Geosciences doi: 10.3390/geosciences16090380

Authors: Stephanie L. Latour Norman L. Jones Stephen T. Nelson John McBride Kevin A. Rey Benjamin C. Barton

Understanding the role of faults in directing groundwater flow within bedrock aquifers is crucial, especially in the arid Southwestern United States, where water demand is exceptionally high. This study investigates the confined Coconino aquifer (Permian, 282–270 Ma), located between Springerville and Saint Johns, Arizona, and supplying the Springerville Generating Station. Using abundant well-pumping and water-level data, we analyzed how distinct regional geological structures, specifically the Coyote Wash fault (a steeply dipping normal fault; initially 70–30 Ma old with subsequent middle-to-late Quaternary and younger activity (<750 ka), the Cedar Mesa anticline, and the Buttes anticline, control local groundwater movement. Although the parallel Coyote Wash and Cedar Mesa structures experience similar regional stresses, model calibration yields hydraulic characteristics (hydraulic conductivity divided by barrier thickness) of 1.0 1/day for the Coyote Wash fault and 0.0001 1/day for the Cedar Mesa anticline, four orders of magnitude lower. Seismic reflection profiling reveals a disrupted zone, roughly 200 m wide, associated with the Cedar Mesa structures. Because these faults are perpendicular to the maximum horizontal stress direction, prevailing compressive forces theoretically close fracture apertures and severely restrict water flow. However, this study reveals that highly permeable regions exist where the structural damage zones of these prominent faults overlap. Ultimately, even in restrictive geological environments where ambient stresses predict sealed fractures, the overlapping damage zones of multiple intersecting faults can unexpectedly generate critical, highly permeable pathways for sustained deep groundwater flow today.

Geosciences doi: 10.3390/geosciences16090379

Authors: Marianna Cangemi Ygor Oliveri Salvatore Inguaggiato Rocco Favara Paolo Madonia

Hydrothermal aquifers are natural systems useful for understanding deep fluid–rock interaction processes and, in particular, the fate of strategic raw materials, such as Rare Earth Elements (REE). This study investigates the geochemical behavior of dissolved REEs in hydrothermal systems of western Sicily (Italy), a tectonically active area of the south Mediterranean. These waters are discharged at a wide range of temperatures (18 °C to 56.1 °C) and electrical conductivities (0.81 to 35.06 mS cm−1). Three major hydrochemical groups were individuated in the Langelier–Ludwig diagram: Group I (chloride–sulfate alkaline waters, with a seawater-like composition), Group II (chloride–sulfate earth-alkaline waters), and Group III (bicarbonate earth-alkaline waters, governed by CO2 circulation). Total dissolved REE concentrations variate in a two-order magnitude range, from 10.2 to 954 ng L−1. Patterns of shale-normalized REE show a progressive enrichment from light (LREE) to heavy (HREE) REEs, together with persistent negative Ce (Ce/Ce∗ = 0.16–0.88) and prominent positive Eu (Eu/Eu∗ = 1.87–4.42) anomalies. A shallow oxidative scavenging of Ce onto iron oxyhydroxide surfaces (Ce3+ → Ce4+) is suggested by its negative anomaly. The strong positive Eu is attributed to the preferential leaching of Eu2+ from feldspars, occurring at high temperatures at depth, before the upwelling of hydrothermal fluids. The amplitude of the third (T3) and fourth (T4) lanthanide tetrad effects was used for reconstructing the non-CHARAC (Charge And Radius Controlled) fractionation pathways, isolating distinct trajectories: Group I and II fluids are characterized by combined tetrad amplitudes, driven by the competitive complexation between un-fractionated deep sulfate/halide species and shallow, highly fractionating carbonate ligands. Furthermore, the middle-REE (δMREE) enrichment highlights interactions with fluids circulating in evaporitic deposits, and iron reductive dissolution by deep gas forcing. This comprehensive REE behavior is a useful geochemical tool for the characterization of the low-to-medium enthalpy geothermal systems in the south Mediterranean structural domain.

Geosciences doi: 10.3390/geosciences16090378

Authors: Mauricio Secchi Massimo Mangifesta Nicola Sciarra

Calibration of debris-flow models is important for reproducible hazard mapping, transparent scenario analysis, and risk-informed territorial planning. Reliable calibration of debris-flow models is limited by parameter uncertainty, non-uniqueness, and the loss of spatial information when observations are reduced to scalar targets. This study presents a global–local full-flowfield inversion framework for estimating effective Voellmy friction parameters from complete final-thickness rasters, thereby replacing subjective trial-and-error adjustment with an explicit forward–inverse workflow and a spatially distributed objective function. A two-dimensional finite-volume shallow-flow solver is coupled with a genetic algorithm for bounded global exploration and projected finite-difference gradient descent for local refinement. The composite objective combines thickness, wet footprint, signed boundary distance, and total volume mismatches. The framework was evaluated through controlled parameter recovery, objective profiling, ten-seed repeatability tests, observation perturbations, conditional identifiability analysis, and a controlled Morino–Rendinara back-analysis retrieval test based on a published real-event parameterization and the real terrain. Uniform reference coefficients of 0.10, 0.25, and 0.45 were recovered with a mean absolute error of 1.90×10−4 and exact wet footprint agreement. Across ten baseline inversions, the standard deviation of the estimate was 1.53×10−4. Random removal of up to 50% of observation cells had negligible influence, whereas thickness noise and systematic scaling produced larger deviations; at 20% noise, mean IoU remained 0.9861. Prescribing ξ between 250 and 1000 m s−2 shifted the estimated μ from 0.243038 to 0.254628 despite nearly identical final deposits, demonstrating conditional identifiability. In the two-zone experiment, the framework recovered μup=0.009991 and μdown=0.100184, with a held-out RMSE of 4.49×10−5 m and IoU equal to one. Full-flowfield inversion therefore provides accurate and reproducible event-specific parameter retrieval.

Geosciences doi: 10.3390/geosciences16090377

Authors: Mingyang Zhong Peng Jia Hongyuan Liu

Variations in the electrical signals of rock masses can reflect the development of internal fractures, pore fluid migration, and damage evolution, showing broad potential for the monitoring and early warning of engineering rock mass disasters. In recent years, with the continuous development of electrical resistivity tomography, time-lapse electrical monitoring, digital rock technology, and multiscale numerical simulation, research on rock mass electrical properties has gradually expanded from traditional resistivity measurements to fracture evolution characterization, damage identification, and instability precursor prediction. However, the electrical responses of rock masses are governed by multiple interacting factors, and different physical processes may produce similar or even opposing electrical anomalies. Existing studies have largely addressed conduction theories, monitoring methods, and engineering applications as separate aspects, while a systematic understanding of the mechanisms governing rock-mass electrical responses under different conditions, as well as their intrinsic relationships with conductive network evolution, remains lacking. This review is mainly based on 153 representative publications indexed in the Web of Science Core Collection from 1998 to 2026 and systematically summarizes research progress on the electrical responses of rock masses over nearly three decades. With the conductive network as the central theme, this review comprehensively analyzes multiphase conduction theories, electrical monitoring techniques, conductive network evolution mechanisms, and engineering applications. Rock mass electrical responses originate from the charge transport process within the internal multiphase conductive network. The propagation of fractures, variation of pore structures, fluid migration, and multi-physics coupling continuously change the number, connectivity, and spatial distribution of conductive paths, thereby resulting in dynamic variations of electrical parameters such as resistivity. As rock masses evolve from stable damage to critical instability, the conductive network gradually shifts from local adjustment to rapid reconstruction and critical connectivity, accompanied by abrupt changes in resistivity, enhanced electrical anisotropy, and temporal anomalies. Even during quiet periods of acoustic emission, resistivity can continuously reflect crack propagation and conductive network reconstruction, providing complementary information for the identification of instability precursors. The main contribution of this review is to link the multiphase conduction mechanisms, electrical monitoring methods, resistivity variation characteristics, and damage-to-instability processes of rock masses and to systematically summarize the intrinsic relationships among charge transport, conductive network reconstruction, macroscopic electrical responses, and rock damage and instability. On this basis, an integrated analytical framework from conduction mechanisms to damage characterization and instability precursor identification is established, providing new insights into establishing quantitative relationships among conductive network structure, charge transport processes, and electrical responses, as well as developing electrical theories and intelligent monitoring and early-warning methods for rock masses under multiscale and multi-physics coupling conditions.

Geosciences doi: 10.3390/geosciences16090376

Authors: Ke Xu Yixiong Hu Hui Zhang Wei Ju Weike Ning Penglin Zheng Jiajun Zhang Zhongwei Zhang Qiuyu Chen Yuanhang Qi

Significant progress has been made in exploring ultra-deep tight sandstone gas in the Tarim Basin, but sweet spot prediction remains challenging in the Keshen block of the Kuqa Depression. Based on integrated geological, experimental, and seismic data, this study characterizes the geomechanical properties and in situ stress field of the Cretaceous Bashijiqike Formation and identifies the main controls on reservoir quality. 3D geomechanical modeling and finite element simulations reveal that fracture development, stress–fracture angle, structural style, and the absence of stress concentration jointly govern reservoir favorability. Stress concentration can coexist with fracture development due to differential sandstone–mudstone deformation, leading to fracture deactivation. Favorable reservoirs occur in structural positions with extensive natural fractures, moderate principal stress–fracture angles, and low stress concentration. Coupling between in situ stress and natural fractures is the key to sweet spot prediction. The proposed geomechanical workflow improves precise identification of engineering and geological sweet spots, enhancing exploration and development efficiency in ultra-deep tight gas reservoirs.

Geosciences doi: 10.3390/geosciences16090375

Authors: Cai Li Tong Qin Teng Liu Dongjia Hou Fei Ma

The Paleogene deep tight glutenite reservoirs in the Bohai Sea area feature strong heterogeneity and complex pore structures, posing significant challenges to the seismic prediction of sweet-spot reservoirs. Uncertain reservoir-sensitive factors and insufficient large-angle information from seismic gathers, together with the low accuracy of conventional prestack density inversion, lead to considerable porosity prediction errors and make it difficult to identify high-quality reservoirs. To address these issues, this study proposes a novel prestack density inversion method constrained by an elastic decoupling factor (EDF) for porosity prediction in tight reservoirs. First, rock physics modeling is performed using a variable aspect ratio Xu–White model, based on which a reservoir-type indicator and a porosity-sensitive factor are constructed to establish differentiated solution equations among density, Poisson’s ratio, and porosity. Second, to overcome the strong dependence of density inversion on large-angle information, an EDF is formulated to decouple density from S-wave impedance, thereby reducing inversion non-uniqueness. Simultaneously, compressed sensing technology based on L1-norm regularization and basis pursuit is introduced to obtain high-resolution P-wave impedance, S-wave impedance, and Poisson’s ratio, providing high-quality inputs for density decoupling. Based on the above methods, the solution equations between density and porosity are integrated to achieve classified and quantitative porosity prediction for tight reservoirs. Application to the deep Kongdian Formation glutenite reservoirs in the Bozhong 28 area, Bohai Sea, shows that the predicted porosity matches measured porosity with an accuracy of 82% (average relative error of 18.5%), and the correlation coefficient of the inverted density is improved from 62% (conventional simultaneous inversion) to 85%. Furthermore, an approximately 10 m thick mudstone interlayer is clearly resolved. Blind well BZ28-L validation confirms good agreement between predictions and actual drilling data. This work provides a valuable reference for sweet-spot prediction in similar deep fan-delta tight reservoirs.

Geosciences doi: 10.3390/geosciences16090374

Authors: Serik Moldabayev Alikhan Khairullayev Olena Sdvyzhkova Dmytro Babets Samal Assylkhanova Nurzhigit Sarybayev

Designing interlevel pillars for deep, structurally complex vein deposits requires balancing rock mass stability against ore recovery. This study evaluates the geomechanical response of the Kenzhem area of the Akbakay gold deposit using a three-dimensional finite-element model that reproduces the lithological structure, irregular ore-body geometry, underground workings, and mined-out stopes. Four extraction scenarios were analyzed: complete extraction without pillars and mining with 10, 15, and 20 m inter-stope pillars. Stability was assessed using maximum total displacement, the extent and connectivity of yielded zones predicted by the generalized Hoek–Brown criterion, and numerical convergence. Pillarless extraction produced displacements of 2.6–3.0 m, a continuous yielded zone extending toward the surface, and loss of numerical convergence. A 10 m pillar reduced displacements to 0.50–0.66 m but did not provide a stable equilibrium state. Increasing the pillar thickness to 15 m reduced the maximum displacement to approximately 0.08 m, localized the yielded zones near excavation boundaries, and ensured convergence. A 20 m pillar produced only a minor additional reduction to 0.065–0.070 m without materially changing the failure pattern. Therefore, a 15 m inter-stope pillar provides the most rational balance between geomechanical safety and ore recovery under the investigated conditions.

Geosciences doi: 10.3390/geosciences16090373

Authors: George H. Scott

The International Code of Zoological Nomenclature provides, under its principle of priority, that a name that has been declared a synonym of an earlier proposed species remains contestable and open to future research. However, as the Code is concerned with nomenclature and not with taxonomic concepts, it places no restrictions on declarations of synonymy, enabling them to be published without supporting evidence. This freedom, which is at the core of the synonymy ‘problem’, contributes to taxonomic inflation and constrains estimates of diversity. From a theoretical perspective, evidence in an unsupported declaration devolves to that of one specimen, the holotype. Furthermore, in the absence of other evidence, the declaration further devolves to one of opinion, with readers left to judge its value based on their knowledge of the declarator. This approach, based on typification, is contrasted with one in which a species exists independently of our perception and is viewable as samples of its local populations. Rather than an arbiter of usage, the holotype then acts only as a referent to its local source population, whose properties define much of the species concept. A worked example of these concepts using data from the planktonic Foraminifera supports the view that evidence of synonymy lies in the source populations of the holotypes.

Geosciences doi: 10.3390/geosciences16090372

Authors: Antoon Kuijpers Marit-Solveig Seidenkrantz

Greenland Ice Sheet (GrIS) melting occurred during the later part of the Holocene Thermal Maximum (HTM) with a well-documented significant GrIS retreat between 7 and 3 ka. However, less is known about the immediate melt water impact on Greenland fjord hydrography and more distant ocean circulation. A compilation of published sediment records from southwest Greenland fjords and Disko Bay, West Greenland, demonstrates marked local erosional events and deposition of extensive (silty) melt water sediments within the period 4.4 to 3.2 ka BP. The termination of fjord perturbation in this region is dated at c. 3.2 ka and closely corresponds to the reported timing of minimum GrIS extent. As an ocean response, an increased freshening and enhanced melt water transport by the Labrador Current (LC) between 4.4 and 4.0 ka are concluded to signal the most prominent melt water discharge events in the southwest Greenland fjords. The latter melt water pulses were coeval with a marked warming episode and negative surface mass balance peak recorded in ice cores. As suggested by modelling and paleo-oceanographic records from the North Atlantic subpolar gyre, temporarily enhanced GrIS melting and increased LC freshwater release into the North Atlantic around 4.2 ka may have led to destabilization of the AMOC. The GrIS melt water surges associated with an anomalous atmospheric (Greenland blocking) regime are proposed to reflect a regional climate anomaly related to the so-called ‘4.2 ka BP event’.

Geosciences doi: 10.3390/geosciences16090371

Authors: Demetris Koutsoyiannis

A novel axiomatic foundation of entropy has recently been proposed, overcoming the limitations of classical and information-theoretic entropy foundations and eventually unifying probabilistic and physical entropy. A new set of postulates leads to a rigorous, uncertainty-based definition of entropy consistent with the principle of maximum entropy. Entropy is thus a purely stochastic concept quantifying uncertainty, thereby enriching Kolmogorov’s probability system. Applied to gas thermodynamics, the new framework reproduces classical results and derives, rather than assumes, the laws of thermodynamics. In atmospheric applications, entropy maximization yields an isothermal state as the molecular equilibrium. Gravitation does not alter the isothermal state but differentiates it from the isentropic one of macroscopic air parcels, whose motion drives the atmosphere away from equilibrium. Radiatively active gases, through interactions with shortwave and longwave radiation, sustain non-equilibrium vertical profiles of the atmospheric variables. Combined with the Stefan–Boltzmann law, these mechanisms provide a simple, parsimonious, and coherent explanation of observed atmospheric behaviors and the climatic system. The framework highlights thermodynamics as emergent from stochastics, offering new insights into molecular uncertainty, emergence of macroscopic structures, and radiation in shaping Earth’s climate. It also suggests a broader stochastic view of nature and atmospheric processes.

Geosciences doi: 10.3390/geosciences16090370

Authors: Aleksandra Kropczyk Adrian Marciszak

A verification of materials from museum and private collections was conducted from six caves at Połom Mount, dating from the Middle Pleistocene to the Holocene, and seven rock shelters from nearby Miłek Mt, dated to MIS 2–1. The analysis revealed the presence of five canid species and several of their associated chronosubspecies. Lycaon lycaonoides from the Południowa Cave and Cuon alpinus fossilis from Wschodnia Cave were the least frequently represented, with single finds. Canis lupus, the most abundant, is known from nine sites dated to MIS 8–1. Among these, the finds from Naciekowa, Obok Wschodniej, and Wschodnia Caves stand out, representing some of the oldest and first appearances of large-bodied wolves in Europe in MIS 8. These records document the eastern migration of the species. Canis lupus from these sites is only slightly smaller in size and differs slightly morphologically, although the scale of these features is like that of the contemporary Canis lupus lupus from Silesia. It represents a slightly lower level of evolutionary development, and its morphology still displays some features of Canis lupus lunellensis, although their scale of development is smaller. Given the enormous metric and morphological diversity of extant Canis lupus lupus, and comparing the analysed material from the Naciekowa, Obok Wschodniej, and Wschodnia Caves with several late Middle Pleistocene European sites dated MIS 10–6, the material from these sites was classified as belonging to Canis lupus lupus or Canis lupus ssp. Although several chronosubspecies were established in the MIS 9–6 period, the only reliable criterion, according to the authors, was size, which was used rather arbitrarily to create new chronosubspecies. The enormous variability of Canis lupus, as mentioned above, or local, geographic, and environmental conditions, were not considered. The analysis revealed no basis for classifying the material from the Naciekowa, Obok Wschodniej, and Wschodnia Caves as anything other than Canis lupus lupus. Only bones from the Północna Duża Cave belong to a particularly great and robust Canis lupus spelaeus, a member of the mammoth steppe fauna. These morphological features were specialised adaptations for hunting and scavenging large ungulates and were associated with processing frozen carcasses. Remains of Vulpes vulpes, the second most abundant canid species in Sudetic caves, were found in the Late Pleistocene and Holocene horizons of many localities. On the contrary, Vulpes lagopus is a rare faunal element of the Sudetic paleoassemblages. Specimens of both species from Sudetic caves are large and robust but fall within the upper range of variability of the species from the Late Pleistocene of Eurasia. Similarly, no particular morphological differences have been found between the Late Pleistocene, Holocene, and extant Silesian Vulpes vulpes and Vulpes lagopus. The accumulation and deposition of canid remains in Sudetic caves was rather incidental because of abiotic factors or carnivore activity. Direct proof of human exploitation of canids is marginal.

Geosciences doi: 10.3390/geosciences16090369

Authors: Yang Liu Junhui Li Ran Xiong Bo Yan Rui Deng Yuangao Zhang Xiandong Wang Yong Zhong Yanqing Cao Shan Zhao

The Cambrian platform-margin shoals in the Yudu area, Tarim Basin, are important targets for deep and ultra-deep hydrocarbon exploration, but their development and reservoir-forming mechanisms remain poorly constrained. This study integrates 3D seismic interpretation, drilling and logging data, core observations, thin-section petrography, and reservoir characterization to investigate shoal architecture, reservoir characteristics, and controlling processes. Seismic data reveal that multistage, basinward-prograding carbonate buildups developed along fault-controlled platform-margin slope breaks adjacent to the Yudu rift trough. Core and petrographic observations show that the shoals are dominated by granular, microbial, algal, and oolitic dolomites, with intercrystalline, dissolution, vuggy, and fracture-related pore systems. High-quality reservoirs are preferentially developed within thick, vertically stacked shoal complexes and are characterized by strong heterogeneity and locally enhanced porosity and permeability. Early dolomitization favored the preservation of primary pore frameworks, whereas subsequent faulting and multistage dissolution generated and enhanced fracture–vuggy reservoir space. The spatial association between platform-margin shoals and the Yudu rift trough further provided favorable conditions for near-source hydrocarbon accumulation. These results demonstrate that Cambrian reservoir development was governed by coupled tectono-sedimentary and diagenetic processes and highlight fault-controlled platform margins as favorable targets for deep and ultra-deep carbonate exploration.

Geosciences doi: 10.3390/geosciences16090367

Authors: Feng Zhang Qili Xie Yong Zhang Jinyang Li Jingsong Yi Qing He Lu Jiang Ping Wang Shilong Sun

Climate-driven extreme rainfall is increasing landslide risk, whereas conventional regional rainfall thresholds inadequately represent spatial variations in slope preconditioning across complex mountainous terrain. This study develops a dynamic early-warning framework that couples slope unit landslide susceptibility with rainfall triggering for Jinyang County, Southwest China. The county was divided into 7249 slope units, and eight conditioning factors were used to train support vector machine (SVM) and extreme gradient boosting (XGBoost) models with Bayesian hyperparameter optimization. Bayesian-optimized XGBoost (BO-XGBoost) achieved the best discrimination, with an area under the curve (AUC) of 0.893. For temporal triggering, 113 historical rainfall-landslide events were analyzed in logarithmic intensity–duration (I–D) space. A power-law fit described the central trend, and the fifth percentile of residuals defined a 5% non-exceedance threshold exceeded by approximately 95% of triggering events. Residual-based thresholds were used to establish four rainfall-trigger levels. A gated risk matrix coupled these levels with susceptibility classes. Validation using 162 online monitoring sites during the 21 August 2023 extreme rainfall event yielded 85.2% accuracy, 83.6% precision, 81.2% recall, 88.2% specificity, and an F1 score of 82.4%, demonstrating practical potential for spatially refined regional landslide early warning.

Geosciences doi: 10.3390/geosciences16090368

Authors: Koji Wakita Tatsuru Nishio

Inclusive geotourism has attracted increasing attention as geoparks seek to broaden opportunities for diverse people to experience geoheritage. However, its practical implementation remains limited, and previous studies have focused primarily on accessibility rather than participation. This study examined the current status, challenges, and broader implications of inclusive geotourism in Japanese geoparks through a nationwide questionnaire survey, a questionnaire survey at a special needs school, field evaluations, and a collaborative workshop. The results indicate that inclusive geotourism remains at an early stage of development. Although many geoparks recognize the importance of accessibility, implementation remains limited, particularly for people with sensory, cognitive, and less visible disabilities. The principal challenges extend beyond physical accessibility to include knowledge, communication, experience, organizational capacity, and collaboration. This study proposes “One Geopark, One Universal Design Course” as a practical framework for expanding opportunities for participation. More fundamentally, it suggests that inclusive geotourism should be understood not only in terms of accessibility but as a complementary dimension of geotourism that broadens participation by diverse visitors and local residents. Together with previous research, these findings suggest a potential pathway through which broader participation may contribute to the social sustainability of geopark communities, although this requires further empirical investigation.

Geosciences doi: 10.3390/geosciences16090366

Authors: Yu Jiao Mengmeng Tao Yuan Wang Di Feng Zhikui Wang Jie Ren

Accurately evaluating the effective stress coefficient (α) of rock fractures under hydro-mechanical (HM) coupling is paramount for assessing the stability of fractured rock in deep underground engineering. This study conducted triaxial HM tests under varying normal stresses and multi-stage fluid pressures on marble fractures from a deep-buried water transport tunnel. Coupled with numerical simulations, the dynamic evolution and mesoscopic physical mechanisms of α under complex stress paths were elucidated. Results demonstrate that α is highly stress-dependent and generally less than 0.4 for smooth marble fractures. Under low normal stress, α increases approximately linearly with elevated fluid pressure. Conversely, under high normal stress, α exhibits low sensitivity to fluid pressure variations until surpassing a critical threshold (10–12 MPa), after which it manifests a pronounced exponential increase. Mesoscopic analysis reveals that severe contact occlusion induced by high normal stress restricts fluid permeation, leading to a heterogeneous fluid pressure distribution. This heterogeneity restricts the applicability of the traditional effective stress principle under extreme conditions. Once fluid pressure crosses the threshold, a “wedging effect” triggered by high-pressure fluid forces rapid failure of contact spots, causing a precipitous reduction in the contact area ratio (Sc). This contact state evolution constitutes the physical essence underlying the exponential surge of α. Based on experimental and inverted data, an improved empirical model for fracture effective stress was established, incorporating the coupled influences of normal stress and fluid pressure. This model possesses explicit physical significance, providing a scientific theoretical basis for evaluating surrounding rock stability in deep-buried tunnels.

Geosciences doi: 10.3390/geosciences16090365

Authors: Leul Fisseha Zemichael Tesfamichael Gebreyohannes

Reliable estimation of aquifer transmissivity (T) is fundamental for groundwater assessment, development, and sustainable management. Although pumping tests provide the most reliable estimates of transmissivity, their application is often constrained by the limited availability of wells and the high cost of testing, particularly in data-scarce regions such as the Raya Valley, northern Ethiopia. This study evaluates the potential of electrical transverse resistance (Tr), derived from Vertical Electrical Sounding (VES), as a proxy for estimating transmissivity in unconsolidated aquifers. A total of 44 VES datasets integrated with pumping test data from nearby wells were used to develop empirical T–Tr relationships. The Schlumberger electrode array was employed with a maximum current electrode spacing (AB) of 1000 m, while an additional 263 VES datasets acquired between 1996 and 2024 were analyzed to characterize subsurface electrical variability. The results reveal strong linear relationships between transmissivity and transverse resistance. Normalization of transverse resistance to account for pore-water resistivity produced comparable relationships, with differences of only 1–3%, indicating that normalization provides limited additional benefit. Independent validation using 16 pumping-test datasets demonstrated excellent agreement between measured and estimated transmissivity values (R2 = 0.99). The transmissivity values used to develop the empirical equations ranged from 120 to 1180 m2/d. These relationships were derived specifically from unconsolidated aquifers within the Raya Valley and should therefore be applied within this hydrogeological context. Their applicability to confined sedimentary aquifers and fractured volcanic formations, which were not represented in the present dataset, remains uncertain. Further studies involving these hydrogeological settings are needed to evaluate and potentially extend the applicability of the proposed relationships. The developed T–Tr relationships provide a reliable and cost-effective approach for estimating transmissivity in saturated unconsolidated aquifers where pumping-test data are limited and may be transferable to hydrogeologically similar environments.

Geosciences doi: 10.3390/geosciences16090364

Authors: Marie-Christine Cacas-Stentz Alain Prinzhofer

Measurements of the soil’s surface for natural hydrogen exploration may be considered dubious due to several artefacts. For instance, drill bit metamorphism and superficial biological activity can induce hydrogen generation that is irrelevant for energy exploration. Furthermore, adsorbed hydrogen can be released through drilling and pumping operations. Here, we present a model of the hydrogen signal in soil when air containing traces of hydrogen is pumped out. According to this model, observed hydrogen recharge after several minutes would indicate active hydrogen flow during the measurements, whereas its absence may indicate adsorbed hydrogen in the soil or artefacts. This model allows us to quantify the hydrogen flow responsible for concentration anomalies in soils. It is consistent with the hypothesis that hydrogen emission from soils is not constant but rather occurs in the form of gas flushes over a period of a few days.

Geosciences doi: 10.3390/geosciences16090363

Authors: Wenqiang Wu Jiaoyang Yu

Two earthquakes greater than Mw 5.5 occurred in Dingri County, Tibet, between 2020 and 2025. Whether a triggering relationship exists between them remains debated. Therefore, in this study, we examine the kinematic mechanisms of the two events and seismogenic faults, as well as the post-seismic Coulomb stress changes. The results show that the maximum slip of the 2020 Dingri earthquake is 1.3 m at a depth of about 3.55 km, with a seismic moment of 6.53 × 1017 N·m, equivalent to an Mw = 5.8 earthquake. Regarding the 2025 earthquake, the maximum slip of F1 fault is 5.1 m at a depth of about 4.5 km, and the peak slip of the F2 fault is 0.46 m at a depth of about 2.5 km. With a seismic moment of 2.82 × 1019 N·m, the 2025 earthquake matches an Mw = 6.9 earthquake. The Dengmecuo fault exhibits a deformation rate of about 14.4 mm/yr, and the southern section of the fault is nearly locked before the 2025 earthquake, with a slip deficit of about 13.5 mm/yr. The Coulomb stress change five years after the 2020 earthquake is 10,700 Pa, which exceeds the threshold for triggering subsequent seismic activity, indicating a triggering relationship between the two earthquakes.

Geosciences doi: 10.3390/geosciences16090362

Authors: Assunta Donato Donatella Spadaro Sonia La Felice Dario Giuffrida Rosina Celeste Ponterio Catia Cannilla Gianna Vivaldo Ilaria Baneschi Simone D’Incecco Maddalena Pennisi

The eddy covariance (EC) technique is a key tool in environmental monitoring, enabling continuous and non-invasive measurement of carbon dioxide (CO2) fluxes at the ecosystem–atmosphere interface. In environments characterized by high levels of airborne particulates, such as volcanic regions, the reliability of enclosed-path EC measurements can be compromised by frequent filter clogging, potentially affecting data continuity, and increasing maintenance requirements. This study investigates whether the chemical and mineralogical signatures of particulate matter accumulated on clogged Swagelok pre-Licor filters can be used to identify dominant particle sources and provide insights into filter clogging processes. A multi-analytical workflow combining scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS), portable Raman spectroscopy, and hyperspectral imaging (HSI) was applied to recovered filter residues. The combined approach provided complementary chemical, mineralogical, and morphological information, allowing discrimination among volcanogenic material (e.g., glass shards, crystals, and lithic fragments), aeolian lithogenic dust, including Saharan inputs, and biogenic particles such as plant fibers. The results revealed two dominant particulate groups, volcanogenic mineral phases and biogenic material, with a minor contribution from wind-transported lithogenic dust. Volcanogenic phases, enriched in Si, Al, and Fe, dominated the inorganic fraction, whereas O-, C-, and N-rich particles were mainly associated with local biogenic sources. No clear evidence of significant anthropogenic contributions was identified. These findings demonstrate that multi-analytical characterization of particles accumulated on EC pre-filters can provide qualitative source attribution and valuable information on the processes responsible for filter loading and clogging. By linking particle characteristics with meteorological and environmental conditions, this approach has the potential to support site-specific, predictive, and event-driven maintenance strategies, contributing to improved EC data quality and more efficient long-term monitoring in high-aerosol environments.

Geosciences doi: 10.3390/geosciences16090361

Authors: Jiankuan Xu Yang Xu

Fault waviness can control whether earthquakes arrest, cascade, or transition to supershear rupture, yet its interaction with hypocentral position and free-surface proximity remains poorly constrained. We use three-dimensional spontaneous dynamic-rupture simulations of a vertical right-lateral fault containing one symmetric undulation. Its along-strike length L, transverse height H, signed nucleation distance, and upper-edge burial are varied under uniform regional stress and slip-weakening friction. Resolving the stress onto the non-planar surface creates a directional barrier–asperity pair. In surface-breaking models, small undulations permit cascading and sustained supershear rupture for all tested hypocenters, whereas larger undulations increasingly arrest rupture. The maximum height that permits position-independent cascading increases with undulation length, while the corresponding one-sided bend angle decreases from about 32° at L = 4 km to about 14° at L = 14–18 km. Burial suppresses shallow free-surface-induced supershear and narrows the cascading regime, but transmitted ruptures can still develop sustained or transient supershear at depth. Greater hypocentral distance generally favors transmission without monotonically favoring sustained supershear. These results show that fault geometry, rupture approach direction, hypocentral position, and surface proximity jointly control rupture connectivity and speed.

Geosciences doi: 10.3390/geosciences16090360

Authors: Junhua Luo Ting Luo Weiquan Zhao Wei Li

Landslide hazard assessment provides an important basis for regional geological disaster prevention and mitigation. Landslide hazard is commonly characterized in terms of three fundamental dimensions: spatial occurrence, temporal occurrence, and potential magnitude. Based on this conceptual framework, Guiyang, a typical mountainous city in western China, was selected as the study area, and slope units were adopted as the basic assessment units. First, eight topographic, geological, and hydrological conditioning factors were incorporated into an information-value model to evaluate the landslide susceptibility of each slope unit. The resulting min–max-normalized susceptibility index was used as the spatial susceptibility component. Second, the historical landslide inventory was combined with kernel density estimation, and a Poisson-based exceedance probability model was used to estimate the model-based exceedance probability of one or more landslides occurring in each slope unit under a 10-year scenario time window. This probability was used as the temporal component. Third, the potential landslide volume of each slope unit was predicted using machine-learning algorithms. The predicted small-, medium-, and large-volume classes were assigned ordinal magnitude weights of 1, 2, and 3, respectively, and were used as the magnitude component. Finally, the three components were integrated using a multiplicative composite index to obtain the relative landslide hazard of each slope unit. The results were as follows. The overall landslide hazard in Guiyang was dominated by medium and low hazard levels. Furthermore, 422 high-hazard slope units were identified, accounting for 15.58% of all slope units. These units were mainly concentrated in the central and northern regions. In terms of administrative divisions, Xifeng County, Kaiyang County, Xiuwen County, Qingzhen city, and Huaxi district ranked among the top five administrative regions with the most high-hazard slope units. Therefore, these regions should be considered key areas for disaster prevention and mitigation. Based on the hazard zonation, 21 selected high-hazard slopes were examined using UAV imagery and on-site inspection to document their representative geomorphological and deformation characteristics. The observations provided qualitative field support for the geological plausibility of selected high-hazard predictions. The findings of this study provide an important decision-making basis for landslide mitigation efforts by the Guiyang Municipal Government.

Geosciences doi: 10.3390/geosciences16090359

Authors: Aiko Nishizaki Shota Itoyama Yuichi Sugai

Simulating CO2 mineral trapping in basaltic formations requires geochemical reaction networks, but including all candidate reactions is often computationally prohibitive, and no established criterion exists for selecting a reduced yet representative set. We propose a two-stage reduction framework, motivated by the insight that trapping efficiency and pH buffer capacity are orthogonal criteria: a set that maximizes one is not guaranteed to satisfy the other. Stage A combines K-means clustering, Bayesian optimization, and a genetic algorithm to select reactions maximizing a trapping-efficiency score (J-score, integrating reaction extent, saturation state, and ionic contribution). Stage B independently verifies whether the selected set preserves pH buffer capacity (B-score), using CMG-GEM flow-coupled simulations validated against laboratory experiments. This two-stage check proved necessary: a set selected by J-score alone failed to converge in flow simulation due to excessive mineral precipitation, confirming that trapping efficiency alone is insufficient and identifying Anorthite as the dominant pH-buffering phase. A minimal two-reaction set (Anorthite and Dolomite) achieved a 94% reduction in computational cost under the present single-block column model, while maintaining pH fidelity against benchmark data; extrapolation of this efficiency gain to field-scale, multi-cell simulation remains a direction for future work. This framework reframes reaction-set selection from single-objective optimization to constrained design. The results are demonstrated for a single basaltic rock sample (Basalt Sample A); the approach is potentially transferable to reducing reaction-set uncertainty in other CO2-basalt mineralization systems, subject to lithology-specific recalibration.

Geosciences doi: 10.3390/geosciences16090358

Authors: Mikhail S. Turbakov Alexander A. Shcherbakov Evgenii P. Riabokon Zakhar G. Ivanov Pavel A. Kamenev Konstantin P. Kazymov Elena M. Tomilina Miroslav A. Pshevlodskii Yuliia S. Shcherbakova Evgenii V. Kozhevnikov

Large hydrocarbon fields are being developed in northern Sakhalin, whereas southern Sakhalin contains prospective resources hosted in unconventional, low-permeability siliceous source rocks. Their development requires stimulation to create conductive fracture networks, whose long-term integrity is critical for production feasibility. This study investigates permeability changes in four artificially fractured specimens subjected to cyclic confining pressure; the specimens are treated as case studies rather than as a statistically representative formation-scale data set. Cylindrical cores, 30 mm in diameter and approximately 30 mm long, containing an induced axial fracture were hydraulically tested under biaxial cyclic confinement. The tests showed irreversible loss of fracture conductivity, with residual permeability after unloading amounting to 7.1–37.4% of the initial value. Direct application of laboratory data to field scale fracture longevity models is inappropriate because cylindrical specimens develop nonuniform circumferential stresses and heterogeneous closure. A procedure is proposed to transfer core scale measurements to a planar fracture subjected to uniform normal stress in the rock mass. Fracture aperture was quantified by X-ray computed tomography (CT) and incorporated into a cell-based contact–hydraulic model accounting for geometric and hydraulic aperture. A nonuniform closure function was used to reconstruct the closure field and correct the laboratory results. At maximum pressure, Kmass/Klab ranged from 0.034 to 0.93 for the three specimens reproduced with acceptable fit; sample 3–4 was retained only as a diagnostic case because of its high root-mean-square error (RMSE). These values are model-based single-fracture scenario estimates pending direct-normal-loading validation.

Geosciences doi: 10.3390/geosciences16090357

Authors: Yanna Wu Jinning Zhang Yongxu Mei Wenjie Wang Peiye Liu Haodong Lin Yiming Cui Jiehao Su

The Chang 7 Member in the Zhidan area of the Ordos Basin is a strategic target for the exploration and development of continental shale oil. However, a systematic understanding of high-resolution sequence stratigraphic division, the spatial distribution of sand bodies and sedimentary facies, sedimentary evolution, and its controlling factors remains insufficient. Guided by high-resolution sequence stratigraphy, this study integrates core observations, well logging, and mud logging data from the Zhidan area. By employing signal processing techniques such as synthetic prediction error filtering analysis and well-to-well profile correlation, a high-precision sequence stratigraphic framework was established. Based on this framework, the spatial distribution of sand bodies and sedimentary facies was meticulously characterized, and the sedimentary evolution process along with its controlling factors was thoroughly discussed. The results indicate that the Chang 7 Member in the Zhidan area was deposited within a complete third-order cycle, which can be further subdivided into two fourth-order cycles. The sedimentary facies are predominantly characterized by a meandering river delta front–lake–turbidite fan system. From the Chang 73 to the Chang 71 depositional periods, the delta front prograded from north to south toward the center of the lake basin. Concurrently, the sand bodies evolved from thin-bedded deposits to multi-layered stacked and laterally extensive continuous deposits. The sedimentary infilling of the Chang 7 Member was synergistically controlled by tectonic subsidence, paleogeomorphology, paleoclimate, provenance supply, and base-level changes. As the base level transitioned from an accelerated rise to a decelerated rise, the depositional process shifted from retrogradation to progradation. This study not only provides significant insights into the sequence stratigraphy and sedimentary evolution of the Zhidan area but also holds great implications for promoting the exploration and development of continental shale oil and gas.

Geosciences doi: 10.3390/geosciences16090356

Authors: Viorel Carbune Maria Gutu Irina Cojuhari Lilia Rotaru Vladimir Melnic

Global Navigation Satellite Systems (GNSS) positioning accuracy is affected by multiple error sources, including atmospheric delays, multipath propagation, and receiver noise, which can significantly reduce positioning reliability in low-cost receivers. This study investigates the use of a feedforward neural network to compensate for positioning errors in a static GNSS receiver scenario. A synthetic dataset was generated in MATLAB/Simulink by simulating positioning perturbations around a known reference location. Consecutive coordinate differences were used as input features, and a compact feedforward neural network with 45 hidden neurons was trained using the Levenberg–Marquardt algorithm to estimate positioning error components. The proposed approach was evaluated through residual error distribution, regression, temporal dispersion, and spatial scatter analyses. The results indicate that, for the primary 10 m error scenario, neural network-based compensation reduced temporal dispersion by approximately 46% and produced a more compact spatial distribution of corrected positions around the reference location. The residual errors remained concentrated near zero, indicating improved positioning consistency under the investigated simulation conditions. Sensitivity analysis across nominal error radii of R95 = 1, 5, 10, 15, and 20 m showed consistent reductions in both RMSE and standard deviation for radii of 10 m and above, whereas no consistent improvement was observed at lower error levels. In a preliminary comparison with random forests, XGBoost, Long Short-Term Memory (LSTM), and Gated Recurrent Unit models using the same training, validation, and test samples, the Feedforward Neural Network (FNN) achieved competitive test MSE while requiring substantially less training time and runtime memory than the LSTM. These findings support the proof-of-concept feasibility of lightweight FNN-based correction for simulated static GNSS positioning. Future work will focus on validation using real GNSS measurements and extension to dynamic positioning applications.

Geosciences doi: 10.3390/geosciences16090355

Authors: Mark Torre Jorgenson Thomas A. Douglas Dana R. N. Brown William Brad Baxter James C. Walters Charles Henry Racine

Abandoned floodplains are complex landscapes in boreal permafrost regions due to diverse biogeomorphic effects that are highly modified by permafrost aggradation and degradation. We compiled biophysical properties for 150 cores at 135 sites with depths up to ~4 m on the Tanana Flats in central Alaska and developed depth profiles for bulk density, moisture, organic carbon, pH, stable isotopes, radiocarbon age, and thaw strain. We found strong associations among biophysical components but also highly variable soil properties and ecological histories. We developed a conceptual model of the transition pathways and biophysical drivers among ecosystem types. Across sites, fluvial deposition was active from 9820 to 4290 14C YBP, eolian silt and sand deposition prevalent from 3780 to 1890 YBP, and peat accumulation from 5330 YBP to present. Due to flat topography, water impoundment in depressions, groundwater, and ecological feedbacks, ecosystem-driven permafrost has a complex history of repeated aggradation and degradation resulting in highly fragmented landscapes. Recent thermokarst features had ages ranging from 20 to 920 YBP in collapse-scar bogs and from 50 to 250 YBP in collapse-scar fens. Abandoned floodplains with rapid thermokarst provide saturated environments for robust organic accumulation, with mean soil carbon stocks in the top 3 m being similar among thermokarst bogs (133 kg/m2), fens (108 kg/m2) and permafrost plateaus (115 kg/m2). This study contributes needed information on how permafrost dynamics and ground-ice characteristics influence landscape evolution and on the vulnerability of villages built on abandoned floodplains, infrastructure, and military use of training lands in boreal lowlands. Landscape fragmentation, complex palaeoecological histories, high spatial variability, and limited deep sampling of thermokarst features, however, restrict interpretation of how permafrost loss is affecting the soil carbon balance in an area where most permafrost will disappear in this century.

Geosciences doi: 10.3390/geosciences16090354

Authors: Jetnipit Muenjaem Niti Mankhemthong Rattanaporn Fongngern Kritsada Moonpa Weerapan Srichan Wachirachai Sakapa Sarawute Chantraprasert Takonporn Kunpitaktakun Chanin Pattarakamolsen

The Lampang Basin is a Cenozoic rift basin in northern Thailand whose geometry remains poorly constrained because of limited subsurface data. This study applies integrated gravity analysis and 3D gravity inversion to characterize basin geometry, structural segmentation, and subsurface density distributions. Complete Bouguer anomaly data from 1488 gravity stations were analyzed using regional–residual separation, edge-detection filtering, spectral depth estimation, and 2D forward gravity modeling, constrained by geological mapping and available borehole and seismic data. The resulting geological and geophysical constraints were incorporated into 3D geometry and density inversions to construct the first basin-scale 3D gravity inversion model of the Lampang Basin. The results identify four structurally distinct, fault-controlled sub-basins, refining previous gravity-based interpretations of three principal sub-basins. The Western and Central Sub-basins trend predominantly NE–SW, whereas the Eastern Sub-basin is predominantly N–S oriented; the Northeastern Sub-basin has a less well-defined geometry but is bounded by structures supporting a broadly N–S alignment. The 3D inversion indicates a maximum preserved sediment thickness of ~2050 m, with the deepest depocenter within the Central Sub-basin, whereas the broadest depocenter occurs within the Eastern Sub-basin. Gravity anomalies and inversion-derived density distributions further indicate an association between contrasting pre-Cenozoic basement domains on basin segmentation and geometry, including accretionary complexes, volcanic arcs, and forearc basin successions of the Paleo-Tethys subduction margin. Integrated gravity modeling therefore provides regional constraints on the preserved geometry and structural segmentation of Cenozoic intermontane basins where direct subsurface information is spatially limited.

Geosciences doi: 10.3390/geosciences16090353

Authors: Emmanouil Chatziangelis Nikolaos Depountis Konstantinos Nikolakopoulos Nikolaos Sabatakakis

Reliable stability assessment of structurally complex rock masses increasingly relies on advanced remote sensing techniques integrated with detailed geotechnical analysis. This study presents a combined remote geotechnical workflow applied to rock masses surrounding natural cavities, with the study area located in Greece, aiming to evaluate the stability of coupled cavity–slope systems under varying conditions. The methodology combines Unmanned Aerial Vehicle (UAV) photogrammetry and SLAM-based LiDAR surveying to acquire centimetre-scale surface and underground opening data. These datasets are fused into a geometrically consistent three-dimensional representation of the slope–portal–cavity system, enabling improved documentation of slope morphology, internal cave geometry and externally exposed discontinuity patterns. The fused spatial dataset was then used to extract a representative two-dimensional cavity–slope section for plane-strain finite element analysis. The numerical model was formulated as an equivalent-continuum model using the Hoek–Brown failure criterion, with stability assessed through the Shear Strength Reduction technique across multiple scenarios. Overall, the study demonstrates that integrated geotechnical and remote-sensing approaches improve geometric completeness and consistency, enhance reproducibility, and reduce geometry-related uncertainty in scenario-based stability assessments of complex rock masses with natural cavities and underground openings.

Geosciences doi: 10.3390/geosciences16090352

Authors: Jing Yang Dehe Yang Zhima Zeren Chong Xu Yuandong Huang Jianping Huang Hengxin Lu

Shallow landslides triggered by extreme rainfall often occur abruptly and show pronounced spatial clustering. Accurate representation of rainfall conditions is therefore important for event-based landslide hazard assessment. This study investigated shallow landslides triggered by the April 2024 extreme rainfall event in Jiangwan Town, Guangdong Province, China. An event-based landslide inventory, half-hourly GPM IMERG precipitation data, and multiple environmental factors were used for hazard modelling. Three rainfall descriptors were considered: event cumulative rainfall, 21-day cumulative rainfall, and maximum 1 h rainfall. Controlled incremental experiments using Random Forest (RF) were conducted to evaluate the additional predictive information provided by these rainfall descriptors. RF, XGBoost, and an Artificial Neural Network (ANN) were then compared in terms of predictive performance. Incorporating all three rainfall descriptors increased the RF test-set AUC from 0.907 to 0.945. Among the three predefined rainfall descriptors, 21-day cumulative rainfall produced the largest incremental improvement. XGBoost achieved the highest overall predictive performance, with a test-set AUC of 0.971, and was selected for final hazard mapping. The high- and very-high-hazard zones predicted by XGBoost covered 33.2% of the study area and contained 89.7% of the observed landslide samples. These zones were concentrated mainly in the central and northeastern parts of Jiangwan Town. SHAP analysis identified elevation as the most influential predictor, while all three rainfall descriptors ranked among the important predictors. Overall, the results indicate that rainfall information at multiple temporal scales provides complementary predictive information and can improve event-conditioned shallow-landslide hazard assessment.

Geosciences doi: 10.3390/geosciences16090351

Authors: Mingxiao Sun Mahabbat Tursyngazy

The eastern Pre-Caspian Depression and northern margin of the Tarim Basin are two Paleozoic craton-based basins that were impacted by different late Paleozoic collisional systems—the Uralides and the South Tian Shan. A comparative analysis was performed on their Paleozoic petroleum source rocks as part of this research project. This comparison utilized an identical methodological process across both basins. Data on total organic carbon content (TOC), Rock-Eval pyrolysis and vitrinite reflectance (Ro) were obtained from 15 wells (eight in the eastern Pre-Caspian Depression and seven in the Tarim Basin). In addition to these new datasets, published regional databases and sediment accumulation rates calculated at 40 locations were used. The Pre-Caspian source rocks contained TOC values ranging from 1.9 wt% to 6.0 wt% (average = 3.5 wt%) and had hydrogen indices (HI) ranging from 279 to 500 mg hydrocarbons per gram TOC; they were characterized as oil-prone Type II kerogens and were mature to late-mature (Ro = 0.85–1.40%). The Tarim source rocks contained less TOC (range = 1.2–4.8 wt%; average = 2.6 wt%) and had HI values that were generally lower and highly variable (range = 80–350 mg hydrocarbons per gram TOC); they were composed of Type I–II to III kerogens and were significantly more mature than those found in the Pre-Caspian Basin (range = Ro = 0.80–2.00%), with some areas reaching the dry-gas window. Sediment Accumulation Rates (SARs) were approximately equal in magnitude (maximum SARs ranged from 60 to 64 m per million years) but differed in terms of spatial distribution. While SARs were primarily focused along the southern margin of the Tian Shan mountain range in the Tarim Basin, SARs were relatively evenly distributed throughout the intracratonic eastern Pre-Caspian Depression. Therefore, it can be concluded that the type of orogenic system is responsible for determining when source rocks enter the oil and gas windows, providing a transferable methodology for distinguishing oil- from gas-prone fairways within orogen-flanked cratonic basins.

Geosciences doi: 10.3390/geosciences16090350

Authors: Natalia Fernandes Clara Vasconcelos

Inclusive education aims to eliminate barriers to the access, participation, and success of all students. For Deaf students, challenges related to accessibility, communication, and the adaptation of teaching practices to diverse linguistic, cultural, and sensory needs persist. This theoretical article discusses the potential of Nature-Based Learning (NBL) for promoting inclusive educational practices for Deaf students. Drawing on the literature, it examines the foundations of NBL, considers Deaf students’ learning while acknowledging the heterogeneity of this population, and analyses opportunities and challenges associated with nature-based educational experiences. The literature suggests that NBL may support participation, engagement, social interaction, and content understanding through visual, tactile, spatial, embodied, and experiential learning opportunities. However, its inclusive potential depends on linguistic accessibility, adapted resources, teacher preparation, and consideration of individual communication and learning needs. To illustrate how these principles may be translated into practice, the article presents an inclusive geology activity in an outdoor context supported by Portuguese Sign Language. The activity is presented as an illustrative pedagogical proposal rather than an empirically validated intervention. Overall, NBL represents a promising framework for developing more accessible, participatory, and meaningful educational experiences for Deaf and hearing students.

Geosciences doi: 10.3390/geosciences16090349

Authors: Muhammad Haseeb Shoukat Lizardo Reyna-Bowen Anna Klamerus-Iwan

Surface biomass, including litter, organic matter and ground vegetation, plays a very important role in forest ecosystems for regulating water retention and soil erosion. At the global and European temperate forest scale, no bibliometric analysis has previously been conducted, even though the scientific interest has been growing. This bibliometric analysis studied 1189 global and 178 European temperate forest articles retrieved from Scopus from 2005 to 2025 using RStudio (bibliometrix) and VOSviewer. The global output grew at an annual growth rate of almost 20.83%, coinciding with the Paris Agreement 2015 and the European Green Deal 2019 that may have brought scientific attention to climate change, hydrological process, forest ecosystem services and sustainable forest management, leading to the increases, while European research accounted for only 14.9% of global output and was mainly influenced by Mediterranean fire-related research, which limits its direct applicability to central European forest conditions. China and the USA dominated the global research output. Despite being the country with 30% of its area covered with forests, no Polish institution appeared in the top 10 contributors in both the global and European datasets. Thematic analysis showed that infiltration and surface runoff are poorly integrated with forest management and climate change research. Litter and soil organic carbon appeared as an emerging topic in the European Temperate Forest dataset. Three dominant tree species of the central European temperate forest, Scots Pine (Pinus sylvestris L.), Norway Spruce (Picea abies), and European aspen (Populus tremula L.), were each mentioned just once in 178 European publications, indicating the need for species-specific research about water retention and erosion susceptibility and surface runoff. This bibliometric analysis identified the significant species-specific, institutional, and regional knowledge gaps in European temperate forest research, most importantly, for the central European ecosystem and the dominant Polish forest. The study highlighted the limited incorporation of hydrological processes with forest management and climate adaptation strategies. Future research direction should focus on long-term field research analysing biomass changes, water retention and erosion susceptibility in the European temperate forest ecosystem, while promoting stronger international research collaborations.

Geosciences doi: 10.3390/geosciences16090348

Authors: Mohamed A. Khalifa Mohamed M. Ghoneim Mohamed Mahmoud Abu El Hassan Ahmed Anwar El Feky Amr S. Zaky

The Nubian Sandstone succession exposed along the Quseir–Qift Road, Eastern Desert, Egypt, has commonly been treated as a broad sandstone-dominated interval, limiting local stratigraphic resolution. This study establishes a formation-scale lithostratigraphic subdivision of that succession. Field control comprises 18 Global Positioning System (GPS)-referenced localities—15 within the Quseir–Qift corridor and three comparison localities at Wadi Hammamat. Principal measured-section controls, contact localities, and lateral checks were organized into eight composite logs within a 1:25,000 mapping framework. From base to top, the succession comprises the Araba, Abu Thora, Abu Durba, Malha, Bahariya, and Taref formations, with recorded thicknesses of 77.5–84.5 m, 68–72 m, approximately 24 m, approximately 78 m, 37–60 m, and 7–37 m, respectively. Formation boundaries were distinguished from ordinary facies changes by persistent package-scale shifts in lithological association and vertical organization, reproducible stratigraphic position, and traceable contact or marker relationships where exposure allowed. Regional correlation was evaluated only after local differentiation. The observed facies associations are consistent mainly with fluvial systems, with local tidal or shallow-water influence in Araba and Abu Thora and a restricted evaporitic setting in Abu Durba. Because no independent local biostratigraphic or geochronologic ages were obtained, formation ages remain regional, correlation-based assignments and may be diachronous. The framework improves local stratigraphic resolution without proposing new formal units or a definitive regional solution for the Nubian Sandstone.

Geosciences doi: 10.3390/geosciences16090347

Authors: Brittany M. Russo Robert E. Kayen

Rock slope landslide potential, tunnel design, and the engineering of underground spaces critically require an analysis of rock joint orientation and spacing. Joint set measurements are typically determined by hand in the field using a compass–clinometer to measure the orientation of the geologic planes with respect to north and the dip of the plane with respect to the horizontal. Unmanned aerial vehicles (UAVs) can be utilized to capture hundreds of photos to create high-resolution 3D models of a rock outcrop, capturing visible joint set discontinuities on a faceted surface of a triangular irregular network (TIN). Computing methods of facets and facet normals from a point cloud allow for the characterization of discontinuity orientations without the need for manual measurements in the field. However, these methods used to calculate facets and facet normals result in the addition of noise in the dataset, which increases the difficulty of analysis. A two-stage filtering process employing density-based spatial clustering of applications with noise (DBSCAN), and the second derivative of the remaining clusters, removes data that are not representative of a discontinuity within the intact rock mass. Finally, an unsupervised clustering algorithm, K-Means Clustering, is applied to the dataset to extract the dip and dip direction of discontinuities. The methodology used to identify the orthogonal joint sets on a dam spillway demonstrated good performance across all identified joint sets, with the estimated variability in dip and dip direction broadly comparable to that observed in the manual field dataset. This indicates that this newly developed proof-of-concept approach can reliably capture the orientation and variability of orthogonal joint sets from large datasets.

Geosciences doi: 10.3390/geosciences16090346

Authors: Dimitrios Nikolopoulos

This editorial is a part of the Special Issue (SI) “Editorial Board Members’ Collection Series: Natural Hazards” [...]

Geosciences doi: 10.3390/geosciences16090345

Authors: Isabelle Moretti Mathis Diroff Fabien Cubizolle Alejandra Carrillo-Ramirez Sebastien Lacaze

Although uncertainties regarding natural hydrogen (H2) reserves remain high, exploration activity is expanding across several countries. To date, the only active production site uses this resource locally for electricity generation; however, operating companies could target industrial markets where H2 can serve as both an energy source and a chemical feedstock. Surface constraints and proximity to commercial markets will dictate distribution and utilization strategies when alternative options are available. This study introduces a novel tool that integrates surface and subsurface constraints to rank prospective exploration areas, enabling companies to identify opportunities aligned with their specific corporate profiles or business plans. The methodology is applied to western Colombia, a region characterized by many surface constraints and known H2-generating source rocks; H2 surface emanations have also been documented. Western Colombia is structurally divided by north–south mountain ranges (Cordilleras) that severely hinder east–west transportation and contribute to regional energy insecurity. Using a comprehensive data compilation, this study demonstrates how applying different weighting schemes to diverse geographical and geological parameters can optimize site selection. The Medellín area ranks highest if the target is the industrial market.

Geosciences doi: 10.3390/geosciences16090344

Authors: Zhen Wu Manzhong Qin Yuansheng Zhang

The Loess Plateau in China is highly susceptible to frequent landslides and other geological disasters, which have led to substantial losses of natural and human resources and are frequently reported in the news media. Yuzhong County, located east of Lanzhou City, is a mountainous region with considerable development potential. On 7 August 2025, this area experienced a large-scale geological disaster characterized by a compound event involving both landslides and debris flows, resulting in nearly several hundred casualties. With the ongoing urban expansion of Yuzhong County in recent years, the prediction and prevention of geological disasters have become increasingly critical. This study employed three machine learning algorithms—Multiple Logistic Regression (LR), Random Forest (RF), and XGBoost (XG)—to assess landslide susceptibility in Yuzhong County. A total of 169 historical landslide points, supplemented by additional sites identified through field investigations, were compiled, along with 200 non-landslide locations. Multiple environmental factors were incorporated into the models to analyze landslide susceptibility across different areas. Because LR can effectively capture the generalized influence of precipitation variability, it was selected as the primary model for the final susceptibility mapping. To more accurately evaluate the impact of precipitation on landslide occurrence, average seasonal precipitation across the four seasons was used as a predictive factor. To refine the risk assessment at the township level, both raster-based and landslide-unit-based evaluation approaches were adopted. Overlay analyses were then performed by integrating urban infrastructure, population distribution, and predicted landslide hazard zones, while also accounting for the potential influence of extreme precipitation events. The results reveal that the mountainous areas in eastern Mapo Township, southern Xiaokangying Township, southern Xiaguanying Town, and the south-central part of Qingshuiyi Township are high-risk zones prone to group-occurrence landslide disasters.

Geosciences doi: 10.3390/geosciences16080343

Authors: Sen Kong Jie Liu Zhiru Geng Shouchun Wei Chunyi Li Jiehai Cheng

As a key tectonic zone formed by the India–Eurasia collision, the eastern Tibetan Plateau has complex crustal structures and intense tectonic activity. Its crustal stability is closely linked to regional geohazards and the safety of major engineering projects. This study assessed crustal stability using nine multi-source datasets, including terrestrial gravity, Bouguer gravity anomalies, seismic data, active faults, terrain indicators, and annual precipitation. A hybrid weighting framework coupling the Analytic Hierarchy Process (AHP) and CRITIC method was established, and factor analysis was further adopted to cross-verify the rationality of index weights. Moderately unstable and unstable zones appear as alternating bands with distinct linear extensions. These unstable areas are mainly distributed around Jiuquan–Zhangye–Wuwei, Xining–Haidong, Yushu–Garzê, Mianyang, and Chengdu. Statistically, stable, moderately stable, moderately unstable, and unstable zones account for 20.74%, 35.47%, 28.78%, and 15.01%, respectively. The results provide a scientific reference for regional planning and infrastructure site selection in tectonically active regions.

Geosciences doi: 10.3390/geosciences16080342

Authors: Lu Zhou Xinyu Sun Minggang Tang Hong Lou Jian Wang Zhenhan Zhang Jinfeng Feng Haihua Qiu

Deep Cretaceous clastic reservoirs in the Kuqa Depression are major targets for natural gas exploration in the Tarim Basin. Recent exploration of the Yageliemu Formation in the Ketan area has revealed considerable resource potential, although reservoir performance is strongly affected by deep burial, compaction, repeated fluid–rock interaction, and pronounced pore-system heterogeneity. Core descriptions, epoxy-impregnated thin sections, cathodoluminescence, scanning electron microscopy, conventional petrophysical measurements, mercury intrusion capillary pressure, and nuclear magnetic resonance data were integrated to evaluate sedimentary fabric, reservoir-space types, pore-throat characteristics, and diagenetic modification. The succession was deposited mainly in a braided river delta plain setting and is dominated by medium sandstone, pebbly sandstone, and fine conglomerate. Overall reservoir quality is poor, with an average porosity of 3.4% and permeability commonly between 0.01 and 0.5 mD. MICP and NMR data distinguish four pore-structure types. From Type I to Type IV, average displacement pressure rises from 0.89 to 11.02 MPa, whereas median throat radius and movable-fluid porosity decline from 0.17 to 0.01 μm and from 2.00% to 0.72%, respectively. Residual intergranular pores constitute the main storage space, while feldspar- and lithic-fragment-dissolution pores provide additional local storage. Fractures contribute little pore volume but can markedly improve connectivity where they remain open or only weakly cemented. The present reservoir heterogeneity reflects the combined effects of sand-body stacking, sandstone–mudstone arrangement, fault-related fracturing, and multistage diagenesis. The most favorable intervals occur in thick, relatively clean stacked sand bodies where residual pores are preserved, dissolution pores remain connected to the throat network, and fractures have undergone limited late-stage filling.

Geosciences doi: 10.3390/geosciences16080341

Authors: Munkhtsolmon Munkhchuluun Davide Elmo

Rock bolts are the primary ground support mechanism in underground mining. Yet verification of their installation is rarely captured in a spatially precise, retrievable form, leaving operators without an auditable as-built record for regulatory review or post-incident reconstruction. This paper presents an automated rock bolt detection process that closes this documentation gap using dense point clouds from an underground hard rock mine acquired by terrestrial laser scan. The method computes per-point ambient occlusion (AO) on closure plane-sealed chambers using a PCV implementation of the ShadeVIS principle, forms candidates from a multi-scale protrusion field, and segments them by prominence watershed before classifying each candidate with PCA-based geometric descriptors, without machine learning or training data. Installation perpendicularity is applied as a per-detection confidence cue, and detections are reported in confidence tiers that concentrate human review on the ambiguous minority. Validated against a database of 1447 bolts across 20 walls in two areas of an underground mine, the system achieved an overall recall of 83.7%, with human review completing the inventory to 100%. The physics-based design transfers across bolt types and mine geometries through parameter re-tuning rather than retraining, addressing the core limitation of deep learning methods, which require site-specific labelled datasets.

Geosciences doi: 10.3390/geosciences16080340

Authors: Yuxiang Wang Yang Wang Junxing Ren Xuguang Dong Xiaoyang Wang

Bulk compressibility of reservoir rocks can be characterized dynamically or statically, and both vary with burial depth due to increasing temperature and pressure. To quantify these effects, cyclic hydrostatic compression tests are conducted on two reservoir sandstones under confining pressure up to 50 MPa at three temperatures (30 °C, 70 °C, and 110 °C). Experimental results show that static bulk compressibility is consistently larger than dynamic values across all tested conditions. As confining pressure increases, static compressibility decreases more sharply than dynamic compressibility, leading to a gradual reduction in their discrepancy. In contrast, temperature exerts a weaker yet more complex influence. Elevated temperature increases dynamic bulk compressibility, but has opposite effects on static compressibility upon loading versus unloading: it reduces static compressibility upon hydrostatic loading but enhances it upon unloading. This complex temperature dependence is attributed to thermally induced stress, which resists hydrostatic compression during loading but assists decompression during unloading. The influence of thermal stress is more pronounced at low confining pressures. These findings highlight that temperature not only alters the magnitude of static compressibility but also introduces path-dependent asymmetry between loading and unloading, which has important implications for reservoir geomechanics, subsidence prediction, and production-induced compaction in high-temperature environments.

Geosciences doi: 10.3390/geosciences16080339

Authors: Khaled Haddad Surendra Shrestha

The geosciences have witnessed a rapid expansion of analytical methods, from classical linear models to geostatistics and modern machine learning. However, no single resource compares a curated selection of these methods systematically while also providing reproducible code. This reproducibility-driven review evaluates seven analytical techniques applied to three simulated geoscience datasets: spatial points, time series, and a spatio-temporal grid. Methods were selected based on their availability in R to ensure transparency and accessibility. This paper serves as a historical review, a comparative benchmarking study, and a practical teaching resource with fully reproducible R code. The methods include linear regression, ARIMAX, ordinary kriging, regression-kriging, random forest, feed-forward neural networks, and BART. For spatial prediction, when evaluated against the true field, linear regression achieved the lowest mean RMSE (1.94 ± 0.23), followed by random forest (2.13 ± 0.23) and ordinary kriging (2.20 ± 0.26)—highlighting the importance of consistent out-of-sample validation. Regression-kriging performed similarly to ordinary kriging (2.22 ± 0.26). For time series, a feed-forward neural network (0.37 ± 0.09) substantially outperformed seasonal ARIMAX (1.90 ± 1.30). For spatio-temporal prediction, random forest and BART performed indistinguishably (0.534 ± 0.004 vs. 0.543 ± 0.004). A practical decision guide, grounded in these empirical results, summarises method selection based on sample size, data type, and research goal—whether inference, prediction, or uncertainty quantification. All code is open and reproducible, providing a template for future method comparisons.

Geosciences doi: 10.3390/geosciences16080338

Authors: Yuanyin Zhang Zhongkai Bai Dayong Li Xintao Wang

An accurate prediction of gypsum-salt cap rocks is crucial for safe drilling and efficient development of subsalt hydrocarbons in the Tarim Basin. However, due to the complex lithological assemblages within the Middle Cambrian sequences, the P-impedance of gypsum severely overlaps with that of the background carbonate rocks, making conventional seismic prediction based on a single impedance threshold inadequate. To address this issue, this paper proposes a multi-parameter coupling while-drilling prediction method that integrates seismic data, drilling parameters and geochemical logging. First, pre-stack P-impedance inversion is performed on amplitude-preserved seismic data to macroscopically delineate the depth interval of gypsum-salt development. Second, a weighted synthetic change-rate model incorporating drilling time (DT), weight on bit (WOB), and outlet conductivity is constructed to dynamically calibrate the top interface of the gypsum-salt layer while drilling. Finally, within the constrained depth interval, X-ray fluorescence (XRF) elemental inversion of cuttings is used to quantitatively calculate the contents of clay, dolomite, gypsum and calcite, achieving fine-scale lithofacies identification at the sublayer level. An empirical application to Well XSC1 in the Keping fault-uplift, Tarim Basin, demonstrates that compared with the conventional single P-impedance threshold method, the proposed approach effectively distinguishes gypsum, salt and carbonate wall rocks, and significantly reduces the prediction errors of individual salt beds and gypsum sublayers. Specifically, the mean absolute error (MAE) of total gypsum-salt content decreases from 24.56% to 13.73% (a reduction of 44.1%), the bias drops from 2.45% to 0.31%, and the root mean square error (RMSE) decreases from 33.63% to 21.55%. At a 1% content threshold, the F1 score for gypsum-salt identification increases from 0.63 to 0.82; the absolute depth error of the top and bottom interfaces is reduced by approximately 70%, and the relative thickness error shrinks from ±40% to within ±10%. Transferability of this multi-parameter coupling strategy to other salt-bearing basins in central-western China remains unvalidated and requires future validation and testing.

Geosciences doi: 10.3390/geosciences16080337

Authors: Raquel Arcoverde Vila Nova Rodrigo Mikosz Gonçalves Susana Costas Filipe Galiforni-Silva Leandro Ponsoni Paulo Henrique Gomes de Oliveira Sousa

This study aimed to evaluate and quantify the environmental impacts generated by anthropogenic actions on coastal dunes globally using bibliometric data, while concurrently identifying human impacts in a local context on the Brazilian semi-arid coast. A systematic review identified 897 relevant publications from a final sample of 1838 works, revealing an increasing trend in global research, peaking in 2018. Geographically, the United States (141), Italy (95), and Spain (79) lead the field, with Brazil contributing 46 publications. The global overview highlights urbanization (217 studies) and tourism (193 studies) as the most frequent impact factors, contrasting with common mitigation measures like dune stabilization with vegetation (112 studies) and beach nourishment (74 studies). Critically, 11 studies reported that management actions, particularly stabilization without considering native flora, led to problems with invasive plants. A significant research gap was identified due to the absence of literature on wind farms, typically located in transgressive dune systems. The local case study in Ceará state confirms dynamics consistent with global trends, where intense exploitation results in management failures; quantitative temporal analysis (2015–2023) demonstrated a dramatic 86.76% loss of dune area in Fortim and a 4.24 km2 loss in Jijoca de Jericoacoara. Findings suggest that, in the Ceará case study, restricting access, promoting community participation, and relocating infrastructure to more appropriate areas may help mitigate human impacts. In addition to identifying potential research gaps, this integration of global and local analysis approaches can contribute to evidence-based coastal dune management adapted to local conditions.

Geosciences doi: 10.3390/geosciences16080336

Authors: Victor Corchete

The first electrical conductivity model determined beneath the InSight landing site is revisited in this study by performing a careful selection of magnetic records from the IFG dataset. This conductivity model is recalculated for the crust and the uppermost mantle (0–182 km depth), considering the data provided by this careful selection. In general, the present model shows a good agreement with synthetic models and other models calculated from magnetic data. In the present model, the conductivity of the crust is 0.0007 S/m, and the conductivity for the uppermost mantle coincides with that determined in the former paper. The crustal conductivity has been calculated for the first time beneath the InSight landing site. Better knowledge can be achieved when more accurate magnetic data are available.

Geosciences doi: 10.3390/geosciences16080335

Authors: Mayahuel Ortega-Avilés Dolores Tenorio-Castilleros Noemi Castillo-Tejero José G. Miranda-Hernández

The “Los Escudos” mural at the Late Postclassic site known as Tehuacán–Ndachjian in Puebla, Mexico, is relatively unknown within Mexico due to there being limited access to the site, which is situated underground on a mountain. This study describes the first unique opportunity to analyse mural painting samples on mud plaster from this archaeological site. Small, pigmented samples were analysed using optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The compositional and structural characterisation of the samples revealed a stratigraphic composition without a lime plaster layer in addition to the presence of minerals, such as hematite, goethite, palygorskite, gypsum, and feldspars. These findings support the conclusion that the “tempera on earth” pictorial technique with mineral pigments was used to create the mural. The overall results provide valuable data concerning the types of materials and techniques that were used and serve as a reference for conservators in addressing preservation, conservation, and restoration issues for mural paintings on mud plaster. Furthermore, the study enhances understanding of ancient painting techniques on mud plaster and the technological advances that were developed by pre-Hispanic cultures in Mexico.

Geosciences doi: 10.3390/geosciences16080334

Authors: Wei Tian Lianfu Mei Hesheng Shi Yu Shu Hailun Liu Baomin Zhang Le Zhu

The Pearl River Mouth Basin (PRMB) is a significant offshore petroleum basin located in the northern South China Sea, characterized by its complex structural features and well-developed boundary faults. Despite its importance, several critical questions regarding fault growth, evolution models, and genesis mechanisms remain unresolved. This study aims to address these gaps by discussing the evolution of the boundary fault system and its associated stratigraphic record. This study utilizes high-resolution 3D seismic reflection data interpretation and fault displacement profiles to investigate the Zhu I depression, the largest hydrocarbon-bearing depression in the northern rifted zone of the PRMB. The findings indicate that the syn-rift growth of boundary faults within the Zhu I depression exhibits three distinct patterns, along-strike linkage, transverse linkage, and oblique linkage, which are formed under the action of the pre-existing basement fault systems. These patterns describe how individual fault segments connect and evolve during the rifting process, influencing the overall structural development of the basin and hydrocarbon accumulation. Although transverse linkage includes three development stages, consistent with previous studies, these stages are isolated normal faults, overlapping faults, and hard linkage. The study reveals a unique example of how transfer faults within a relay ramp connect the normal boundary faults on both sides. The break progression of the relay ramp can also be classified into three stages, similar to the transverse linkage. This study proposes a new approach, through the inversion of fault evolution by sequence migration, for the reconstruction of fault connection processes and complex fault linkage models developed in southern China and similar areas worldwide.

Geosciences doi: 10.3390/geosciences16080333

Authors: Gemma Aiello

Tsunami hazards in the Bay of Naples are primarily driven by submarine landslides, intense seismic activity, and volcanic phenomena from nearby systems like Vesuvius and the Campi Flegrei caldera. While localized historical tsunamis have occurred, they are generally rare events. Key tsunami sources include submarine landslides, volcanic eruptions, and seismicity. In this paper we provide a review of the tsunamis in Naples Bay within a general framework of Mediterranean tsunamis based on a literature review. Underwater avalanches, particularly around the steep slopes of the Dohrn Canyon and Ischia, are considered a primary localized threat. Scientific models indicate that a major collapse (like past events like the Ischia debris avalanche) could generate significant waves that could cross the bay in minutes. Explosive eruptions where magma meets seawater (such as PDCs—pyroclastic density currents) can displace water violently. This was famously documented during the AD 79 eruption of Mount Vesuvius, which created submarine ash fans and tsunami waves in the gulf. Earthquakes related to bradyseism in the Campi Flegrei or regional faults can also trigger sea level oscillations or localized tidal waves. Among the historical modeled events, we focus on the A.D. 79 eruption and on the 1343 Naples tsunami. The numerical simulations are revised. Depending on the source, the modeled waves vary from minor oscillations to heights of up to 6 m in canyon areas or over 20 m in nearby islands like Ischia.

Geosciences doi: 10.3390/geosciences16080332

Authors: Fei Teng Guoying Li Jianjun Jia Yuanhe Tang Wendi Guo Leon Bagas Shuai Yang Xiao Li Fei Bian Yongbao Gao Liyong Wei

The Pangjiahe Au deposit is the largest gold deposit in the Fengxian district of the West Qinling Orogen (WQO), Central China. However, the timing of gold mineralisation and its relationship to the regional metallogenic evolution of the WQO remain poorly constrained. In this study, detailed geological investigations, TIMA mineralogical analysis, in situ Rb–Sr dating of hydrothermal sericite, and in situ Fe–S isotope analyses of auriferous pyrite were conducted to constrain the timing of mineralisation, the evolution of ore-forming components, and the regional metallogenic significance of the Pangjiahe Au deposit. Hydrothermal sericite intimately associated with gold mineralisation yields an in situ Rb–Sr isochron age of 207.6 ± 3.1 Ma, providing the first direct age constraint on gold mineralisation at Pangjiahe. This age is consistent with those reported for the nearby Huayagou Au deposit and several other major gold deposits in the West Qinling Orogen, supporting a regionally extensive Late Triassic gold mineralisation event. The Pangjiahe Au deposit shares closer geological, geochronological, and isotopic affinities with the Huayagou Au deposit and the major Au deposits of the Middle Qinling in Gansu than with the traditionally correlated Au deposits of the North Qinling. These results provide new constraints on the regional metallogenic relationship between the Fengtai Basin and the Middle Qinling metallogenic system, contributing to a better understanding of Late Triassic gold mineralisation in the West Qinling Orogen.

Geosciences doi: 10.3390/geosciences16080331

Authors: Muhammad Qasim

The Baraul Banda Formation preserves an important Paleocene–Eocene sedimentary record within the western Kohistan–Ladakh Arc (KLA) and provides new constraints on sediment provenance and tectonic evolution during the final stages of Neo-Tethyan closure. This study integrates stratigraphic observations, detrital zircon U-Pb geochronology, and quantitative provenance analyses to investigate sediment sources and basin development within the western India–Eurasia collision zone. The formation comprises a thick marine siliciclastic succession of conglomerate, sandstone, siltstone, mudstone, and slate deposited in a tectonically active forearc basin. Detrital zircon age spectra are dominated by Mesozoic–Cenozoic populations (48%) with major peaks at ~57–61 Ma, ~70 Ma, ~85–90 Ma, and ~114–115 Ma, accompanied by subordinate Neoproterozoic, Mesoproterozoic, Paleoproterozoic, and minor Archean populations. These age components closely resemble those of the KLA, Karakoram Block, and Lhasa Block. Statistical provenance analyses indicate the strongest affinity with Eurasian arc-related terranes and contemporaneous forearc basin deposits of the Tar and Indus groups, whereas affinity with Indian Plate sources is minor. The provenance record indicates that sediment supply was dominated by erosion of the KLA and the adjacent Karakoram–Lhasa continental margin, with only minor recycled contributions from Indian-derived sources. The youngest zircon populations constrain deposition to the Paleocene–Early Eocene and record rapid erosion of active arc terranes immediately prior to the India–KLA collision. Placed within the regional magmatic chronology, these results support initiation of the KLA by ca. 155 Ma, Late Cretaceous amalgamation with the Karakoram–Lhasa margin at ca. 80–70 Ma, and subsequent collision with India at ca. 60–55 Ma. The KLA therefore remained an active pre-India-collision arc system for approximately 95–100 Myr, whereas collision-related magmatism continued until ca. 40 Ma, extending its complete magmatic history to approximately 115 Myr.

Geosciences doi: 10.3390/geosciences16080330

Authors: Jian Meng Jiawen Liu Kegang Li Tianlong Zhou Han Zhou

Determining the shear strength parameters of granular materials in high waste rock dump slopes is essential for reliable slope stability analysis. In this study, dump materials were sampled from six benches (elevations 2800–2950 m) of an open-pit mine dump slope, and in situ density tests, gradation analyses, and large-scale consolidated drained (CD) triaxial tests were performed. Two PFC2D slope models—one with uniform (spatially averaged) parameters and one with elevation-dependent (layered) parameters—were then established to quantify how spatial heterogeneity affects stability predictions. The results show pronounced vertical heterogeneity: density, porosity, gradation, and shear strength parameters vary systematically among benches, reflecting the combined effects of compaction history and particle segregation during dumping. All specimens exhibited strain hardening and continuous shear contraction, and specimens with a denser, better-graded structure showed higher strength and lower compressibility. The layered model yields a higher factor of safety and shallower, bench-scale slip surfaces, whereas the uniform model underestimates stability and misplaces the critical slip zones. These findings demonstrate that elevation-dependent parameter assignment better represents the heterogeneous failure mechanism of high dump slopes and should be preferred over uniform parameterization in stability analyses of similar waste rock dumps.

Geosciences doi: 10.3390/geosciences16080329

Authors: Lu Zhou Xinru Zheng Hong Lou Minggang Tang Jian Wang Fangjie Hu Xiaolong Sun Haihua Qiu

The deep to ultra-deep sandstone reservoirs of the Cretaceous Bashijiqike Formation in the Kelasu structural belt of the Kuqa Depression exhibit strong heterogeneity. This study integrates single-well stress calculation, image log fracture interpretation, thin-section petrographic analysis, and porosity–permeability testing to compare stress, fracture, and reservoir characteristics across the Dabei–Bozi cross-section. The results show that the northern stress release zone is characterized by low SH (98 to 148 MPa) and E (9220 to 23,420 MPa), indicating weak cumulative stress, low effective fracture density (0.09 fractures/m), and primary-pore dominated reservoirs. The central stress transition zone has progressively increasing SH (136 to 187 MPa) and E (27,450 to 33,210 MPa) from north to south, indicating strong cumulative stress, high effective fracture density (0.31 fractures/m), and mixed primary–secondary pore-fracture reservoirs. The southern stress accumulation zone shows increasing SH but decreasing E to the south, indicating that the late-stage high stress results in low effective fracture density (0.08 fractures/m) and preserving primary pores. These results demonstrate that reservoir quality is governed by the cumulative effect of the stress field, rather than by present-day stress or peak paleo-stress alone. This reservoir distribution model could provide a theoretical basis for reservoir prediction in the foreland basin.

Geosciences doi: 10.3390/geosciences16080328

Authors: Spencer G. Lucas

Recognizing a trace fossil as a record of organism–substrate interaction is well agreed upon, but some organisms and some interactions are not considered by some workers to be tracemakers or to have produced trace fossils. This is particularly the case with sedimentary structures created or modified by plants and micro-organisms. Plant-made structures that some workers have identified as trace fossils are phytoliths, leaf galls, borings/corrosion structures and rhizoliths. Only borings/corrosion structures and rhizoliths are generally agreed to be trace fossils. Phytoliths are not trace fossils, and most workers do not consider leaf galls to be traces, though that conclusion is open to question. Microbialites (both stromatolites and microbially induced sedimentary structures [MISS]) are not generally regarded as trace fossils, but identification of them as trace fossils has increased recently. The ichnotaxonomy of trace fossils made by plants and MISS needs to be regulated by the Botanical and Prokaryote Codes of Nomenclature. The specific recognition of ichnofossils and the procedures for their ichnotaxonomy need to be spelled out in those codes, much as they have been for animal trace fossils in the Zoological Code. Studies of modern roots and of rhizoliths provide a robust ichnotaxobase for their ichnotaxonomy, including shape, surface texture, internal structures, size, branching, orientation and substrate. Using that ichnotaxobase, a new ichnotaxon, Syrinxichnus tanneri igen. nov and isp. nov., is proposed for some Triassic rhizoliths.

Geosciences doi: 10.3390/geosciences16080327

Authors: Kangkang Li Huan Yu Han Wang Shirong Hu Jianan Li Chengjiang Deng Yunfeng Gao

Landslide susceptibility mapping in alpine regions with limited data has two persistent obstacles: too few recorded landslide cases and the questionable reliability of non-landslide samples. We address these issues with a hybrid generative framework—a Variational Autoencoder (VAE) performs latent-space interpolation to produce additional positive samples, while a Conditional Diffusion Model (CDM) generates counterfactual negative samples. To validate generation quality, we used Principal Component Analysis (PCA) scatterplots, convex hull containment analysis, and covariance structure checks. The generated samples were then evaluated across five classifiers (Logistic Regression (LR), Random Forest (RF), Support Vector Machine (SVM), eXtreme Gradient Boosting (XGBoost), and The Convolutional Neural Network-Transformer-Long Short-Term Memory-Graph Convolutional Network (CTLGNet)). VAE-CDM consistently outperformed the original dataset, Synthetic Minority Over-sampling Technique (SMOTE), and Conditional Tabular Generative Adversarial Network (CTGAN), with XGBoost achieving the best results—Area Under the Curve (AUC) of 0.9337, recall of 0.91, and F1 of 0.87. DeLong’s test confirmed the AUC gain was statistically significant (p = 0.043). After augmentation, the very-high-susceptibility capture rate rose from 68.5% to 89.4%, while cumulative capture curves reflected a 4.9% improvement in spatial targeting efficiency. Shapley Additive Explanations (SHAP) analysis highlighted distance to roads, elevation, and the Freeze-Thaw Index (FTI) as the dominant controlling factors. Application to Southeastern Xizang shows the framework offers a viable pathway for susceptibility mapping in data-limited environments, although the generated samples show moderate diversity reduction (0.53) due to the interpolation-based generation strategy.

Geosciences doi: 10.3390/geosciences16080326

Authors: Abdullah Al Mashani Ram Raj Mathur Asaad Al Hatmi Said Al Awaed Luay Rashan

Hashir Hill, also known as Gravity Hill or magnetic hill in Salalah, Oman, is an iconic landmark where vehicles appear to roll uphill on their own. This unusual effect has drawn scientific interest for years. In this study, topographic and gravity measurements were conducted to explore the causes of this phenomenon. Measurements with a Topcon OS-105 compact total station showed that the road actually slopes downward by about 10.5 m over 350 m. Gravity readings from a Scintrex CG-5 gravimeter showed a gradual increase of about 3.17 mGal, which aligns with the free-air gravity correction for the elevation model. No gravity anomalies were found along the route, which suggests the area is in isostatic balance. A physical analysis employing algebraic inequalities related to gravitational potential energy and Newtonian gravity was involved to validate the findings. The results demonstrate that the perceived uphill movement at Hashir Hill is an optical illusion arising from the local landscape’s visual features, rather than from any unusual physical forces.

Geosciences doi: 10.3390/geosciences16080325

Authors: Thiago Bazzan Camilo Daleles Rennó Elisabete Weber Reckziegel Laurindo Antonio Guasselli Carina Cristiane Korb

Open-water mapping of flooded areas using multispectral remote sensing still presents significant challenges, particularly in urban environments, where high spectral mixing leads to substantial commission and omission errors in water classifications. This study proposes FLOODISI (Flood Detection Integrating Spectral Water Indices), a framework that integrates multiple spectral water indices through adaptive thresholding to generate an Integrated Water Map (IWM). The method was applied to Landsat-8/OLI imagery to map an extreme flood event in southern Brazil. The approach evaluates 12 spectral indices and iteratively adjusts threshold values to minimize false positives while preserving true positives. The results indicate that the Normalized Difference Flood Index (NDFI2), using adaptive thresholding, achieved the best individual performance, with an overall accuracy of 91.8%, whereas the IWM increased this value to 93.5%, substantially reducing omission errors and improving open-water detection in urban areas. In comparison, the Random Forest classification achieved an overall accuracy of 95.0%, but exhibited similar precision and specificity, with a slight increase in commission errors and a modest reduction in omission errors relative to the IWM. In general, the integration of multiple spectral indices with adaptive thresholds through FLOODISI improved the robustness of open-water detection by reducing the dependence on individual spectral indices and providing a scalable, reproducible, and computationally efficient solution for rapid open-water mapping of flooded areas.

Geosciences doi: 10.3390/geosciences16080324

Authors: Osareni C. Ogiesoba Fritz C. Palacios

Geomechanical properties of rock are essential components in designing hydraulic fracturing procedures. Although ultrasonic measurement methods are usually utilized to obtain static geomechanical properties of rocks in the laboratory, they are limited to borehole locations. To obtain spatial distribution of these properties, a 3D prestack seismic inversion process is employed to derive them dynamically. However, 3D prestack seismic datasets are less readily available compared to 3D poststack seismic. We present a methodology that integrates 3D poststack seismic and wireline log data using a machine learning workflow to compute the dynamic geomechanical properties, namely Young’s modulus (E), Mu-Rho (MR), and brittleness (BRI) volumes, and generate crossplots to characterize the Salt Creek carbonate reservoir in the Midland Basin, Kent County, Texas. Our results show that: (1) Based on the comparison of seismically (dynamically) derived E and BRI maps with litho-facies maps, the zones with the highest porosity (oolites) are characterized by low E and low BRI. (2) Each of these properties is linearly related to the photoelectric factor (PEF) log, which can indicate porosity and calcite richness within a mixed carbonate–siliciclastic system. (3) In a mixed carbonate and siliciclastic system, geomechanical properties, especially E, can be used to identify rigid rock layers within the reservoir and deduce possible lithologies. Finally, when prestack seismic data are unavailable, our workflow offers a quick and inexpensive method to generate dynamic geomechanical property maps to characterize hydrocarbon reservoirs using poststack seismic data and well logs.

Geosciences doi: 10.3390/geosciences16080323

Authors: Yerkebulan Bekishev Marzhan Rakhymberdina Eugene Levin Roman Shults Zhanna Assylkhanova

Rare metal exploration increasingly relies on the integration of heterogeneous geological datasets and advanced analytical methods to improve the efficiency and reliability of mineral prospecting. This study presents the development of a web-based Geographic Information System, Geospatial Information System for Optimized Rare Metal Exploration in Eastern Kazakhstan (GISORMEK), using the central part of the Kalba–Narym rare-metal belt (Eastern Kazakhstan) as a case study. A comprehensive geospatial database was developed through the digitization of archival geological maps and the integration of geological, geochemical, tectonic, geophysical, geomorphological, and mineral occurrence datasets. To complement historical mapping data, Landsat-8 multispectral imagery was incorporated to improve lithological discrimination and identify hydrothermal alteration zones. Two remote sensing techniques were applied: Principal Component Analysis (PCA) for lithological mapping and enhancement of geological features, and band ratio (BR) analysis for the calculation of geological spectral indices, including the iron oxide index and the hydroxyl-bearing (Al–OH) mineral index. The resulting spectral indices were subsequently integrated to generate a predictive hydrothermal alteration map. GISORMEK integrates historical and contemporary datasets within a unified web-GIS framework, ensuring spatial consistency, reproducibility, and accessibility. The proposed framework enhances the interpretation of the mineralization potential of the Kalba–Narym region and provides geospatial platform for supporting rare metal exploration and future mineral prospectivity assessments.

Geosciences doi: 10.3390/geosciences16080322

Authors: Thomas Wolfert Alin Mihu-Pintilie Cristian Constantin Stoleriu Vasile Jitariu

The Lacul fără nume landslide dam in the Vrancea Mountains (Romania) represents a unique example of a dynamic landslide dam system characterized by recurrent damming–breaching cycles. Through the combined use of remote sensing, field investigations, and historical reconstruction, eight such cycles were documented over a period of 49 years. To the best of current knowledge, this is one of the few documented landslide dams reported in the scientific literature that exhibits frequent damming–breaching episodes involving repeated dam failure, renewed slope instability, and subsequent re-damming with renewed lake impoundment over comparatively short timescales. The observed persistence and spatial extent of the associated lake are highly variable, ranging from 12 days to almost 10 years and from 23,920 m2 to 82,610 m2, respectively. Antecedent precipitation was frequently elevated prior to lake state transitions, but a seasonally constrained Monte Carlo analysis showed no significant departure from the climatic background, while numerous intense rainfall periods occurred without documented transitions. Similarly, no systematic temporal association was identified between recurrent lake state transitions and regional seismicity, although the initial dam formation coincided with the 1977 Mw 7.4 Vrancea earthquake. These findings suggest that precipitation conditions and seismicity alone cannot explain the recurrent damming and drainage, which likely result from interactions between hydrometeorological forcing, geomorphic processes, and human influences. Taken together, the results and the proposed conceptual model demonstrate that debris-flow-generated landslide dams can evolve into persistent and dynamic geomorphic systems capable of posing recurring hazards over multiple decades.

Geosciences doi: 10.3390/geosciences16080321

Authors: Yan Zhang Su He Miaojun Sun Bohan Zhou Mengfen Shen Honglei Sun

Seismic liquefaction poses a significant threat to infrastructure and human safety, making accurate regional-scale hazard assessment essential for effective disaster mitigation. This study systematically compares simple kriging (SK), ordinary kriging (OK), and sequential Gaussian simulation (SGS) for liquefaction potential mapping using a case study of the Chi-Chi earthquake. Results show that among the eight theoretical semivariogram models, the exponential model was identified as the optimal semivariogram model, showing the best fit and the lowest validation errors. SK and OK yield nearly identical LPI estimates with high accuracy and low computational cost, but oversmooth high-risk zones and underestimate spatial uncertainty. In contrast, SGS captures spatial heterogeneity and extreme values, with variance and coefficient of variation maps revealing higher and more heterogeneous uncertainties, which offers a more comprehensive basis for probabilistic risk assessment. However, these advantages came at a substantially higher computational cost. The choice of method should therefore depend on the engineering objective: kriging for rapid, large-scale trend estimation, and SGS for detailed probabilistic risk evaluation where capturing extreme values and uncertainty is critical.

Geosciences doi: 10.3390/geosciences16080320

Authors: Károly Németh Marilena Cozzolino António Vieira

In recent years, research in Geoheritage, Geoparks, and Geotourism has significantly increased, underlining their vital roles in advancing scientific knowledge, conserving the environment, and safeguarding human culture. By exploring the intrinsic value of geological and geomorphological sites as records of Earth’s history and important scientific resources, we seek to enhance appreciation for these landscapes. This Special Issue provided a platform for interdisciplinary exploration and dialogue, addressing the complexities of geoheritage research and offering insights into the conservation, management, and promotion of geological features and landforms. It includes studies on the conceptual foundations for establishing and managing geoparks, as well as research on the evolving field of geotourism and its contribution to sustainable development. A total of 10 papers have been accepted, covering a diverse range of topics and emphasizing the current prominence of geoheritage research within the geosciences.

Geosciences doi: 10.3390/geosciences16080319

Authors: Zharasbek Baishemirov Galina Reshetova Aisha Abobakir Kadrzhan Shiyapov

The spring floods that occurred in 2024 in western and northern Kazakhstan caused extensive damage. Our understanding of runoff formation processes under frozen-soil conditions remains limited. In this study, we apply a coupled hydrothermal model as a case study to explicitly simulate vertical heat and water transport, phase transitions, snow dynamics, and reduced infiltration capacity due to cryogenic pore blockage (ice-filled pores). The model is based on regular meteorological data from 65 stations in five regions covering the full hydrological cycle (August–May) of 2021 and 2024. A multilevel diagnostic check showed that soil temperature is reproduced with a median R2 of 0.962 and NSE of 0.888, the frozen/thawed surface condition corresponds to WMO (World Meteorological Organization) standards on approximately 91% of days, and water balance agreement reaches 86.2% (56 out of 65 stations). The model reflects the regional variability of the 2024 flood. In the northern regions (Kostanay, North Kazakhstan), snowfall was above average, and modeled runoff increased compared to 2021 (for example, at the Sergeevka station, it increased by a factor of four). In the western regions, the trends were mixed: the strongest relative increase in runoff was recorded in the Atyrau region (+119%), whilst in the West Kazakhstan region, the increase was more modest (+19%), and in the Aktobe region, runoff increased by 60%. The key mechanism—the time lag between rapid snowmelt and delayed soil thaw—is clearly evident: peaks in snowmelt occur when the soil remains frozen, infiltration capacity decreases, and the runoff potential index (RPI) exceeds 1 for extended periods. Although the model does not simulate the river channel, its ability to diagnose runoff generation conditions at the slope scale offers a diagnostic framework for identifying runoff-conducive conditions in regions with limited data, rather than a physically validated tool for flood-prone area identification. The results show that the 2024 flood period was characterized by abnormally high water inflow and hydrothermal conditions consistent with a temporal mismatch between water supply and the recovery of soil infiltration capacity. Because the RPI is a diagnostic indicator constructed from water input and infiltration capacity, these results should be interpreted as evidence of conditions conducive to runoff generation rather than as an independent causal verification of the flood mechanism.

Geosciences doi: 10.3390/geosciences16080318

Authors: Zhipeng Huan Yingchang Cao Wei Ju Ziwei Qian Ke Xu Penglin Zheng Zhou Xie Mingjin Cai Ruidong Liu

Ultra-deep Ordovician carbonates in the Tarim Basin are a major target for oil and gas exploration in China. Localized overpressure, however, creates substantial well-control risks and impairs drilling safety and exploration performance. This study investigates the Fudong Block of the Fuman Oilfield using drilling, seismic, and well-test data. We develop a high-resolution, layer-specific formation-pressure prediction workflow that integrates well and seismic data through a stress–fracture-pressure framework. The workflow combines geomechanical modeling, prediction of the in situ stress field and fracture distribution, stress-fracture matching, Biot-theory-based pressure prediction, and iterative calibration against drilling observations. The results show that: (1) overpressure is concentrated near secondary faults, branch faults, and NW-trending faults. It is jointly controlled by tectonic compression, pressure retention within fracture–vug bodies, and fluid charging. Multiple vertically separated pressure systems are common, and their marked heterogeneity is closely related to secondary-fault development and fracture–vug connectivity; (2) drilling disturbance can generate apparent overpressure and lead to erroneous pressure interpretation. Overpressured wells commonly exhibit a kick followed by lost circulation or simultaneous kick and loss. Drilling-fluid invasion into confined fracture–vug bodies causes pressure buildup; and (3) formation pressure is a key parameter in integrated geological and engineering sweet-spot evaluation and is closely linked to wellbore stability. Field applications confirm the accuracy of the proposed workflow. The method strengthens integrated geology-engineering evaluation and provides a practical basis for the safe and efficient development of ultra-deep carbonate reservoirs.

Geosciences doi: 10.3390/geosciences16080317

Authors: Sara Istekova Alexandr Logvinenko Daniyar Kairov Yernar Narimanov Nurbek Shamiyev Raushan Temirkhanova Nurastana Slambek

This paper presents findings from a comprehensive assessment aimed at identifying deep geological storage formations suitable for the secure isolation of chemically active gases, including anthropogenic CO2. Although Kazakhstan currently lacks operational industrial-scale CO2 storage sites, high annual emissions exceeding 2 million tonnes are concentrated in its southern region, specifically Almaty city and the surrounding Almaty Region. Despite this pressing need, the precise location, availability, and capacity of potential storage sites in this area remain poorly understood. By synthesizing legacy geological, geophysical, and hydrogeological datasets compiled within the eastern Ili Depression, this study evaluates regional deep saline aquifers for potential CO2 geological storage under favorable techno-economic conditions. It must be clearly emphasized that this study focuses exclusively on deep groundwater aquifers (saline aquifers). Leveraging historical seismic, drilling, and well-logging data originally acquired for petroleum and water resource exploration, we constrain the stratigraphic architecture and structural framework of prospective storage units. The lithostratigraphic framework of the sedimentary cover in the Ili Basin is established, identifying key reservoir intervals and effective sealing formations. The results indicate that the eastern Ili Depression offers highly favorable conditions for geologic storage, with Permian, Triassic, and Jurassic sedimentary successions reaching thicknesses of up to 1200 m. Reservoir intervals are identified across major stratigraphic units, with potential storage formations accounting for up to 60% of the stratigraphic volume. Specifically, the Miocene–Paleogene and Jurassic intervals host sandstone reservoirs exceeding 10 m in thickness, with porosities reaching up to 30%. Upper Jurassic clayey successions function as effective intraformational seals for Middle Jurassic reservoirs, while Upper Cretaceous clay sequences provide regional caprock integrity for the overlying Neogene–Paleogene sandy intervals. These geological settings satisfy rigorous containment criteria required for secure gas sequestration. These insights into the deep architecture of the Ili Depression elucidate key geological controls governing prospective storage sites, paving the way for future carbon capture and storage (CCS) initiatives in one of Kazakhstan’s most vital economic regions.

Geosciences doi: 10.3390/geosciences16080316

Authors: Wei Yu Jiao Wang Li Gong Jie Chen

The genesis of authigenic clay minerals in tight sandstones fundamentally controls reservoir quality and micro-pore evolution. This study investigates the differential formation mechanisms of authigenic chlorite and kaolinite and their modulating effects on pore systems in the Chang-8 Member tight sandstones, Ordos Basin. Thin-section petrography, X-ray diffraction, scanning electron microscopy, and high-pressure mercury injection were utilized to quantify mineralogical and petrophysical characteristics. Results show chlorite (averaging 4.8%) and kaolinite (averaging 1.6%) are the dominant authigenic clay minerals with distinct spatiotemporal distributions. Chlorite nucleated as pore linings during early diagenesis under alkaline, oligohaline to mesohaline conditions driven by volcanic material hydration. Conversely, kaolinite precipitated as pore-filling during mid-to-late diagenesis (80–120 °C), driven by organic acid pulses from underlying source rocks causing feldspar dissolution. We conclude that early chlorite linings constructively preserve primary porosity by mechanically resisting compaction and chemically inhibiting quartz cementation, despite narrowing pore throats. Meanwhile, kaolinite acts as a pore-type modulator, restructuring macro-pores into micro-intercrystalline pores, which significantly impairs permeability only when its proportion crosses a critical threshold. The diagenetic fluid transition from alkaline to acidic ultimately dictates this mineralogical succession and subsequent reservoir heterogeneity.

Geosciences doi: 10.3390/geosciences16080315

Authors: Marina A. Mizernaya Saltanat S. Aitbayeva Anastassiya P. Miroshnikova Reimar Seltmann Alla Dolgopolova Oxana N. Kuzmina Christophe Pascal Bakytzhan B. Amralinova Zinaida I. Chernenko Zhanar Z. Kapzhaparova

Rare-metal pegmatites of the Kalba–Narym belt (Eastern Kazakhstan) represent an important source of Li, Cs, Ta, Nb, Be, and associated critical metals. Despite extensive geological investigations, the relationships between granites, pegmatites, and late-stage alteration products within the Central Kalba ore district remain insufficiently constrained. This study integrates whole-rock geochemistry and muscovite trace-element data to evaluate regional fractionation trends and rare-metal enrichment within the granite–pegmatite system. The dataset comprises 29 whole-rock samples, including Phase I and Phase II granites, pegmatites, greisens, and hornfels, together with 11 muscovite separates from the Akhmetkino, Yubileynoye, Bakennoye, and Asubulak ore fields. Geochemical evolution was assessed using granite-normalized multi-element patterns and the Cs–Rb, K/Rb–Cs, Li–Rb, Li–Cs, Rb/Sr–Cs, and Ta–Cs relationships. Muscovite compositions were additionally compared with published datasets from the Totoral (Argentina) and Gatumba (Rwanda) pegmatite districts. The results reveal systematic enrichment in Li, Rb, Cs, Nb, and Ta accompanied by depletion in Sr and Ba from granites to the most evolved pegmatites. The strongest geochemical relationship is recorded by the Rb/Sr–Cs system (R2 = 0.805), whereas Ta and Cs show only weak correlation (R2 = 0.062). Muscovite compositions display decreasing K/Rb and K/Cs ratios and increasing Rb and Cs concentrations from Akhmetkino through Yubileynoye and Bakennoye to Asubulak, defining a regional fractionation sequence consistent with whole-rock geochemistry. The most evolved muscovites overlap compositional fields characteristic of highly fractionated LCT pegmatites. The geochemical patterns identified in both whole-rock and muscovite datasets indicate progressive melt evolution across the Central Kalba district. Late-stage alteration and volatile-rich mineral assemblages record additional fluid-related processes, although their quantitative contribution to rare-metal redistribution remains uncertain. The results identify Cs, Rb/Sr, K/Rb, and K/Cs as useful indicators of relative pegmatite evolution and provide new constraints on the development of rare-metal granite–pegmatite systems in Eastern Kazakhstan.

Geosciences doi: 10.3390/geosciences16080314

Authors: Yicheng Mou Wei Guo Zhengshuo Miao Yonghe Zhai Jingru Zhao Yongbo Wei Yangwen Pei

Fault networks play a critical role in controlling hydrocarbon flow within petroliferous basins; however, quantitative characterization of fault network systems and their specific influence on hydrocarbon preservation in tight sedimentary rocks remain insufficient. This study investigates the Luzhou shale gas production area in the Sichuan Basin, which has been modified by multi-stage tectonic superimposition, employing topological theory to quantitatively evaluate the structural architecture and connectivity of reservoir fault networks, and to elucidate their control on shale gas preservation. Our results reveal significant heterogeneity in the development and distribution of fault network systems within the study area. Faults are more developed in anticlinal belts, which experienced concentrated compressional stress, and the median connectivity of fault networks in shale reservoirs within these belts (CB = 1.34) is substantially higher than that in synclinal belts (CB = 0.95). The higher geometric connectivity observed in anticlinal belts may increase the continuity of potential migration pathways, whereas the generally lower connectivity of many synclinal areas may be more favorable for shale gas preservation. Estimated ultimate recovery data from shale gas wells in different structural zones show a spatial association broadly consistent with the fault-network connectivity pattern, although well performance may also be influenced by other geological and engineering factors. This study provides a quantitative analytical framework for characterizing fault-network connectivity in complex structural zones and offers insights into the potential role of fault-network connectivity in shale gas preservation and exploration.

Geosciences doi: 10.3390/geosciences16080313

Authors: Nazyf Salikhov Galina Pak Serik Nurakynov Dauren Kurmanov Alexander Shepetov Vladimir Ryabov Valery Zhukov

A study was performed on the electromagnetic response of the geological medium during the propagation of Rayleigh waves from the 2025 Kamchatka earthquakes (M8.8–7.4) at an epicentral distance of approximately 6000 km. The identities of the coseismic telluric current variations and the propagating Rayleigh wave have been revealed, with their power spectra exhibiting a pronounced quasi-line structure with dominant peaks at 0.04 Hz, 0.054 Hz, and 0.064 Hz. The high correlation of the telluric current response with the Rayleigh wave (r = 0.906, M8.8 and r = 0.83, M7.8) allowed the seismoelectric effect of the second kind to be considered the dominant mechanism for disturbance generation. Electromagnetic signals recorded by the IMS-008 induction sensor showed a lower correlation (r = 0.682), which may be attributed to the shaking of the induction sensor during the passage of the Rayleigh wave, though this does not preclude the presence of a true coseismic signal. Coseismic effects were recorded during the M7.8 and M8.8 earthquakes, but were absent during the M7.4 events. For the first time for the Northern Tien Shan region (at teleseismic distances of approximately 6000 km), key regularities in the generation of the seismoelectric effect during Rayleigh wave propagation have been identified. It is shown that the telluric current response is characterized by a threshold sensitivity to the event magnitude, with the magnitude of induced current variations strictly consistent with the intensity of the seismic wave’s dynamic impact. Utilizing telluric currents as a physical reference for the precise determination of Rayleigh wave arrival times allowed for the refinement of the Rayleigh wave group velocity (3.078–3.093 km/s), reducing calculation uncertainty to 0.5%.

Geosciences doi: 10.3390/geosciences16080312

Authors: Camilla Palmiotto Francesca Ape Malek Belgacem Lucia Bongiorni Luca Cocchi Alessia Conti Marco Cuffaro Giacomo Dalla Valle Amelia De Lazzari Eleonora Ficini Andrea Fiorentino Andrea Gallerani Fabiano Gamberi Donatella Domenica Insinga Maria Filomena Loreto Alessandra Mercorella Filippo Muccini Simone Muzzioli Yago Nestola Simone Orefice Alessandra Pensa Angelica Pesce Lorenzo Petracchini Francesco Riminucci Stefania Romano Marzia Rovere Fabio Savelli Anna Tozzi Marina Vingiani Valentina Ferrante

Despite its geodynamic significance, the northern Tyrrhenian Back-Arc Basin, characterized by a complex tectono-magmatic evolution, remains poorly investigated. We present the first geophysical characterization of the Flavia Seamount, a previously uninvestigated edifice in the northern Tyrrhenian Sea, integrating new multibeam, seismic, and magnetic data. The new high-resolution bathymetric data reveal a flat, nearly circular summit and strongly asymmetric flanks. Reduced-to-the-pole magnetic anomalies exhibit a north–south polarity pattern, with positive values in the northern sector and negative values in the southern sector. Seismic data, integrated with Sparker profiles collected in 1985, reveal a flat-topped acoustic basement overlain by a ~100 m thick stratified sequence and affected by inactive east-dipping extensional faults, indicating tectonic control on the evolution of the seamount. Widespread landslide scarps and associated mass-transport deposits document recurrent gravitational instability along the flanks and within surrounding basins. Pockmark morphometry suggests distinct formation processes, with summit pockmarks controlled by fluid seepage and gravitational processes, and basin pockmarks mainly related to fluid escape from mass-transport deposits. Magnetic forward modelling constrained by seismic data provides new insights into the distribution of magnetic susceptibility bodies and the crustal architecture beneath the seamount. Results suggest that the present-day morphology of the Flavia Seamount reflects the combined effects of tectonic, sedimentary, and gravitational processes.

Geosciences doi: 10.3390/geosciences16080311

Authors: Bouchra Cherradi Aude Duval-Arnould Abdallah Ait Salem Mohammed Farssi Asmae Benarchid Nadia Mhammdi

The Middle-Upper Jurassic carbonate succession of the onshore Essaouira Basin forms a hydrocarbon play comparable to Atlantic passive-margin systems. In the Toukimt field, gas and condensate have been produced from fractured Argovian dolomites, but reservoir prediction remains difficult because facies variability, diagenetic overprint, and fracture development generate heterogeneities. This study characterizes the sedimentological framework of the Callovian–Argovian (Middle Oxfordian) succession, establishes a sequence-stratigraphic framework, and evaluates the role of halokinesis in controlling accommodation and sediment distribution. The analysis integrates core-based sedimentology, well correlations, high-resolution sequence stratigraphy, and 2D-3D seismic interpretation. Four facies associations have been defined in the ramp system ranging from grain-rich biodetrital shoals to micritic outer-ramp facies. The succession is organized into four depositional sequences (DS1–DS4) showing a shallowing-upward trend with alternating retrogradational flooding and progradational colonization parasequences. Reservoir-prone intervals occur within highstand shoal facies, where depositional texture provides a favorable framework, while fracturing and dissolution enhance petrophysical properties. Seismic data reveal a gravity-driven rollover structure linked to west-dipping listric faulting and salt withdrawal within a long-lived halokinetic system active since the Early Jurassic. Basin-ward growth of the Tidsi diapir generated asymmetric subsidence, indicating that inherited structures, halokinesis, gravity sliding, and diagenesis jointly controlled accommodation, reservoir geometry and quality.

Geosciences doi: 10.3390/geosciences16080310

Authors: Bismark Ade Omid Ghorbanzadeh Thomas Blaschke

Artisanal and small-scale mining (ASM) is expanding across West Africa, driving deforestation, water contamination, and land degradation that require scalable monitoring approaches. Deep learning (DL) models applied to Sentinel imagery have shown acceptable performance for ASM mapping within individual countries, but their ability to transfer across national boundaries remains poorly understood. This study evaluates four DL segmentation models for ASM mapping in Ghana and Côte d’Ivoire, two major gold-producing countries with contrasting mining landscapes. The models were trained under three geographic scenarios of Ghana only, Côte d’Ivoire only, and both countries combined, using the SmallMinesDS benchmark dataset for Ghana and a newly compiled dataset for Côte d’Ivoire, both combining Sentinel-1 SAR and Sentinel-2 optical imagery. Models performed best when trained and tested on the same country, with U-Net++ (EfficientNet-B3) reaching IoU = 0.748 (F1 = 0.856) on Ghana. On the harder Côte d’Ivoire domain, models trained on Ghana alone transferred poorly (IoU = 0.488, F1 = 0.656), but training on both countries together gave the best result (IoU = 0.568, F1 = 0.724). Overall, the geography of the training data, rather than the model architecture or the use of SAR data, was the main factor driving performance, though some differences may also reflect the datasets being collected at different times.

Geosciences doi: 10.3390/geosciences16080309

Authors: Mingfang Lin Liang Zhang Yang Liu Jian Kong

Accurate short-term rainfall forecasting is essential for disaster mitigation. Although numerical weather prediction models are widely used, their application to short lead times is constrained by computational demands. Data-driven approaches provide an efficient alternative. To better exploit atmospheric water vapor information, this study develops a dual-branch long short-term memory (LSTM) model that integrates Global Navigation Satellite System (GNSS)-derived precipitable water vapor (PWV) with surface meteorological parameters for rainfall forecasting. The model processes historical rainfall and meteorological variables through separate branches. Historical rainfall characterizes precipitation persistence, while PWV, PWV variation (ΔPWV), PWV rate of change (ΔtPWV), and air temperature describe atmospheric moisture evolution and thermodynamic conditions before rainfall. The model was evaluated using hourly observations from 18 GNSS-collocated meteorological stations in Taiwan collected during 2018–2019 and compared with a rainfall history-based LSTM baseline model. Results show that the proposed model achieved accuracies of 89–91% and recalls of 88–90% for 1–3 h forecasts. Its advantages became more evident for longer lead times, with Recall and Threat Score increasing by 6–11% and 4–8%, respectively, for 2–3 h forecasts. These findings demonstrate that integrating GNSS-derived PWV with surface meteorological parameters can improve short-term rainfall forecasting.

Geosciences doi: 10.3390/geosciences16080307

Authors: Jiao Ye Fujie Dai Peng Tang

Geohazards in rock mass are essentially results of fracturing evolution. Regarding deeper exploration, to better contribute to evaluating and predicting instability, Particle Flow Code (PFC) has gained increasing popularity because of its logical resemblance in simulating rock composition and cracking processes. However, micro-parameter calibrations in PFC mainly focus on both the peak strength and macroscopic cracks in many previous, as well as current, studies, resulting in the existence of two widely used yet distinct strategies in stiffness calibration. The first is to ensure the consistency of the elastic modulus, and the second is to ensure the deformation consistency at peak-stress states. Do these two stiffness calibrations have a strength equivalence? To explore it, several rock mechanical tests—with and without confining pressures and a pre-existing flaw—were numerically conducted using PFC for two materials produced by these two distinct stiffness-calibration strategies. The results demonstrate that the two stiffness calibrations can yield equivalent strength parameters, including tensile strength, cohesion, and internal friction angle. This strength equivalence could be attributed to the evolutionary process of micro-crack initiation, accumulation, nucleation, and global failure (coalescence). Fracture mechanics analysis demonstrates that crack initiation is independent of the elastic modulus and marginally influenced by Poisson’s ratio, leading to a negligible impact of stiffness-calibration distinction on crack-initiation stress. Subsequent micro-crack accumulation follows a nearly identical non-linear increasing trend, with a high consistency of spatial distributions in stress concentration, displacement gradient, and strain localization. As a result, the near-identical structural logic in micro-crack nucleation results in failure-pattern consensus and governs the macro-scale strength equivalence of these two distinct stiffness-calibration strategies. These findings could help us to better comprehend those previous, as well as current, research results based on the two stiffness-calibration strategies.

Geosciences doi: 10.3390/geosciences16080308

Authors: Ye Duan Yongquan Chen Chengxin Liu Yan Cheng Fengguang Xu Hao Zhang Bing Zhang Peng Zhou Jiayu Jiang

Despite recent Cambrian subsalt gas discoveries in the Keping fault-uplift, northwestern Tarim Basin, organic abundance, type, maturity, and depositional setting of Lower Cambrian source rocks remain poorly documented. We evaluated the Yuertusi and Lower Xiaoerbulake Formations using total organic carbon (TOC) analysis, Rock-Eval pyrolysis, kerogen microscopy, solid bitumen reflectance, X-ray diffraction, and ICP-MS trace-element analysis of samples from 11 wells and 6 outcrops. The Yuertusi Formation is organic-rich in northern Keping (TOC = 0.13–28.20%) but thins and deteriorates southward. The Lower Xiaoerbulake Formation (TOC = 0.10–9.68%; 70–160 m thick) is a widespread, moderate-to-good source rock, challenging the view that the Yuertusi Formation is the only Cambrian source rock. Sapropelinite-dominated kerogen (>80%) indicates Type I–II organic matter; equivalent vitrinite reflectance (2.28–3.50%) confirms overmature, gas-prone rocks. The Yuertusi Formation reflects upwelling-fed high productivity and anoxic–euxinic waters; the Lower Xiaoerbulake Formation, moderately high productivity and dysoxic waters. The subsalt gas is oil-cracked gas from marine sapropelic source rocks of either formation. Chloroform bitumen “A” estimates give in-place gas resources of 1121.4 × 109 m3; the static share for southern Keping (20.1 × 109 m3) understates its dynamic potential. A lower-generation/upper-reservoir, fault-controlled, near-source model favors Trap 1-1 for future drilling.

Geosciences doi: 10.3390/geosciences16080306

Authors: Jianwei Chen Xin Wang Xuanlong Shan Xiaohan Li Yujie Zou Jian Yi

The basement lithology in the northern South China Sea remains poorly constrained because of the lack of drilling data, which creates major challenges for predicting bedrock buried-hill reservoirs. This study is based on 2D and 3D seismic data, together with gravity and magnetic data, and is constrained by previous studies on the regional tectonic framework and lithologic distribution of the northern South China Sea. We investigated the basement lithologic composition of the XS area, established an integrated gravity–magnetic–seismic interpretation framework for basement lithology, and discussed the possible geological controls on basement lithologic distribution. The results show the following: (1) The basement in the study area is mainly composed of granite intrusive bodies, metamorphic rocks, and volcanic rocks. Granite bodies are characterized by irregular to intrusive seismic geometries, strong double-peak reflections at the upper boundary, and weak-amplitude, medium- to low-frequency internal reflections, reflecting their intrusive characteristics. Metamorphic rocks show diverse external seismic geometries, single-peak or weak reflections at the upper boundary, and medium- to strong-amplitude parallel internal reflections that intersect the upper boundary at high angles. Their gravity and magnetic responses show considerable overlap with those of granitic rocks. Volcanic rocks commonly show mound-shaped or lenticular seismic geometries and medium- to strong-amplitude, moderately continuous internal reflections. Intermediate–mafic volcanic rocks are associated with relatively stronger gravity and magnetic anomaly responses, whereas felsic volcanic rocks generally exhibit weak to moderate gravity and magnetic responses. These characteristics provide an integrated seismic–gravity–magnetic constraint framework for basement lithology interpretation in the South China Sea. (2) Integrated gravity–magnetic–seismic interpretation indicates that, near the present top of the pre-Cenozoic basement in the XS area, granite intrusive bodies are the dominant lithology. Metamorphic rocks mainly occur as discontinuous basement remnants in local structural lows or erosional windows, whereas volcanic rocks are mainly distributed near fault intersections or occur as bead-like bodies along fault zones. (3) The distribution of granite intrusive bodies and metamorphic basement is interpreted to be related to Indosinian–Yanshanian magmatic activity, tectonic deformation, and subsequent denudation. Faults formed during Early Yanshanian compression were later reactivated during the Himalayan period and may have acted as magma conduits, promoting the development of volcanic edifices along fault zones.

Geosciences doi: 10.3390/geosciences16080305

Authors: Iarly Vanderlei da Silveira Gilberto Gomes

Reservoir-triggered seismicity (RTS) is commonly associated with stress perturbations induced by reservoir loading and pore-pressure diffusion within fractured rock masses. Shortly after the initial impoundment of the Irapé Hydropower Plant (Minas Gerais, Brazil), a sequence of induced earthquakes was recorded, providing an opportunity to investigate the compatibility between reservoir loading and the observed seismic response. This study presents a first-order hydromechanical assessment integrating finite element modelling, analytical elasticity solutions, and pore-pressure diffusion theory to evaluate the spatial distribution of stress perturbations and the characteristic diffusion times associated with reservoir impoundment. A two-dimensional elastic model was developed to simulate stress redistribution induced by the maximum reservoir load, while a parametric diffusion analysis was performed for representative hydraulic diffusivities and hypocentral depth scenarios between 1 and 6 km. Numerical results showed excellent agreement with the analytical elasticity solution (RMSE = 14.36 kPa, MAE = 11.08 kPa, mean relative error = 1.38%, and R2 = 0.999), supporting the reliability of the numerical model. The simulations indicate that vertical stress perturbations decrease from approximately 1.8–2.0 MPa immediately beneath the reservoir to about 0.01–0.1 MPa at kilometer-scale depths, where the recorded seismicity is presumed to occur. The diffusion analysis indicates that pore-pressure propagation to these depths generally requires substantially longer times than the interval between reservoir filling and the onset of seismic activity. Nevertheless, owing to uncertainties in hydraulic diffusivity, fracture connectivity, and hypocentral depth estimates, the diffusion results are interpreted as a first-order sensitivity analysis rather than a site-specific prediction. Overall, the results support the temporal compatibility and physical plausibility of rapid elastic stress redistribution as a potential triggering mechanism, while recognizing that the available geological and seismological data are insufficient to establish a direct causal relationship or demonstrate fault reactivation.

Geosciences doi: 10.3390/geosciences16080304

Authors: Mark R. Frank Marlena J. Rock

Lead and zinc mineralization have been documented in low-temperature Mississippi Valley type (MVT), Volcanogenic Massive Sulfide (VMS), and high-temperature porphyry and skarn ore deposits. These deposits are characterized by the precipitation of galena (PbS) and sphalerite (ZnS) from a saline hydrothermal fluid. The direct relationship between metal concentration and the total chloride of the fluid has been documented previously; however, the role of acidity has not been studied extensively. Experiments were conducted in René 41 cold-seal pressure vessels at temperatures of 200, 300, and 500 °C and a pressure of 100 MPa to provide better constraints on the formation of galena and sphalerite in hydrothermal systems spanning a range of fluid acidities (pH). The concentrations of Pb and Zn in the synthetic hydrothermal fluids were determined at galena and sphalerite saturation as a function of HCl and at a total chloride of 15 wt.% NaCleq.. Zn concentrations ranged from 1.7 (±0.3) × 102 µg/g at 200 °C and an HCl concentration of 2.28 × 103 µg/g to 2.55 (±0.5) × 103 µg/g at 500 °C and an HCl concentration of 3.40 × 104 µg/g. Pb concentrations were 1.8 (±0.4) µg/g at 200 °C and a HCl of 2.28 × 103 µg/g and increased to 7.93 (±1.5) × 103 µg/g at 500 °C and a HCl concentration of 3.40 × 104 µg/g. Zn/Pb mass ratios in the fluids at sphalerite and galena saturation decreased with increasing temperature. The experimental data demonstrate that the concentration of Pb and Zn in the fluid increase with both temperature and HCl concentration and, consequently, decrease with increasing pH. These results demonstrate that acidic fluids can transport substantially greater concentrations of Pb and Zn than neutral or basic fluids. Experimentally determined slopes of Pb and Zn concentrations as a function of HCl in the fluid provide empirical measurements of the apparent dependence of metal solubility on HCl at a constant total salinity. These results are consistent with Pb and Zn being transported predominantly as chloride-complexes under acidic, although the experiments do not directly determine aqueous metal speciation. Consequently, the experimentally determined HCl dependencies should be interpreted as empirical measures of apparent metal solubility rather than direct measurements of speciation or ligand coordination. The observed dependence of dissolved metal concentrations on HCl likely reflects the combined effects of chloride complexation, increasing HCl association with increasing temperature, non-ideal solution behavior, and changes in the distribution of dissolved chloride- and possibly sulfur-based complexes. Therefore, the neutralization of an acidic Pb- and Zn-bearing, chloride-rich hydrothermal fluid could produce substantial galena and sphalerite mineralization if sufficient reduced sulfur is available. In hydrothermal fluids depleted in reduced sulfur, H2S must be supplied through sulfate reduction or by mixing with an H2S-rich fluid to promote galena and sphalerite precipitation.

Geosciences doi: 10.3390/geosciences16080303

Authors: Xiaoke Huang Lichun Chen Liyan Ma Shuisheng You Yongfeng Cai An Li Liang Wang Hongda Wang Yongshun Jia Tianzi Zhi Xuhui Yu Wei Song

The Nujiang Fault Zone is located in the Three Parallel Rivers region on the southeastern margin of the Qinghai–Tibet Plateau, serving as a discordogenic fault that must be traversed by the Sichuan–Tibet transportation corridor project. Because of the scarcity of direct geological evidence, the late Quaternary activity of the Nujiang Fault Zone remains highly controversial. Focusing on the late Quaternary activity and active intensity of this fault, we conducted detailed field investigations along the Zuogong segment of the Nujiang Fault Zone based on high-resolution remote sensing images. Two trenches were excavated within a linear trough near Ranmi Village. Fourteen 14C samples were collected for AMS dating, and two fault gouge samples were obtained for microstructural analysis, aiming to reconstruct the paleoseismic sequence and estimate the corresponding earthquake magnitude. Clear fault planes were exposed in the trenches, which distinctly offset the middle-late Holocene strata. Three paleoseismic events were recorded by trench exposures: Event E1 prior to 5824 ± 61 cal BP (approximately 7031 ± 688 cal BP), Event E2 at 4560 ± 321 cal BP, and Event E3 at 1464 ± 142 cal BP. Analogous to the northern-central segment of the Longmenshan Fault Zone, where the Ms 8.0 2008 Wenchuan earthquake occurred, and its southern segment was associated with the Ms 7.0 2013 Lushan earthquake, microstructural observations of the fault gouge from the Zuogong segment also revealed typical brittle deformation characteristics. In terms of trenching-offset features, as well as the composition and microscopic properties of clay minerals in the fault gouge, the Zuogong segment exhibited geological signatures that were intermediate between the southern and northern-central segments of the Longmenshan Fault Zone, with greater similarity to the southern segment. Accordingly, the maximum potential earthquake magnitude of this segment was estimated to be Ms 7.0–7.5. The paleoseismic sequence of the Zuogong segment indicated an earthquake recurrence interval of approximately 2500–3000 years, with approximately 1500 elapsed years since the most recent seismic event. Although the full recurrence cycle has not yet been approached, implying low probability of great earthquakes with magnitudes of Ms 7.0–7.5 in the near future, the occurrence of non-characteristic seismic events cannot be ruled out. This study reveals direct evidence for Holocene activity along the Zuogong segment of the Nujiang Fault Zone, providing a critical scientific basis for quantitative seismic hazard assessment and major engineering planning and construction in the research area.

Geosciences doi: 10.3390/geosciences16080302

Authors: Xiaoxiao Ma Changrong Li Maowen Li Menhui Qian Tingting Cao Huimin Liu Zheng Li Yuxin Hao Miao Wang Enze Wang

Understanding how liquid hydrocarbons flow through nanoporous shale matrices is essential for predicting shale oil productivity and evaluating unconventional resources. Despite substantial advances in geological and geochemical characterization, the physical and chemical mechanisms governing oil mobility in tight shale media remain incompletely constrained. This knowledge gap has become particularly evident through an anomalous phenomenon: the prolific production of low-volatile black oil from low- to medium-maturity, extremely tight shale reservoirs, where such viscous oils were previously expected to exhibit limited mobility. This unexpected behavior challenges existing physical models of oil flow. In this Perspective, we revisit the key controls on oil mobility by integrating available geological, geochemical, and reservoir evidence, including the influence of lithofacies on pore systems, the effects of thermal maturity and organic matter on fluid properties, the mechanisms of overpressure generation, and the interactions between hydrocarbons and shale matrices. We particularly emphasize the physical–chemical interaction processes between hydrocarbons and shale matrices, which have been largely overlooked in previous models. Based on these analyses, we propose a conceptual cross-scale migration–accumulation framework for shale oil and discuss its implications using representative shale systems from North America and China. The available evidence indicates that oil mobility is jointly controlled by mineral composition, pore structure, pressure coefficients, hydrocarbon physical–chemical properties, and hydrocarbon–matrix coupling. Thermal maturity emerges as a key parameter because it modulates several of these controls and therefore affects effective oil flow. Despite regional differences, broadly comparable controls may operate across different shale systems. Laminated carbonate-rich shales deposited under saline conditions exhibit high oil mobility even at low maturity, whereas clay-rich freshwater lacustrine shales require higher maturity to achieve comparable flow. The proposed framework links pore-scale processes with reservoir- and basin-scale accumulation and may provide a conceptual basis for evaluating movable oil resource potential in different shale systems.

Geosciences doi: 10.3390/geosciences16080301

Authors: Ziying Li Mingming Tian Menghua Li Junxian Wang Jun Ning Jianfang Cai Linfei Qiu

The Hailijin uranium (U) deposit is one of the super-large U-deposits recently discovered in the Qianjiadian ore field, southwestern Songliao Basin. The ore bodies are mainly hosted in the lower member sandstones of the Upper Cretaceous Yaojia Formation and occur as multilayered tabular bodies. The nature and source of the ore-forming fluids remain unclear, limiting the understanding of the genetic type of the deposit. This study integrated drill-core observation, mineralogy, whole-rock geochemistry, in situ pyrite trace elements and sulfur isotopes, fluid-inclusion, and Raman spectroscopy to constrain ore-forming fluids. The host sandstones experienced hematitization, limonitization, carbonate cementation, clay alteration, sulfidation and bleaching. Pitchblende and coffinite occur as submicron grains in dissolution pores of quartz and feldspar, on clay-mineral surfaces and within mobile organic matter (OM), commonly associated with pyrite and sphalerite. The ores and gray mineralized sandstones are enriched in U, Mo, Re, Co, Ni, Zn and Pb, and syn-ore pyrite shows positive correlations between U and As, Mo, Cu, Zn, Se and Sb. Mineralization-related fluid-inclusion assemblages occur mainly in syn-ore dolomite/ankerite cements and in secondary trails along microfractures in detrital quartz; they yield homogenization temperatures of 130–190 °C and salinities of 3–8 wt.% NaCl eq., higher than the normal burial temperature of the basin (80–90 °C), especially meteoric fluid. Raman and gas-chromatographic analyses indicate carbonaceous matter, CH4, CO2, H2 and minor O2. Pyrite δ34S values of −49.24‰ to −23.1‰ indicate isotopically light reduced sulfur ultimately related to microbial sulfate reduction and/or thermal decomposition of sulfur-bearing OM, whereas thermochemical sulfate reduction was unlikely to be dominant. Therefore, the ore-forming fluid is interpreted as a low-temperature, low-salinity organic-rich fluid, most likely derived from U-enriched source rocks at depth, and the uranium mineralization is closely associated with the exudation of such deep-derived organic fluids.

Geosciences doi: 10.3390/geosciences16080300

Authors: Ieyasu Tokumoto Yuji Ito Hideki Miyamoto

Water-content changes in the upper few centimeters control the evaporation response, but this layer is difficult to measure at millimeter-scale spacing. We evaluated a printed-circuit-board-based multi-TDR probe (MTP) in a homogeneous sand column. The probe has eight three-wire measurement sections at depths of 0.28–2.52 cm. Electric-field simulation showed that the response of each section was localized around the embedded conductors, so the measured permittivity had to be treated as a probe-specific response. Calibration against gravimetrically determined water content confirmed that the εMTP–θ relationship differed from the standard Topp equation and required section-specific calibration. The calibrated MTP estimates agreed with the gravimetric reference values, with R2 = 0.996 and root mean square error (RMSE) = 0.0075 m3 m−3. During evaporation, MTP-derived profiles in the upper 0–30 mm were compared with HYDRUS-1D simulations constrained by pressure-head, mass-loss, and water-retention data. The MTP–HYDRUS comparison gave a pooled RMSE of 0.0376 m3 m−3 and a weighted mean absolute error (MAE) of 0.0282 m3 m−3, with the largest differences in the upper 0–20 mm. The results indicate that the MTP can provide independent millimeter-scale water-content profiles for checking near-surface water redistribution and for identifying depths where simulated surface-layer θ profiles depart from direct observations.

Geosciences doi: 10.3390/geosciences16080299

Authors: Kaitian Li Hao Qiu Hongjie Li Kai Lu Yuguang Lian Ruo Jia Wen Li Yue Wang

The Mao open-pit coal mine waste dump in Hequ, Shanxi, is a loose, anthropogenic mass accumulated over the original topography. Following a recent sliding and significant settlement event, this dump became the subject of intense stability concerns. Due to the high moisture sensitivity of its interlayered soil and coal gangue structure, rainfall infiltration can reduce internal effective stress, triggering slope instability. Although conventional geological surveys have mapped surface fractures, implementing precise, targeted drainage control requires characterizing the internal geometric structure and preferred seepage directions. To address this, this study integrates electrical resistivity tomography (ERT), surface nuclear magnetic resonance (SNMR), and spontaneous potential (SP) methods. Multiple ERT profiles (270–600 m long) were deployed across several benches at varying elevations, supplemented by fixed-point SNMR sounding over typical low-resistivity anomalies and dense SP grid scanning. The integrated results successfully delineate the internal architecture and seepage characteristics of the dump. Specifically, ERT imaging resolves the primary geoelectrical interface (tentatively inferred as the potential sliding surface) separating the overlying loose mass from the stable underlying strata while mapping the spatial extent of the inferred water accumulation zone (IWAZ). SNMR sounding quantitatively reveals a two-layer water-bearing structure at the specific sounding site, with a deep primary water-bearing zone at 45–80 m depth. Furthermore, SP inversions illuminate the seepage process, demonstrating that meteoric water deflects along the geoelectrical interface to converge laterally toward the central axis at approximately 42°, before transitioning into a high-angle vertical deep infiltration zone (61.7°) within the axial region. These findings suggest a potential engineering direction for remediating surficial fractures and designing subsurface drainage along this 1040 m bench axis, which would mitigate future landslide risks by reducing internal pore water pressure.

Geosciences doi: 10.3390/geosciences16080298

Authors: Igor M. Villa

The in vacuo release of Ar and other noble gases is well understood for single minerals. However, natural samples, even those seemingly pure under the optical microscope, mostly consist of mm-to-µm scale intergrowths of different minerals. Typically, relict phases and retrogression products are contained in minerals that are studied in sufficient detail. Only exceptionally can the number of different mineral generations be as low as two; single-generation gems (diamonds, rubies, emeralds) are not routinely used in geochronology. In polygenetic mixtures, the systematics of temperature-dependent release of artificial Ar isotopes used as compositional indicators (38Ar and 37Ar) can be linked to the 40Ar/39Ar ratio and disambiguate the ages of individual mineral generations.

Geosciences doi: 10.3390/geosciences16080297

Authors: Ba Manh Le Ting Yang Thi-Giang Ha Van-Duong Nguyen Thanh Hai Nguyen Van Vung Vi Thuy Linh Nguyen Van Duan Bui Minh Tuan Vu The Truyen Pham Anh Duong Nguyen

Petit-spot volcanism is a type of intraplate volcanism that commonly occurs near the outer rise in subducting plates. Although deformation of the incoming plate is considered important for its development, the deeper mantle processes contributing to this volcanism remain poorly understood. Here, we use more than 1500 broadband seismograms containing long-period SS precursors to investigate the mantle transition zone (MTZ) beneath the Sunda–Java subduction system. Beneath the northern Sunda–Java region, the 660 km discontinuity (d660) reaches ~690 km depth, resulting in an MTZ thicker than 270 km, consistent with the thermal influence of the subducted Indo-Australian slab. The associated weakening of S660S amplitudes may reflect hydration or other factors affecting the lower MTZ. South of the trench, the MTZ beneath most of the Christmas Island Seamount Province is relatively uniform, with a thickness of ~251 km. Beneath Christmas Island, however, the 410 km discontinuity (d410) is depressed to ~420–425 km, whereas d660 remains near 670–675 km, producing a localized thinner MTZ of ~245–250 km. This structure is compatible with localized slab-related mantle processes and may reflect thermal or compositional heterogeneity near the top of the MTZ. Although our observations do not directly resolve volatile transport or melt generation, they provide new constraints on the deep-mantle environment associated with rejuvenated petit-spot volcanism at Christmas Island.

Geosciences doi: 10.3390/geosciences16080296

Authors: Yanbin Zhou Guangchao Wen Hongbo Xie Yajie Feng Xiao Zhou

To address the separated organization of structural and attribute information in three-dimensional geological modeling for coal mine production, this study presents a three-dimensional geological structure–property coupled modeling method implemented through an integrated voxel-based workflow. A regular voxel model is used as a unified spatial carrier to organize stratigraphic structures, coal seams, boundaries, reserve parameters, and gas content attributes within the same spatial framework. Structural information is first identified under surface and boundary constraints, and attribute values are then assigned within structurally constrained voxel domains. Using production data from the Hemei No. 3 Mine, the method was applied at both mine and working-face scales to evaluate its implementation, engineering consistency, sensitivity, and uncertainty. The results show that the proposed method can jointly represent the coal seam geometry and gas content distribution and can support spatial query and reserve updating. At the mine scale, the voxel-based reserve estimate for the No. 2-1 coal seam differed from the traditional geological block estimate by 1.67%. At the working-face scale, as an engineering consistency check, the relative difference between the voxel-based estimate and the engineering reference estimate decreased from 31% to 8.4% after additional borehole constraints were incorporated. Additional validation and sensitivity tests yielded quantified errors for gas content and working-face coal-seam geometry estimation. The results further show that reserve estimates are affected by voxel resolution and apparent density assumptions, whereas the spatial distribution of gas content estimates is affected by the tested IDW parameters. Therefore, the proposed method provides a practical application-oriented modeling and updating method under the data conditions of the case study, while broader transferability requires further independent validation and more systematic uncertainty analysis.

Geosciences doi: 10.3390/geosciences16070295

Authors: Álvaro-Francisco Morote Daniel López-Rodríguez Bàrbara Micó-Vicent Jorge Jordán-Núñez Jorge Olcina Antonio Belda

The floods triggered by the 29 October 2024 cut-off low in Valencia (Spain) expose a persistent challenge in disaster risk reduction: extensive meteorological and territorial data do not automatically become timely, trusted or actionable public guidance. This conceptual synthesis uses the Valencia event as a diagnostic case and reconstructs selected evidence on rainfall, hydrological escalation and alert timing to develop a data-driven framework spanning observation, modelling, impact assessment, communication, decision-making and post-event learning. Here, “data-driven” denotes an end-to-end governance and translation process, not the development of a new forecasting model. The framework integrates four dimensions: data governance, user-centred visualization, uncertainty communication and school-based education. It also introduces territorial translation as the link between impact forecasts and place-specific infrastructures, routines, vulnerabilities and responsibilities. Its novelty lies in connecting the Early Warnings for All pillars and impact-based, people-centred warning approaches with an explicit educational and territorial learning loop. Its practical contribution is a responsibility matrix, a minimum governance package and an implementation roadmap with indicators for latency, reach, comprehension and protective action. The framework is intended for adaptation, rather than statistical generalization, across Mediterranean and other fast-onset flood contexts. Improved forecasts remain necessary but insufficient: loss reduction requires interoperable records, accessible impact-based messages and inclusive educational programmes that convert scientific information into situated collective competence.

Geosciences doi: 10.3390/geosciences16070294

Authors: Shuai Yuan Xianfeng Wang Qinghai Sun Zhiguo Wang Guantao Tai Guangyao Zhang Shuai Liu

Densely distributed small holes significantly affect the mechanical behavior and fracture characteristics of rock masses. In this study, the two-dimensional particle flow code was employed to establish a series of numerical models of dolomitic limestone, with the number of small circular holes increasing according to the sequence (2n − 1)2 (n = 1–6). Comparative models with equivalent area and variable spacing were additionally designed to explore their regulatory effects. The strength, crack evolution, and contact force chain distribution of each model were systematically analyzed. The results reveal that the number of small holes exhibits an approximately linear negative correlation with the rock strength. The number of holes dominates the crack initiation location and propagation path. The crack initiation stress gradually decreases with increasing hole number, while the ratio of crack initiation stress to peak stress exhibits a V-shaped trend. As the hole number increases, the distribution of compressive force chains shifts from the sides of holes to the vertical strips between holes, and tensile force chains become significantly enhanced in the areas above and below the holes. Hole spacing and equivalent area exert only local modulating effects; the number and spatial arrangement of holes remain the dominant controls on strength deterioration and fracture evolution. These findings offer a theoretical foundation for stability assessment in rock masses characterized by densely distributed hole defects.

Geosciences doi: 10.3390/geosciences16070293

Authors: Shu Li Guangqing Hu Tao Zhang Chun Lan Hetao Tang Lei Peng Shasha Hu Qiwei Deng Xiaojun Zhu

The surface subsidence caused by coal mining is a geological environmental disaster that restricts the sustainable development of mining areas. Traditional monitoring methods have limitations in long-term and high-precision observation. Therefore, this paper proposes a synergistic monitoring framework for mining subsidence under thick loose layers by integrating Interferometric Synthetic Aperture Radar (InSAR) technology and Unmanned Aerial Vehicle (UAV) photogrammetry. The research results show: (1) UAV photogrammetry can accurately obtain the large gradient deformation at the center of the subsidence basin, while InSAR has better accuracy at the basin edge. The proposed fusion method is significantly superior to a single method. (2) The parameters obtained by the probability integral method based on the fused data are in good agreement with the parameters obtained by leveling measurement data, and the relative error of the parameters is less than 4%. (3) The thick and loose-layered mining areas have the characteristics of larger subsidence, steeper gradient at the center, slow convergence at the edge, and wide influence range. This study provides a new approach for precise subsidence monitoring, and the revealed subsidence characteristics provide a scientific basis for disaster assessment and mining optimization in similar areas.

Geosciences doi: 10.3390/geosciences16070292

Authors: Tongyan Lü Sheng Wang Zhonghai Wu Kungang Wu Minqiang Liang

In southern Tibet, tectonic extension has created north–south rift systems that host hydrothermal zones with episodic silica sinter and travertine deposition. Earlier researchers usually attributed these deposits to hydrothermal activity driven by regional tectonics. However, the timing of deposition and its possible climatic controls remain poorly constrained. In this study, we dated six samples from the Targejia geothermal field and the Xiakangjian hot spring area using electron spin resonance (ESR), and evaluated ESR signal stability, dose response, and irradiation effects to assess age reliability. The new ages range from 209 to 49 kyr. When combined with 108 published ages, they indicate repeated sinter and travertine formation over the past 720 kyr. The dated deposits are concentrated in several intervals, especially during the last 100 kyr, and some age clusters occur near warm and humid stages. These patterns suggest that tectonics controlled where hydrothermal systems developed, whereas climate-related changes in recharge, meltwater supply, permafrost thaw, and water–rock interaction may have affected when deposition was more active. Because the compiled ages come from different methods and have uneven uncertainties, this climate link remains provisional and needs testing with additional samples dated by consistent protocols.

Geosciences doi: 10.3390/geosciences16070291

Authors: Xinwen Xu Shenghui Wang Wen Liu Guohui Liu

The varying sensibilities of diverse proxies to Indian Summer Monsoon (ISM) variables lead to inconsistencies across individual studies. To attain a comprehensive understanding of the ISM driving mechanisms, it is essential to compile multi-proxy paleorecords from diverse monsoon-influenced areas. However, terrestrial ISM records spanning the last 200 ka remain sparse. Here, we performed a magnetic analysis of the PT2 core lacustrine sediments from the Heqing Basin, covering the past 184 ka, to reconstruct ISM variations from millennial to orbital timescales. According to the rock magnetic results, samples displaying strong magnetization are dominated by substantial amounts of magnetite and maghemite, accompanied by a broad grain-size distribution. Conversely, samples with weak magnetization show only limited quantities of fine-grained magnetite. The decrease in magnetic mineral concentration is attributed to the reduction in both coarse and fine-grained particles. Magnetic mineral dissolution intensity (MMDI) which combines magnetic susceptibility and frequency-dependent magnetic susceptibility, is highly sensitive to ISM changes. Consequently, we derived an ISM index from the MMDI and geochemical indicators of the PT2 core lacustrine sediments. This index exhibits pronounced “glacial–interglacial variations”, aligning with other regional ISM indicators from southwestern China and a variety of ISM-related proxies from a broader range of ISM-influenced areas. This suggests that ISM intensity is more sensitive to glacial boundary conditions in high-latitude ice sheets.

Geosciences doi: 10.3390/geosciences16070290

Authors: Changpei Zou Zhenggong Pu Linyang Zhuo Huaying Wu Hongwei Liao Tengfang Li Pengyu Liu Kun Ren Qibo Huang

The Shangri-La area lies within the Yunnan-Tibet geothermal belt, characterized by intense tectonic activity and abundant geothermal resource potential. However, existing studies have largely focused on individual hot springs, and a regional scale understanding of geothermal geology and fluid circulation mechanisms remains lacking. This study systematically elucidates the geological setting, hydrogeological characteristics, circulation mechanisms, and resource potential of the geothermal systems by integrating hydrogeological surveys with hydro chemical and isotopic analyses. The results indicate that the Zhongxiao Fault Zone and its associated secondary structures are the primary controllers of geothermal water distribution, serving as both thermal conduits and hydrogeological boundaries. The primary heat source is attributed to the natural geothermal gradient, supplemented by additional contributions from magmatic activity. The geothermal waters are classified as Na-HCO3 or Ca-HCO3 types and are notably rich in fluoride. The mean values of δD and δ18O for geothermal water were −127.86‰ and −15.53‰, respectively, exhibiting isotopic depletion compared with non-thermal water. The geothermal water samples plot near both the Global and Local Meteoric Water Lines while exhibiting a distinct mean 18O shift of +1.24‰, indicating that the systems are recharged by atmospheric precipitation and have subsequently undergone intense water–rock interaction. Analysis using the Na-K-Mg triangle diagram reveals that most geothermal water samples are immature waters. Thus, the quartz geothermometer provides more reliable estimates of reservoir temperatures. Calculations yield reservoir temperatures ranging from 70 °C to 123 °C, characterizing the system as a medium-to-low temperature resource. With an annual exploitable energy of 5.9 × 1014 J and high fluoride content, these resources can offer substantial potential for clean energy and balneotherapy.

Geosciences doi: 10.3390/geosciences16070289

Authors: Abdelmadjid Benrabah Salvador Senent Domínguez Luis Jorda-Bordehore

Volcanic caves, commonly referred to as lava tubes, are typically shallow subsurface cavities formed by the cooling of a generally basaltic lava flow under a roof or crust that cools faster and acts as a thermal insulator. These cavities can serve as tourist attractions, in which case their stability must be analyzed and ensured. Empirical rock mass classification systems, in this case we have applied the Q-index have been employed to evaluate the stability of underground excavations: mines and tunnels, including natural caves. We have identified that these approaches have limitations, particularly incorporating key geometric parameters such as roof thickness and cave length. In this study we have analyzed applicability of the Scaled Span Method (SSM) to volcanics caves. This method was originally developed for the stability assessment of crown pillar stability in shallow mines. We have developed a dataset of lava tubes (caves) located in the Canary Islands (Spain), the Galápagos Islands (Ecuador), and Jordan. In this research we have conducted geomechanical characterization using the Q-system, and also the Scaled Span to evaluate stability based on cave geometry and rock mass properties. The results indicate that, in general, the SSM yields more conservative stability estimates compared to the Q-system, particularly for shallow caves with limited roof thickness. Nevertheless, discrepancies between the two approaches are observed in several cases, highlighting the limitations of directly transferring empirical methods developed for mining excavations to natural cave systems. These differences underscore the need for careful interpretation and, where appropriate, complementary stability analyses. The Scaled Span Method is useful for preliminary assessment of volcanic cave stability, especially in scenarios where potential interaction with the ground surface is expected: buildings or roads on top. However, its application requires adaptation and critical evaluation due to the fundamental differences between engineered mining excavations and natural subsurface cavities.

Geosciences doi: 10.3390/geosciences16070288

Authors: Mohamed Hamouyahia Nasrrddine Youbi Brian Cousens Abderrahmane Soulaimani Hassane Oubaassine Hicheme Houane Youssef Atif El Hassane Chellai Moulay Ahmed Boumehdi Lhou Maacha Mohamed Zouhair Lahcen Rakhiss

This study investigates the provenance, weathering history, and tectono-sedimentary evolution of lower Ediacaran siliciclastic rocks of the Imiter Formation (Saghro Group, Imiter Sub-inlier, Anti-Atlas, Morocco) deposited along the northern margin of Gondwana. An integrated approach combining petrography, whole-rock major and trace element geochemistry, rare earth elements (REEs), Sm–Nd isotopes, and organic geochemistry (TOC and δ13Corg) was used to constrain sediment sources and depositional conditions. Geochemical proxies, including Th/Sc, La/Sc, and Zr/Sc ratios, together with REE distribution patterns, indicate that the sediments were mainly derived from felsic-to-intermediate rocks of the upper continental crust, with only minor sediment recycling. The negative εNd(t) values (−8.5 to −6.2) and Paleoproterozoic Nd model ages (1.6–2.1 Ga) further suggest the erosion of evolved crustal sources related to the West African Craton. Weathering indices (CIA, CIW, PIA) suggest weak-to-moderate chemical weathering under predominantly arid conditions. Redox-sensitive proxies (V–Ni, V/Cr, V/(V + Ni)) and low TOC content (0.1–0.3 wt.%) indicate deposition under mainly oxic-to-dysoxic conditions, with only transient reducing episodes. Tectonic discrimination diagrams, supported by regional magmatism, point to sedimentation within an extensional basin evolving from active-margin to continental rift conditions during the late Pan-African orogeny. The Imiter Formation records a system dominated by crustal recycling, syn-rift tectonics, and dynamic redox conditions in a shallow marine environment.

Geosciences doi: 10.3390/geosciences16070287

Authors: Ryosuke Saito Airi Takano Yusuke Sawaki Mathieu Moussavou Amboise Edou-Minko

Direct molecular evidence for ancient photosynthetic pigment inputs in early Proterozoic sedimentary rocks remains scarce, partly because of long-standing concerns about contamination in Precambrian biomarker studies. Here, we report maleimide and phthalimide compounds released by chromic-acid oxidation of bitumen-free kerogen from ca. 2.1 Ga black shales of the Franceville Basin, Gabon. The detected assemblage includes 2-methylmaleimide, 2,3-dimethylmaleimide, 2-methyl-3-ethylmaleimide, and phthalimide, whereas higher-alkyl maleimides commonly associated with bacteriochlorophyll c-, d-, and e-derived inputs were not detected. Paired analyses of kerogen isolated from exterior and interior rock portions show near-unity exterior/interior ratios and broadly similar relative compositions, supporting a kerogen-bound origin rather than substantial surficial contamination. In the context of organic-rich marine shales containing evidence for microbial ecosystems, the detected compounds are most plausibly interpreted as reflecting photosynthetic pigment inputs, especially (bacterio)chlorophyll-related tetrapyrrole precursors. The absence of higher-alkyl maleimides may reflect either limited original inputs from anoxygenic phototrophs or the preferential degradation of higher-alkyl maleimides during thermal alteration. Overall, these results show that kerogen-bound maleimide-type compounds provide a promising approach for tracing ancient tetrapyrrole and photosynthetic pigment inputs in Precambrian sedimentary rocks.

Geosciences doi: 10.3390/geosciences16070286

Authors: José Cléber do Nascimento Sales Sâmilly de Carvalho Saraiva Ana Clara Paiva Guimarães Gabriela França Azevedo Claver Giovanni da Silveira Pinheiro Alfran Sampaio Moura

This study evaluates the shear strength and geomechanical behavior of the soil–concrete interface in carbonate sands from the coast of Ceará, with particular relevance to offshore wind turbine foundations. Three sands with different calcium carbonate (CaCO3) contents, namely, 10.6%, 22.0% and 30.0%, were tested under applied normal stresses of 50, 100 and 200 kPa. Conventional direct shear tests were carried out to determine soil–soil shear behavior, whereas controlled-interface tests were performed using cementitious specimens with smooth and rough surfaces. The soil–soil tests indicated effective internal friction angles (φ′) between 35° and 38°, with no cohesion. No direct correlation was observed between shear strength and CaCO3 content. Instead, the results indicate that particle size distribution, particularly the proportion of finer fractions, exerted the main control on mechanical behavior. Within the three materials tested, no monotonic trend between CaCO3 content and shear strength was identified, a finding that should be confirmed with a larger sample set. At the soil–concrete interface, shear stress mobilization depended on surface roughness, with the rough surface mobilizing higher shear stresses than the smooth surface. The ratio between the interface friction angle and the soil effective internal friction angle (δ/φ′) ranged from 0.963 to 0.994 for rough surfaces and from 0.859 to 0.951 for smooth surfaces. These findings show the need for site-specific characterization of carbonate sands and for explicit consideration of interface conditions in offshore foundation design, thereby reducing unnecessary structural oversizing.

Geosciences doi: 10.3390/geosciences16070285

Authors: Roberta Esposito Lucia Nardone Roberto Manzo Guido Gaudiosi Massimo Orazi

This study investigates the seismic ambient noise within the Campi Flegrei caldera (Naples, Italy) to improve the detection capability and reliability of the earthquake monitoring system managed by the INGV, Osservatorio Vesuviano. It focuses on the spectral characteristics and spatial variability of the ambient noise field, aiming to identify the dominant frequency bands that control signal detectability and to provide information for optimizing the monitoring network. Due to the dense urban environment surrounding the caldera, seismic recordings are often contaminated by anthropogenic noise, which can mask low-magnitude volcanic or seismic signals. Power spectral density (PSD) analysis was applied to evaluate background noise levels at several broadband stations from permanent and temporary seismic networks over the period January 2022 to January 2023. The resulting PSD estimates were compared with the global Peterson noise models to assess station performance. Results show marked variability among stations, related to local human activity, proximity to infrastructure, and different installation settings (buried vs. surface). The study emphasizes the importance of noise monitoring to ensure high-quality seismic data, support optimal station siting, and refine monitoring strategies in densely populated volcanic regions such as Campi Flegrei, where the reliable detection of low-amplitude seismic and volcanic signals is essential.

Geosciences doi: 10.3390/geosciences16070284

Authors: Marzhan Rakhymberdina Roman Shults Baitak Apshikur Yerkebulan Bekishev Yevgeniy Grokhotov Azamat Kapasov Damir Mukyshev

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Geosciences doi: 10.3390/geosciences16070283

Authors: Koji Wakita

This study examines all 48 members of the Japanese Geoparks Network to explore how human societies live with the Active Earth in one of the world’s most tectonically active regions. Rather than treating geoparks as separate sites, the study analyzes them collectively in terms of geoheritage, geohazards, hydrological environments, and community-based activities. The study is organized around four interconnected perspectives: (1) local geoheritage and Deep Time, (2) geohazards linking Human Time and Deep Time, (3) human life within Earth-system circulation, and (4) people and local communities connected through geopark participation. The results show that Japanese geoparks collectively preserve records of plate subduction, magmatism, accretion, crustal deformation, uplift, erosion, and hydrological processes that have shaped the Japanese active margin over hundreds of millions of years. These same processes continue to influence contemporary society through earthquakes, volcanic eruptions, water resources, ecosystems, agriculture, fisheries, and regional livelihoods. This nationwide analysis suggests that Japanese geoparks can be understood not only as sites for geoheritage conservation or tourism, but also as places where people recognize and sustain relationships among Earth-system processes, everyday life, and local communities.

Geosciences doi: 10.3390/geosciences16070282

Authors: Long Yang Yueping Yin Sainan Zhu

At approximately 05:51 on 22 January 2024, a catastrophic red-bed rock avalanche with a volume of 16 × 104 m3 occurred in Zhenxiong County, Yunnan Province, southwestern China (105°00′47″ E, 27°28′54″ N). The detached rock mass buried 18 houses, killed 44 people, and caused economic losses of 145 million CNY (23.1 million USD). Field investigations, unmanned aerial vehicle (UAV) imagery, interferometric synthetic aperture radar (InSAR) analysis, and two-dimensional discrete-element modelling using PFC2D were conducted to examine the deformation characteristics, failure causes, and kinematics of the rock avalanche. The results show that internal factors, including high-relief terrain resulting from tectonic activity, fractured rock masses caused by joint cutting and weathering, and a soft–hard interbedded stratigraphic structure associated with argillaceous interlayers, were primarily responsible for the failure. Frost heaving may have been an important triggering factor for the Liangshuicun rock avalanche. Continued attention should be paid to slopes around the rock-avalanche site because ground deformation is still ongoing and may lead to future catastrophic events. The numerical simulation reveals that the kinematic process of the rock avalanche from initiation to final deposition lasted approximately 30 s. About 20 s after failure, the rock debris reached the village, burying houses and killing residents. The maximum velocity and displacement of the rock debris were 45 m/s and 335 m, respectively. These findings provide insight into the instability mechanisms and risk assessment of red-bed rock avalanches in the study area.

Geosciences doi: 10.3390/geosciences16070281

Authors: Hao Wang Yang Liu Luguang Luo Lizhen Wang Yulong Lu

This study systematically elucidates the mechanisms of hydraulic performance of geosynthetic clay liners (GCLs) by using tailings leachates from two representative mines, Xikuangshan and Shizhuyuan, in Hunan Province. A series of physical parameter tests, including fluid loss, free swell index, and liquid limit, together with microstructural characterization using X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM), were conducted to clarify the governing processes underlying the degradation of GCL performance in the presence of tailings leachates. The results demonstrate that the Xikuangshan tailings leachate markedly diminishes the hydraulic barrier performance of the bentonite component of the GCLs. This reduction primarily results from the exchange reactions between the high-valence cations in the leachate and the interlayer cations of bentonite. Such cation exchange compresses the diffuse double layer, reduces the swelling potential, and consequently manifests macroscopically as a pronounced increase in fluid loss and decreases in both the free swell index and the liquid limit. Microstructural observations further reveal that although the dominant mineralogical composition of the bentonite remains unchanged, its pore structure undergoes notable alteration: the hydraulic radius increases, the clay fabrics (crystallites) become looser and more dispersed, and the permeant pathways become more conductive. In addition, the hydraulic conductivity of GCLs permeated by different test solutions was estimated based on the measured fluid loss. The calculated values were slightly higher than the measured permeabilities, indicating that the proposed method can provide conservative estimates for rapid evaluation of GCL hydraulic performance.