combined with the groundwater flow field and the changing trend of the hydrochemical characteristics of geothermal wells along the geological section, a geothermal water migration model has been established. The geothermal fluids originating from Taihang Mountain, Yanshan Mountain, and Western Shandong Mountain enter the basin and continue to migrate towards the central part of the basin along water-conducting faults. However, the migration characteristics of geothermal fluids with the same supply direction are not identical. The geothermal fluids from Taihang Mountain are cut off by the Niudong Fault in the north and terminate in the central uplift belt of the Jizhong Depression, while in the south, they enter the east of the Jizhong Depression relatively quickly along the Hengshui Conversion Belt. The geothermal fluids from Yanshan Mountain migrate into the basin along the Cangdong Fault, yet this fault also disrupts the hydraulic connection between the tectonic units. Considering the effective dynamic conditions, it is recommended to further expand the scale of the scientific development and utilization of geothermal energy in the geothermal water catchment areas around Xiongxian County and southwest Cangzhou City.

Agriculture is a major contributor to the global economy, accounting for approximately 70% of the freshwater use, which cause significant stress on aquifers in intensively irrigated regions. This stress often leads to the decline in both the quantity and quality of groundwater resources. This study is focused on an intensively irrigated region of Northern India to investigate the sources and mechanism of groundwater recharge using a novel integrated approach combining isotope hydrology, Artificial Neural Network (ANN), and hydrogeochemical models. The study identifies several key sources of groundwater recharge, including natural precipitation, river infiltration, Irrigation Return Flow (IRF), and recharge from canals. Some groundwater samples exhibit mixing from various sources. Groundwater recharge from IRF is found to be isotopically enriched due to evaporation and characterized by high Cl^-. Stable isotope modeling of evaporative enrichment in irrigated water helped to differentiate the IRF during various cultivation periods (Kharif and Rabi) and deduce the climatic conditions prevailed during the time of recharge. The model quantified that 29% of the irrigated water is lost due to evaporation during the Kharif period and 20% during the Rabi period, reflecting the seasonal variations in IRF contribution to the groundwater. The ANN model, trained with isotope hydrogeochemical data, effectively captures the complex interrelationships between various recharge sources, providing a robust framework for understanding the groundwater dynamics in the study area. A conceptual model was developed to visualize the spatial and temporal distribution of recharge sources, highlighting how seasonal irrigation practices influence the groundwater. The integration of isotope hydrology with ANN methodologies proved to be effective in elucidating the multiple sources and processes of groundwater recharge, offering insights into the sustainability of aquifer systems in intensively irrigated regions. These findings are critical for developing data-driven groundwater management strategies that can adapt to future challenges, including climate change, shifting land use patterns, and evolving agricultural demands. The results have significant implications for policymakers and water resource managers seeking to ensure sustainable groundwater use in water-scarce regions.

Large-scale Danian-age (post-K/Pg boundary) Deccan magmatism is well known from the Mumbai metropolitan area, located in the structurally complex Panvel flexure zone along the western Indian rifted continental margin. This compositionally diverse late-Deccan magmatic suite contains subaerial tholeiitic lavas and dykes typical of the main Deccan province, with many features atypical of the Deccan, such as spilitic pillow lavas, "intertrappean" sediments (often containing considerable volcanic ash), rhyolitic lavas and tuffs, gabbro-granophyre intrusions, and trachyte intrusions containing alkali basalt enclaves. Most of these units, previously dated at 62.5 Ma to 61 Ma, are contemporaneous with or slightly postdate the 62.5 Ma India-Seychelles continental breakup and Panvel flexure formation. In the Dongri-Uttan area, two samples of a >50-m-thick, columnar-jointed rhyolite from the Darkhan Quarry and from a section behind the current Uttan Sagari Police Station have previously been dated at 62.6 ± 0.6 Ma and 62.9 ± 0.2 Ma (⁴⁰Ar/³⁹Ar, 2σ errors). New exposures reveal that these two statistically indistinguishable ⁴⁰Ar/³⁹Ar ages correspond to two distinct rhyolite units, separated by well-bedded silicic ash. The columnar rhyolites are microcrystalline, composed of quartz and alkali feldspar, with rare small (1-2 mm), altered feldspar phenocrysts, and no recognisable relict vitroclasts. Given the westerly structural dip, most of their lateral extent is submerged under the Arabian Sea, and we consider them to be possible flood rhyolite lavas. We interpret the ash beds, composed of pumice clasts and glass shards, as a low-grade (nonwelded) vitric ash, derived from a possibly distal Plinian eruption and deposited by fallout. The lavas and ash are peraluminous rhyolites. The lavas are Sr-Ba-poor and Rb-Zr-Nb-rich, and show ";seagull-shaped" rare earth element patterns with deep negative europium anomalies. These crystal-poor lavas are "hot-dry-reduced" rhyolites typical of intraplate, continental rift and rifted margin settings. The very different high-field strength element contents of the lavas and the ash indicate compositionally distinct magma batches. The 62.5 Ma Dongri-Uttan sequence provides clear evidence for rapid silicic eruptions of effusive and explosive nature, alternating with each other and sourced from distinct magma chambers and eruptive vents. A newly identified, highly feldspar-phyric trachyte intrusion marks the last phase of magmatic activity in the area, corresponding with late-stage trachyte-syenite intrusions exposed in coastal western India and the Seychelles, and shows that the Mumbai rhyolites and trachytes form a compositional continuum.

Climate change is significantly influenced by both clouds and Earth's surface temperature (EST). While numerous studies have investigated clouds and EST separately, the extent of clouds' impact on EST remains unclear. Based on the inspiration and limitation of cloud radiative effect (CRE), this study provides a pioneering attempt to propose a novel indicator, cloud radiative effect on surface temperature (CREST), aiming to quantify how clouds affect EST globally while also analyzing the physical mechanism. Using reanalysis and remotely sensed data, a phased machine learning scheme in combination of surface energy balance theory is proposed to estimate EST under all-sky and hypothetical clear-sky conditions in stages, thereby estimating the newly defined CREST by subtracting the hypothetical clear-sky EST from the all-sky EST. The inter-annual experiments reveal the significant spatial heterogeneity in CREST across land, ocean, and ice/snow regions. As a global offset of the heterogeneity, clouds exhibit a net warming effect on global surface temperature on an annual scale (e.g., 0.26 K in 1981), despite their ability to block sunlight. However, the net warming effect has gradually weakened to nearly zero over the past four decades (e.g., only 0.06 K in 2021), and it's even possible to transform into a cooling effect, which might be good news for mitigating the global warming.

Small shelly fossils (SSFs) have long been recognized as important to the studies of both metazoan evolution and the onset of biomineralization during the Cambrian radiation. The marked decline in the occurrence, diversity and abundance of SSFs in the middle to late Cambrian, when compared with the early Cambrian, has often been regarded as a result of the closure of a phosphatization window. Despite this, there have been numerous and consistent reports of SSFs from the middle Cambrian and younger deposits. To identify possible factors influencing SSF preservation, five microfacies including bioclastic limestone, flat-pebble conglomerates with bioclasts, hummocky cross-stratified grainstone with bioclasts, bioclastic grainstone in hardgrounds and glauconite bioclastic wackstone-packstone, from Cambrian Series 2 to Miaolingian in North China are compared to assess how differences in lithology impact the preservation potential of SSFs. Our results, based on 35,161 SSF specimens from deposits across six sections, suggest that there are still abundant and diverse SSFs in the middle Cambrian of North China preserved in ways not exclusively reliant on the presence of phosphate and that SSF preservation can be linked to the differences in microfacies in the early to middle Cambrian of North China.

The spatial distribution of overburden layer thickness (OLT) is crucial for landslide susceptibility prediction and slope stability analysis. Due to OLT spatial heterogeneity in hillslope regions, combined with the difficulty and time consumption of OLT sample collection, accurately predicting OLT distribution remains a challenging. To address this, a novel framework has been developed. First, OLT samples are collected through field surveys, remote sensing, and geological drilling. Next, the heterogeneity of OLT's spatial distribution is analyzed using the probability distribution of OLT samples and their horizontal and vertical distributions. The OLT samples are categorized and the small sample categories are expanded using the synthetic minority over-sampling technique (SMOTE). The slope position is selected as a key conditioning factor. Subsequently, 16 conditioning factors are applied to construct OLT prediction model using the random forest regression algorithm. Weights are assigned to each OLT sample category to balance the uneven distribution of sample sizes. Finally, the Pearson correlation coefficient, mean absolute error (MAE), root mean square error (RMSE), and Lin's concordance correlation coefficient (Lin's CCC) are employed to validate the OLT prediction results. The Huangtan town serves as the case study. Results show: (1) heterogeneity analysis, SMOTE-based OLT sample expansion strategy and slope position selection can significantly mitigate the effect of spatial heterogeneity on OLT prediction. (2) The Pearson correlation coefficient, RMSE, MAE and Lin's CCC values are 0.84, 1.173, 1.378 and 0.804, respectively, indicating excellent prediction performance. This research provides an effective solution for predicting OLT distribution in hillslope regions.

The mechanical properties of minerals in planetary materials are not only interesting from a fundamental point of view but also critical to the development of future space missions. Here we present nanoindentation experiments to evaluate the hardness and reduced elastic modulus of olivine, (Mg, Fe)₂SiO₄, in meteorite NWA 12008, a lunar basalt. Our experiments suggest that the olivine grains in this lunaite are softer and more elastic than their terrestrial counterparts. Also, we have performed synchrotron-based high-pressure X-ray diffraction (HP-XRD) measurements to probe the compressibility properties of olivine in this meteorite and, for comparison purposes, of three ordinary chondrites. The HP-XRD results suggest that the axial compressibility of the orthorhombic b lattice parameter of olivine relative to terrestrial olivine is higher in NWA 12008 and also in the highly-shocked Chelyabinsk meteorite. The origin of the observed differences is discussed. A simple model combining the results of both our nanoindentation and HP-XRD measurements allows us to describe the contribution of macroscopic and chemical-bond related effects, both of which are necessary to reproduce the observed elastic modulus softening. Such joint analysis of the mechanical and elastic properties of meteorites and returned samples opens up a new avenue for characterizing these highly interesting materials.

Subducting slabs transport carbon to deep mantle depths and release it into the overlying mantle wedge and lithospheric mantle through multiple mechanisms, including mechanical removal via diapirism, metamorphic decarbonization, carbonate dissolution and parting melting. Identifying the dominant carbon recycling mechanism responsible for carbonation of subcontinental lithospheric mantle (SCLM) remains challenging, yet it is critical for understanding the genesis of post-collisional carbonatites and associated rare earth element deposits. To address this issue, we investigate the Li isotopic systematics of typical post-collisional carbonatite-alkalic complexes from Mianning-Dechang (MD), Southeast Tibet. Our results show that the less-evolved magmas (lamprophyres) have mantle-like or slightly lower δ⁷Li values (0.3‰-3.6‰) with limited variability, contrasting sharply with the wider δ⁷Li range observed in associated carbonatites and syenites. We interpret this dichotomy as reflecting distinct processes: while the variable and anomalous δ⁷Li values in differentiated rocks (carbonatites and syenites) were caused by late-stage magmatic-hydrothermal processes (including biotite fractionation, fluid exsolution and hydrothermal alteration), the lamprophyres retain the primary Li isotopic signature of their mantle source. Together with their arc-like trace element and EM1-EM2-type Sr-Nd-Pb isotopic signatures, such mantle-like or slightly lower δ⁷Li values of the lamprophyres preclude carbon derivation from high-δ⁷Li reservoirs (altered oceanic crust, serpentinites) and recycling of sedimentary carbon through metamorphic decarbonization or dissolution. Instead, these features indicate that the carbon was predominantly transported into the mantle source via partial melting of subducted carbonate-bearing sediments. This study demonstrates that Li isotopes can serve as a tracer for identifying the mechanism of carbon recycling in collision zones.

Iron oxide-copper-gold (IOCG) deposits encompass a diverse set of mineralization styles, leading to outstanding questions about how different alteration facies are related across a single ore-producing system and the overarching mechanisms of ore genesis. This study investigates the age and characteristics of mineralization at the La Farola deposit, a hematite-dominated IOCG deposit located at the southern margin of the Candelaria-Punta del Cobre IOCG district of northern Chile. Two lithologically-controlled ore bodies occur along the WSW-ENE striking, ~18° NNW-dipping contact between the Lower Cretaceous Chañarcillo Group and Punta del Cobre Formation. Syn-mineralization N-S to NNW-SSE striking sinistral strike-slip faults likely acted as fluid pathways. Distinct mineral assemblages include an early Na-Ca assemblage (albite-scapolite) overprinted by skarnoid garnet with minor pyroxene, Ca-Fe (magnetite-actinolite), and K-Fe (magnetite-k-feldspar-biotite and minor sulfides) assemblages. The main sulfide mineralization (chalcopyrite-pyrite with minor bornite) is associated with specular hematite-white mica-K-feldspar-calcite and overprints all previous assemblages. The presence of hematite as the dominant Fe-oxide phase associated with Cu mineralization is characteristic of lower-temperature IOCG deposits, and may be a result of La Farola's stratigraphic position <700 m higher than other deposits in the district. New U-Pb ages of 115.7 ± 1.2 Ma for garnet and Re-Os ages of ~113-114 Ma for sulfides indicate mineralization occurred within a 3-million-year timeframe. These findings confirm hematite-dominant mineralization at La Farola was coeval with IOCG mineralization across the district. This research contributes to understanding IOCG systems and their formation mechanisms, highlighting the control local geological structures and alteration processes has on the diversity of mineralization types associated with a single IOCG system.

The stability of reservoir bank slopes during the impoundment period has become a critical issue in the construction and operation of large-scale hydropower projects. A predictive and early warning method for reservoir bank slopes is proposed, based on slip resistance stability evolution analysis. Using a refined three-dimensional numerical calculation model of the bank slope, the creep damage model is employed for simulation and analysis, enabling the derivation of stress field and strain field evolution from bank slope excavation to the long-term impoundment period. Subsequently, for the stress field of the bank slope at any given moment, the safety factors of the sliding blocks are determined by using the multigrid method and vector sum method. Accordingly, the evolutionary law of the sliding safety factor for the bank slope can be derived. By integrating the long-term stability evolution trend of the slope with specific engineering practices, the safety factors for graded warning can be determined. Based on the time correspondence, the graded warning moment and the deformation warning index for slope measurement points can be determined. In this study, the proposed method is applied to the left bank slope of the Jinping I Hydropower Station. The results indicate that from excavation to June 2022, the left bank slope exhibits a strong correlation with excavation elevation and the number of reservoir water cycles. The initial, maximum, and minimum safety factors are 2.01, 3.07, and 1.58, respectively. The deep fracture SL_44-1 serves as the primary stress-bearing slip surface of the left bank slope, while the safety margin of the fault f_42-9 and lamprophyre X is slightly insufficient. Based on the long-term stability evolution trend of the slope and in accordance with relevant standards, the safety factors for graded warning indicators—K_w1, K_w2, K_w3, and K_w4— are determined as 1.350, 1.325, 1.300, and 1.275, respectively. Correspondingly, the estimated warning times are 12/30/2066, 12/30/2084, and 12/30/2120. Accordingly, the deformation graded warning indexes for slope measurement points are established.

The Late Paleozoic marked Earth’s most recent icehouse-greenhouse transition, providing valuable insights into future climate and environmental changes. Although the aridification of the North China Craton (NCC) during the Late Paleozoic is well established, its pattern and causes remain unclear. Here, we identify four aridification intervals from the late Gzhelian to Lopingian by analyzing continuous records of elemental climate proxies (MgO/CaO, Sr/Cu), a volcanism proxy (Hg/TOC), and spore-pollen assemblages. Interval I (~303-295 Ma), during which the NCC was located at low paleolatitudes, was characterized by humid conditions and a predominance of ferns, associated with weak volcanism. Interval II (~295-286 Ma) was subhumid, with increasing gymnosperm presence, and significant climate fluctuations linked to volcanism. CO₂ emissions from the Tarim LIP and Panjal Traps drove aridification from the late Asselian to late Artinskian, contributing to the decline of the Late Paleozoic Ice Age. As a result, aridification in the NCC lagged behind that of Pangea. Interval III (~286-280.98 Ma) marked the transition to subarid conditions and the onset of dominance by gymnosperms, associated with a rapid northward drift of the NCC and an increase in atmospheric ρCO₂. Interval IV (~259.51-251.902 Ma), separated from the underlying Interval III by a major regional unconformity (~280.98-259.51), coincided with global aridification and intensified volcanism. These findings highlight the significant influences of both tectonic plate motion and volcanism on the climate evolution of the NCC, with shifts in the dominant controlling factors through time. This study provides new insights into the distinct trajectories of global and regional climate dynamics.

The opening of the Central South Atlantic and the consequent formation of the eastern Brazilian continental margin was marked by a complex history of mafic magmatism, carbonate sedimentation, and deposition of a thick salt layer. The carbonates underlying the salt layer (pre-salt carbonates) were formed in restricted lacustrine basins. Here, the timing and fluid sources of deposition, diagenetic, and hydrothermal alterations of the pre-salt carbonate rocks are defined through in-situ U-Pb dating, ⁸⁷Sr/⁸⁶Sr, and trace element analyses of samples from the Santos Basin. The very alkaline nature of the Aptian lake(s) produced characteristically unique and widely distributed carbonate rocks such as Mg-clays with calcite spherulite and calcite crystal shrub limestones transitioning laterally and vertically into travertines formed by hydrothermal pulses during basin evolution. Hydrothermalism caused extensive replacement, dissolution, and calcite cementation. REE+Y PAAS-normalised patterns and ⁸⁷Sr/⁸⁶Sr ratios indicate that deposition/eo-diagenesis of the primary carbonates occurred in a lacustrine environment primarily controlled by evaporation, pH, and continental water source, with 2%-10% hydrothermal fluid input. Trace elements and Sr-isotope of travertines and burial diagenetic phases show that they are produced from a hot mixture of mafic/mantle-derived fluids and dissolution/alteration of older carbonate formations. U-Pb dating indicates that carbonate deposition occurred between 124.8 ± 2.6 Ma and 120.0 ± 1.6 Ma, earlier than previously proposed, followed closely by the circulation of hydrothermal fluids. Replacement and cementation ages range from 120.5 ± 2.4 Ma to 80.4 ± 2.4 Ma.

In the context of urbanization, air pollution has emerged as a significant environmental challenge. A thorough understanding of their transport pathways, especially at a national scale, is essential for environmental protection and policy-making. However, it remains partially elusive due to the constraints of available data and analytical methods. This study proposed a data-driven spatiotemporal correlation analysis method employing the Dynamic Time Warping (DTW). We represented the first comprehensive attempt to chart the long-term and nationwide transport pathways of PM_2.5 utilizing an extensive dataset spanning from 2000 to 2021 across China, which is crucial for understanding long-term air pollution trends. Compared with traditional chemical transport models (CTMs), this data-driven method can generate transport pathways of PM_2.5 without requiring extensive meteorological or emission data, and suggesting fundamentally consistent spatial distribution and trends. Our analysis reveals that China's transport pathways are notably pronounced in the Northwest (34% of the total pathways in China), Southwest (22%), and North (21%) regions, with less significant pathways in the Northeast (10%) region and isolated occurrences elsewhere. Additionally, a notable decrease in the number of China's PM_2.5 transport pathways, similar to annual average concentrations, was observed after 2013, aligning with stricter environmental regulations. Furthermore, we have demonstrated the feasibility of applying our method to the transport pathways of other gaseous pollutants. The approach is effective in detecting and quantifying air pollutants' transport pathways, even in regions like the Northwest with limited monitoring infrastructure, which may aid in environmental decision-making. The study will notably improve the current understanding of air pollutants' transport process, providing a new perspective for studying the large-scale spatiotemporal correlations.

This study advances the DRASTIC groundwater vulnerability assessment framework by integrating a multi-hazard groundwater index (MHGI) to account for the dynamic impacts of diverse anthropogenic activities and natural factors on both groundwater quality and quantity. Incorporating factors such as population growth, agricultural practices, and groundwater extraction enhances the framework's ability to capture multi-dimensional, spatiotemporal changes in groundwater vulnerability. Additional improvements include refined weighting and rating scales for thematic layers based on available observational data, and the inclusion of distributed recharge. We demonstrate the practical utility of this dynamic DRASTIC-based framework through its application to the agro-urban regions of the Irrigated Indus Basin, a major groundwater-dependent agricultural area in South Asia. Results indicate that between 2005 and 2020, 54% of the study area became highly vulnerable to pollution. The MHGI revealed a 13% decline in potential groundwater storage and a 25% increase in groundwater-stressed zones, driven primarily by population growth and intensive agriculture. Groundwater vulnerability based on both groundwater quality and quantity dimensions showed a 19% decline in areas of low to very low vulnerability and a 6% reduction in medium vulnerability zones by 2020. Sensitivity analyses indicated that groundwater vulnerability in the region is most influenced by groundwater recharge (42%) and renewable groundwater stress (38%). Validation with in-situ data yielded area under the curve values of 0.71 for groundwater quality vulnerability and 0.63 for MHGI. The framework provides valuable insights to guide sustainable groundwater management, safeguarding both environmental integrity and human well-being.

Fluids generated from the source rocks containing various kerogen types at different thermal maturity stages control diagenetic processes and reservoir quality in adjacent sandstone reservoirs. This study focuses on the carbonate cements in the sandstones of the Lower Jurassic Yangxia Formation and the Ahe Formation in the Tarim Basin. The δ¹⁸O, δ¹³C, and ⁸⁷Sr/⁸⁶Sr data indicate that low temperature ferroan calcite and manganoan calcite-characterized by strongly negative δ¹³C values and enrichment in light rare earth elements (LREEs)-record CO₂ released during the thermal degradation of organic matter predominantly composed of Type III kerogen in coal bearing source rocks and of Type II kerogen in mudstone source rocks, respectively. High temperature ferroan calcite and manganoan calcite, which exhibit similarly strongly negative δ¹³C values and enrichment in middle rare earth elements (MREEs), record organic acids and CO₂ produced during the thermal decarboxylation of these same source rocks. The diagenetic fluid evolution sequence comprises early stage CO₂ from thermal degradation of both coal bearing and mudstone source rocks; mid stage organic acids and CO₂ from thermal decarboxylation of coal bearing source rocks; and late stage organic acids and CO₂ from thermal decarboxylation of mudstone source rocks. Fluids generated during the thermal degradation of mudstone and coal bearing source rocks precipitated extensive calcite cements, leading to reservoir densification. Clumped isotope thermometry indicates that the primary generation periods of late stage mudstone derived fluids coincided with the formation of effective fractures. Feldspar dissolution along these fractures produced an interconnected network of fractures and dissolution pores, significantly enhancing reservoir quality in the Ahe Formation.

Copper extraction from chalcopyrite is challenging, because acid dissolution is slow, occurring incongruently via a complex three-step reaction mechanism. Silver has been known to catalyse copper extraction from chalcopyrite since the 1970's; yet the mechanism remains controversial. Microcharacterisation of experimental products obtained under optimal leaching conditions (50-150μm chalcopyrite grains in ferric/ferrous-sulfate solution with a redox potential around 500 mV vs. Ag/AgCl, approximately 1ppm Ag; [Ag] 6.4×10^-6 mol/L; 70℃; 4 days) highlights the heterogeneity of the reaction: μm-thick layers of a porous copper-sulfide with variable composition formed both in cracks within, and on the surface of the chalcopyrite grains. There is no evidence for formation of Ag-rich phases (Ag₂S_(s), Ag⁰_(s)). The fundamental three-step reaction mechanism remains the same with or without added silver; silver merely accelerates the initial dissolution step.

An integrated model for the catalytic effect of silver is proposed that incorporates recent advances in the reactivity of sulfide minerals. The initial reaction follows a 'Fluid-Induced Solid State Diffusion Mechanism', where diffusion of Fe in the chalcopyrite lattice is driven towards the surface by its rapid removal into solution, resulting in a Fe-deficient surface layer. The large Ag⁺ ion, relative to Cu⁺/Fe³⁺, diffuses into this Fe-deficient surface layer and accelerates chalcopyrite dissolution in the subsequent step, whereby chalcopyrite is replaced by copper sulfides via an interface coupled dissolution reprecipitation reaction as a consequence of the sulfide-rich micro-environment at the mineral surface. Effective Ag⁺ recycling is key to the catalytic effect of silver, and occurs as a result of the strong affinity of Ag⁺ for bisulfide ligands accumulating at the surface of dissolving chalcopyrite.

The architecture and geodynamics of intracontinental orogens remain a fundamental geological challenge. The Xing’an-Mongolia intracontinental orogenic belt (XMIOB), superimposed on the eastern Central Asian Orogenic Belt (CAOB), provides key insights into intracontinental orogenic belt dynamics. However, its architecture, deformation patterns, and geodynamic processes are poorly understood. This study integrates geological mapping, structural analysis, EBSD quartz c-axis fabrics, seismic reflection interpretation, and zircon U-Pb geochronology to unravel the XMIOB’s tectonic evolution and compare it with global intracontinental orogenic belts. Our findings reveal that the XMIOB is shaped by alternating fold-thrust belts and metamorphic zones, dominantly controlled by the inversion of pre-existing extensional structures. EBSD analysis indicates mid-temperature (400 °C - 500 °C) ductile deformation in the deep crust, while seismic profiles highlight structural decoupling driven by a décollement zone. Integrated crustal thickness reconstructions from zircon Eu/Eu* ratios delineate three tectonic stages: Late Carboniferous-Permian asthenospheric upwelling induced crustal thinning from ∼50 km to ∼35 km, forming lithospheric weak zones with Buchan-type metamorphism and bimodal magmatism; Late Permian-Middle Triassic mantle subduction triggered compressional thickening (∼55 km), fold-thrust belt formation, and tectonic inversion of early extensional faults, exposing metamorphic zones; from the Middle Triassic continued mantle subduction and deep-crustal decoupling drove large-scale lateral extrusion and dextral shear, reshaping the XMIOB architecture. Comparisons with global intracontinental orogenic belts highlight two key traits of intracontinental orogenic belt evolution: pre-orogenic lithospheric thinning generates inherited weak zones that localize subsequent deformation; inherited extensional features dictate the final architecture, producing the systematic alternation of metamorphic zones and fold-thrust belts.

Subduction initiation is a critical part of the plate tectonic system, but its geodynamic process is still poorly understood due to the lack of well-preserved geological records. Based on new zircon U-Pb-Hf isotopic and whole-rock geochemical data, we report the first discovery of a latest Cambrian-Early Ordovician forearc-arc rock sequence in the Eastern Alps. This sequence includes granitic gneisses, amphibolites, and amphibole plagiogneisses from the ophiolitic Speik Complex and Gleinalpe Complex. These rocks exhibit geochemical affinities with typical oceanic plagiogranites, forearc basalts (FABs), and island arc basalts, respectively. The latest Cambrian plagiogranitic protoliths (491 ± 2 Ma) are shearing-type plagiogranites that were formed in the tectonic setting of forearc spreading. The latest Cambrian FABs (496-489 Ma) have similar geochemical compositions and positive ε_Hf(t) values (+2.5 to + 14.9) to the depleted mid-ocean ridge basalts. However, they show depletion in high field strength elements (HFSEs; e.g., Nb, Ta, and Zr) and have relatively low Ti/V ratios. These features suggest that they were derived from a depleted mantle source modified by subducting slab-released components in a forearc environment. The Early Ordovician basaltic protoliths (476-472 Ma) of amphibole plagiogneisses show enrichment in large ion lithophile elements and depletion in HFSEs (e.g. Nb, Ta, Zr, and Hf), implying a mature island arc environment. These metaigneous rocks, along with the coeval boninite-like high-Mg amphibolites near the study area, form a typical rock sequence resembling that of the Izu-Bonin-Mariana (IBM) arc system. The Speik and Gleinalpe complexes document a complete magmatic evolution from subduction initiation to mature arc development within the West Proto-Tethys Ocean. Integrating our new data with published work, we reconstruct the late Ediacaran-early Paleozoic tectonic evolution of the northern Gondwana. During the late Ediacaran-early Cambrian, the rollback of the West Proto-Tethys oceanic plate triggered the separation of the Wechsel-Silvretta-Gleinalpe continental arc from the northern Gondwana. This process led to the formation of the Speik back-arc oceanic basin, a southwestern branch of the West Proto-Tethys Ocean. In the latest Cambrian-Early Ordovician, subduction initiation occurred in the Speik Ocean, which subsequently developed into an intra-oceanic arc system. During the Early Devonian, the Speik Ocean closed and the Wechsel-Silvretta-Gleinalpe continental arc reattached to the Gondwana, as evidenced by the metamorphic event at ca. 400 Ma.

Permafrost, a critical component of Earth's climate system, is increasingly subject to abrupt thaw events, which jeopardize infrastructure, reshape landforms, alter hydrological regimes, and disrupt ecosystems, thereby posing substantial threats to global sustainability. However, the underlying mechanisms that trigger these abrupt transitions remain incompletely understood. Here, we present decade-long in-situ observations from HRQ1, a marginal permafrost site in the Headwater Area of the Yellow River, northeastern Qinghai-Xizang Plateau. These data reveal the formation and growth of a talik, indicative of a permafrost tipping point. Absent before 2017, the talik subsequently formed and progressively deepened, extending to the maximum observation depth of 300 cm by 2024. The transition from perennially frozen to thawed conditions was accompanied by a substantial increase in mean annual soil temperature (MAST) throughout the entire soil profile. From 2015 to 2023, MAST in the upper 200 cm rose from sub-zero (-0.30 to -0.49 ℃) to consistently above 0 ℃ (0.07 to 1.08 ℃). Concurrently, maximum daily soil temperatures in deeper layers (200-300 cm) became positive, indicating thaw propagation into the relict permafrost. This warming coincided with a marked increase in unfrozen soil moisture, particularly within the expanding talik. The rapid, non-linear deepening of the talik, far exceeding rates attributable to conductive heat transfer alone, was driven by a strong convective mechanism (Rayleigh-Darcy instability). This advective process was triggered when the soil profile became fully saturated, a condition resulting from the convergence of intensified rainfall and enhanced water retention linked to decadal vegetation greening. Intriguingly, despite the accelerated subsurface warming, the annual amplitude of ground surface temperature decreased from 29.0 ± 2.8 ℃ to 24.5 ± 3.6 ℃ following talik formation, likely due to the buffering effect of increased vegetation cover, which modified the surface energy balance. Our results demonstrate that climatic warming and wetting can initiate a cascade of internal feedbacks, propelling marginal permafrost beyond an abrupt tipping point. These findings emphasize the acute vulnerability of marginal permafrost and highlight the urgent necessity for sustained monitoring to assess ecosystem stability and quantify associated greenhouse gas emissions.

Groundwater is essential for maintaining public health, promoting economic development, and ensuring ecosystem stability in arid and semi-arid regions. The northwestern Ordos Basin (China) primarily relies on groundwater from multilayered aquifer systems; however, our knowledge of the hydrochemical characteristics and water quality of groundwater in this region is limited. Here, we employed a newly collected dataset of 94 groundwater samples from different aquifers to constrain the source, controlling processes of fluoride in groundwater, and its potential health risk in the area. Groundwater is characterized by Na-Cl and Na-SO₄ types with a minor Na-HCO₃ type, which is primarily controlled by ion exchange, silicate weathering, and the dissolution of carbonate and evaporite minerals. Of the groundwater samples, 42% exceeded the fluoride limit of 1.5 mg/L established by the World Health Organization (WHO). This is mainly attributed to geogenic sources, including fluorine-bearing mineral dissolution, cation exchange, evaporation, and competitive adsorption. The water quality index suggests that most samples are unsuitable for drinking. Health risk assessment results based on the Monte Carlo simulation indicate that children face significantly higher non-carcinogenic health risks from fluoride exposure than adults (both males and females). These findings provide new insights into the complex hydrogeochemical evolution of fluoride in groundwater and the groundwater quality status in multi-aquifer systems, contributing to the sustainable development and management of groundwater resources in the Ordos Basin.

This paper presents the morphologic, chemical and other typomorphic characteristics of native gold from four placer deposits (basins of the Lev. Nora, Skalistaya and Golysheva rivers, and Loginova brook), four placer occurrences (basins of the Lagernaya, Nizh. Litke and Prokhodimaya rivers, and Tikhiy brook), and the alluvial deposit of cape Mordovin on Bolshevik island of the Severnaya Zemlya archipelago (Russia). Optical microscopy, scanning electron microscopy and electron-probe microanalysis were used in this study.

Placer gold from the Lagernaya, Golysheva, Nizh. Litke and Skalistaya rivers, Tikhiy brook and cape Mordovin is characterized by a very high fineness (> 988‰) in the rims and a lower fineness (860‰-970‰) in the center. Gold particles from the placers of the Lev. Nora and Prokhodimaya rivers and Loginova brook are low fineness and widely vary in the center (from 647‰ to 920‰) and are high fineness (950‰-980‰) in the rims. In some gold particles from the placers of the Lev. Nora and Skalistaya rivers, zones with Cu up to 1.2 wt.% and Hg up to 2.6 wt.% are observed. Titanite, monazite, cobaltite, ulmannite, brannerite, rutile, zircon, Y-xenotime, bismuthite, native bismuth and bismuthinite, garnet (almandine), Cu- or Ni-pyrrhotite were found in the native gold from the Skalistaya and Lev. Nora placers. Native gold from the Skalistaya river placer contains mineral micro-inclusions of cobaltite, Cu,Cd-bearing sphalerite and Fe,Cu-ullmannite. Native gold from the Lev. Nora river placer differs in the presence of brannerite and bismuth minerals.

On the basis of the obtained results, available metallogenic characteristics of Bolshevik island and literature data, the following types of primary sources are predicted for these locations: (1) Lev. Nora river deposits of gold-copper rare metal and porphyry gold-copper formations; (2) Skalistaya river deposits of porphyry gold-copper and gold-quartz formation; (3) all the other locations: deposits of gold-quartz and gold-sulfide-quartz formations (hosted in terrigenous carbonaceous complexes). The presence of intermediate reservoirs near some of these locations is probable.

The origin of magnesium and iron isotope variations in mafic-ultramafic rocks has long been debated. In particular, a substantial lack of understanding exists regarding how the variation in the Mg and Fe isotopic compositions of arc magmas relates to fractional crystallization. Here, we report new Mg and Fe isotopic analyses of mafic-ultramafic rocks formed by co-genetic magmatic evolution in the Eastern Kunlun orogenic belt. The ultramafic and gabbro samples present mantle-like Mg isotopic compositions, with δ²⁶Mg values ranging from −0.279‰ to −0.266‰ for wehrlite, −0.266‰ to −0.243‰ for clinopyroxenite, and −0.284‰ to −0.253‰ for gabbro. In contrast, the δ²⁶Mg values of the hornblende gabbro samples are significantly higher (−0.195‰ to −0.176‰). These rocks have similar heavy Fe isotopic compositions, with δ⁵⁶Fe values ranging from 0.020‰ to 0.157‰. The high δ²⁶Mg values observed in the hornblende gabbro are interpreted as indicating a maximum of 6% olivine fractionation, whereas the slightly high δ²⁶Mg values in the clinopyroxenite are ascribed to the accumulation of titanomagnetite. The Fe isotopic signatures of these rocks are inherited from magmatic sources. A comparison of the studied rocks with other mafic-ultramafic rocks implies that partial melting of mantle wedges induced by metasomatism of marine sediment-derived melts could generate “dry” arc magmatism, which would necessitate a more comprehensive and detailed analysis in further investigations.

Light hydrocarbons (LHs) are key components of petroleum, and the carbon isotopes composition (δ¹³C) of individual LHs contains a wealth of geochemical information. Forty-four oil samples from five different basins were analyzed using gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), and gas chromatography-isotope ratio mass spectrometry (GC-IRMS). The δ¹³C values of forty-three LHs were recognized and determined by comparing the GC and GC-IRMS methods. The results revealed significant differences in δ¹³C distribution characteristics among different LH compounds. The δ¹³C variation of individual LHs in iso-paraffins showed the widest range, followed by cycloalkanes and aromatics, whereas the δ¹³C variation in n-paraffins showed the narrowest range. The δ¹³C values of most individual LHs are primarily affected by the source facies and thermal evolution. Among them, c-1, 3-dimethylcyclohexane (c-1, 3DMCH) is mainly sourced from higher plants but may also form through abiotic mechanisms such as catalysis or cyclization. The δ¹³C values of c-1, 3DMCH (δ¹³C_{c-1, 3DMCH}) primarily exhibit parental genetic characteristics, enabling effective distinction of oil from different source facies. Specifically, the δ¹³C_{c-1, 3DMCH} in marine oils, lacustrine oils, terrigenous oils, and coal-formed oils are < -22‰, from -22‰ to −20.2‰, from −20.2‰ to −18.4‰, and > −18.4‰, respectively. Moreover, maturity is the primary controlling factor for δ¹³C values of 3MC₇ (δ¹³C_3MC7, 3MC₇: 3-methylheptane), while the source facies serve as a secondary influence. The plot of δ¹³C_{c-1, 3DMCH} and δ¹³C_3MC7 was introduced to classify source facies. As δ¹³C_{c-1, 3DMCH} and δ¹³C_3MC7 increase, the source facies transits from marine to lacustrine, then terrigenous, and finally coal facies. Additionally, increasing δ¹³C_3MC7 indicates a relative increase in maturity. Therefore, the δ¹³C_{c-1, 3DMCH} vs. δ¹³C_3MC7 plot serves as an effective tool for distinguishing source facies and assessing relative maturity.

The paper deals with the urgent problem of gas-geochemical parameters in the seas and shelf transit zones based on a comparison of field studies and remote sensing data. The results of complex gas-geochemical studies of the Daginsky gas-hydrothermal system are presented, as well as an assessment of methane emissions from the studied area. The Daginsky gas-hydrothermal system is located on the northeastern coast of Sakhalin Island, and is a unique object due to a combination of a number of factors: from zonality due to the proximity of the Okhotsk Sea and the geological structure, to the interaction of deep and surface processes manifested in the presence of biogenic and thermogenic methane, as well as mantle helium. Tectonic faults and oil and gas bearing structures of the northeastern shelf of Sakhalin, which determine the direction of natural gas flows and facilitate its migration to the surface, make a sig-nificant contribution to the gas appearance of thermal springs. The main gas is methane up to 90%, homo-logues of methane up to and including pentane have been established, and isolated high concentrations of helium and hydrogen, both dissolved and in the free gas of bubbles, have also been noted. The con-ducted isotope studies allow to speak about the complex genesis of the gas. δ¹³ C isotopic composition, ranging from −49.4‰ to −60.2‰ shows the dominance of biogenic methane with an admixture of ther-mogenic component. This is also confirmed by the presence of a fraction of mantle helium. The flow of methane into the atmosphere from the Daginsky area is 963757.5 mol/(km² day), or about 15.4 t/(km²-year), which indicates the importance of this region for the regional and global carbon cycle. The dynam-ics of methane emissions can vary depending on various factors, such as seasonal fluctuations and geological activity, which further complicates the understanding of processes in the region.

Energy security is a crucial aspect of modern societies, as it directly impacts the availability, accessibility, and reliability of energy sources. The reliance on natural resources and geopolitical factors in shaping energy security has gained significant attention in recent years. Natural resources and geopolitical risk are examined in 38 countries at risk of geopolitical conflict between 1990 and 2021 by examining CO₂ emissions, renewable energy consumption, and foreign direct investment as controlling variables. The long-run analysis conducted in this study focused on slope heterogeneity, Westerlund cointegration, and dynamic panel data estimation. The findings indicated that the energy security index is positively associated with various determinants, including natural resources, geopolitical risk, CO₂ emissions, and renewable energy consumption. However, foreign direct investment was found to be negatively associated with the energy security index among the selected 38 geopolitical risk countries. The role of natural resources and geopolitical risk in energy security cannot be overlooked. Natural resources provide the raw materials for generating electricity and powering our societies, while geopolitical risks can disrupt energy supply chains and threaten stability. Achieving sustainable energy security requires a comprehensive approach that addresses both aspects of energy provision. Transitioning to renewable energy sources, improving energy efficiency, diversifying energy supplies, promoting international cooperation, and conserving natural resources are essential steps towards a more sustainable and resilient energy future.