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Geosciences, Volume 16, Issue 9 (September 2026) – 42 articles

Cover Story (view full-size image): Remote sensing methods are increasingly being used to create large geologic datasets of discontinuity orientations in rock masses, which presents new challenges in extracting useful data for analysis. Reducing hundreds of thousands of datapoints to representative dip and dip direction is important for applications ranging from rock slope stability and foundation design to mining and understanding groundwater flow and contaminant transport. A new proof-of-concept approach presents a novel approach that combines a two-step filtering process with unsupervised clustering to identify representative joint set orientations from point clouds while accounting for natural variability in large rock masses. View this paper
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16 pages, 5086 KB  
Article
Identification and Analysis of Fracture Zones in Tunnels Based on GPR Wave Characteristics
by Shixin Dai, Jialong Xiao, Bin Li and Hengshun Yin
Geosciences 2026, 16(9), 385; https://doi.org/10.3390/geosciences16090385 - 21 Sep 2026
Viewed by 233
Abstract
With the growing complexity of mountain tunnel construction and the increasing engineering demand for rapid detection, ground-penetrating radar (GPR) has become a core technique for engineering-scale fracture detection. Fracture zones are not only a major obstacle to tunneling through complex geological sections but [...] Read more.
With the growing complexity of mountain tunnel construction and the increasing engineering demand for rapid detection, ground-penetrating radar (GPR) has become a core technique for engineering-scale fracture detection. Fracture zones are not only a major obstacle to tunneling through complex geological sections but also a key trigger of tunnel hazards, posing a serious threat to construction safety. Consequently, the effective identification of fracture zones and the investigation of their development characteristics remain central challenges in advance geological prediction for mountain tunnels. Owing to the complex morphology of fracture zones, existing approaches—including simple model simulation, single-parameter identification, and integrated prediction methods—cannot adequately characterize core attributes such as connectivity and development degree. To address this challenge, this study constructed a fracture attribute model and established a multidimensional collaborative identification system covering fracture scale, connectivity, and density, integrating time-domain wave-frequency morphology with the two instantaneous attributes in the spatial domain, namely instantaneous frequency and instantaneous amplitude. A collaborative analysis scheme based on multiple GPR statistical attributes was adopted to perform a qualitative comparison of fracture development characteristics by tracking multidimensional parameter trends. The results reveal that fracture zones in different development states exhibit certain correlation trends between their internal structural features (e.g., connectivity and compactness) and the frequency-related physical attributes of electromagnetic waves (e.g., wave-frequency morphology and instantaneous frequency). Based on the simulation results, the analysis of waveform characteristics, spatial variations of the two instantaneous attributes, and multi-attribute evolution trends clarified the correlation trends between the wave-frequency response patterns and the fracture development degree. These findings provide scientific and theoretical guidance for geological prediction in tunnel engineering in Hunan, China, and lay a foundation for the GPR-based identification of fracture zones in tunnels. Full article
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22 pages, 12196 KB  
Article
Constraints of Tectono-Hydrothermal Alteration on Permian Volcanic Reservoir Formation as Recorded by Fluid Inclusions
by Hongjiao Li, Hao Hu, Yixue Xiong, Bing Tan, Yuhui Ge and Aihua Xi
Geosciences 2026, 16(9), 384; https://doi.org/10.3390/geosciences16090384 - 21 Sep 2026
Viewed by 204
Abstract
The origin of effective porosity in the Permian volcanic reservoirs of the Sichuan Basin remains poorly understood, particularly regarding the contribution of deep-sourced hydrothermal fluids. This study presents an integrated analysis of the Emeishan basalts, combining petrography, fluid-inclusion microthermometry, and laser Raman spectroscopy. [...] Read more.
The origin of effective porosity in the Permian volcanic reservoirs of the Sichuan Basin remains poorly understood, particularly regarding the contribution of deep-sourced hydrothermal fluids. This study presents an integrated analysis of the Emeishan basalts, combining petrography, fluid-inclusion microthermometry, and laser Raman spectroscopy. Three broad hydrothermal fluid characteristics were identified, ranging from low-temperature CH4-H2S-bearing to medium–high-temperature hydrocarbon-rich alkaline fluids. Their influence on porosity was tectonically modulated: fluids associated with the Indosinian and Yanshanian orogenies primarily degraded the pore system through clay infill and siliceous cementation. In contrast, the Himalayan orogeny may have driven a constructive shift. Sodic (Na-rich) fluids channeled along deep faults drove extensive local dissolution, creating secondary, micron-scale pore occurrence. Simultaneously, the temperatures recorded by this medium–high-temperature hydrothermal system fall within a range permissive for in situ hydrocarbon thermal alteration. This is tentatively consistent with models of vertical hydrocarbon migration and accumulation, but does not constitute direct evidence for in situ cracking or charging. Therefore, the Himalayan tectono-hydrothermal event is regarded as a possible contributor to the development of potential volcanic gas reservoirs. This work proposes a unified interpretive genetic model that couples late-stage alkaline-fluid dissolution with possible hydrocarbon alteration effects, offering a predictive framework for exploring volcanic reservoirs in similar geodynamic settings. Full article
(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)
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22 pages, 5519 KB  
Article
Early Miocene Adakitic Granite Porphyry in the East Kunlun Orogen: Implication on Melting of Thickened Ancient Lower Crust During Post-Collision
by Talifeng Biedilihan, Mingming Shi, Jianbang Zhao, Yuxiang Zhao, Yufei Su, Shuaitao Yan and Xiuwen Liu
Geosciences 2026, 16(9), 383; https://doi.org/10.3390/geosciences16090383 - 20 Sep 2026
Viewed by 210
Abstract
Cenozoic felsic magmatism along the northern Tibetan Plateau records the evolution of thickened continental crust, yet Miocene intrusions in the East Kunlun Orogen remain poorly constrained. Here we integrate field and petrographic observations with zircon U-Pb geochronology, zircon Lu-Hf isotopes, and whole-rock geochemistry [...] Read more.
Cenozoic felsic magmatism along the northern Tibetan Plateau records the evolution of thickened continental crust, yet Miocene intrusions in the East Kunlun Orogen remain poorly constrained. Here we integrate field and petrographic observations with zircon U-Pb geochronology, zircon Lu-Hf isotopes, and whole-rock geochemistry for the Ganquanhe biotite monzogranite porphyry. Sample TW6 contains two zircon 206Pb/238U age populations at 14.8 ± 0.2 Ma and 17.5 ± 0.2 Ma, whereas the coherent TW7 population yields the preferred crystallization age of 17.6 ± 0.2 Ma; these uncertainties include a conservative 1% external reproducibility term. The overlapping εHf(t) ranges of the two TW6 age groups support a common magma source and indicate that the younger dates most likely record Pb loss rather than a separate magmatic event. The high-K calc-alkaline, metaluminous to weakly peraluminous rocks have low Y and Yb, high Sr/Y and (La/Yb)N, fractionated rare earth element (REE) patterns, and weak Eu anomalies. Low MgO, Cr, and Ni contents, negative zircon εHf(t) values, and Mesoproterozoic TDM2 ages indicate derivation mainly from ancient, garnet ± amphibole-bearing lower crust. Whole-rock zircon saturation temperatures of 760–782 °C and Sr/Y- and (La/Yb)N-based crustal-thickness estimates of approximately 72–77 km indicate melting within a warm, strongly thickened crust. Major-element source discrimination further favors an amphibolitic lower-crustal source with possible subordinate graywacke–orthogneiss components. The intrusion therefore records Early Miocene lower-crustal melting within a collisional to post-collisional setting along the northern Tibetan Plateau. Full article
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28 pages, 21463 KB  
Article
Spatiotemporal Characteristics and Trends of Climate Extremes in and Around the Yunnan Reach of the Nujiang River Basin
by Yaxin Zhang, Wanting Sun, Yiyue Zhao, Ailing Lei, Tiezheng Li, Xi Xiang and Fei Zhao
Geosciences 2026, 16(9), 382; https://doi.org/10.3390/geosciences16090382 - 20 Sep 2026
Viewed by 228
Abstract
Daily observations from 14 stations and ERA5 reanalysis were used to examine temperature, precipitation, and wind extremes in and around the Yunnan reach of the Nujiang River Basin during 1991–2020. Twelve station indices, two reanalysis-derived wind indices, and circulation diagnostics describe their spatial, [...] Read more.
Daily observations from 14 stations and ERA5 reanalysis were used to examine temperature, precipitation, and wind extremes in and around the Yunnan reach of the Nujiang River Basin during 1991–2020. Twelve station indices, two reanalysis-derived wind indices, and circulation diagnostics describe their spatial, seasonal, and interannual variability. The regional annual maximum of daily maximum temperature (TXx) and annual minimum of daily minimum temperature (TNn) increased by 0.50 and 0.55 °C per decade, respectively. Warm-night and warm-day frequencies increased by 3.98 and 3.00 percentage points (pp) per decade, whereas cold-night and cold-day frequencies decreased by 2.67 and 2.87 pp per decade. Recorded wet-day precipitation had a fitted trend of −69.27 mm per decade (Newey–West 95% confidence interval: −110.03 to −28.51 mm per decade; p = 0.002), with considerable interannual variability (R2 = 0.135). Climatological wet-day precipitation ranged from 847.46 mm at Yunxian to 2016.39 mm at Longling over the study period. Using identical station thresholds and matched valid days, ERA5 warm-day, cold-night, and heavy-precipitation frequencies differed from observations by −5.89, +7.14, and +0.40 pp, respectively. ERA5 annual maximum hourly 10 m wind speed showed no significant regional trend (+0.01 m s−1 per decade; p = 0.791). Seasonal circulation and humidity fields provide context for the observed annual cycle of temperature and precipitation extremes. Overall, the station network shows a shift towards warmer temperature extremes and strong spatial contrasts in precipitation; ERA5 captures shared annual frequency variations while yielding different mean frequencies and event dates, supporting separate evaluation of temporal covariability and local event occurrence. Full article
(This article belongs to the Special Issue Climate Risks and Impacts)
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12 pages, 37506 KB  
Review
Review on the Permian–Triassic Boundary (PTB) in Abadeh (Iran), a Traveling Boundary
by Aymon Baud and Micha Horacek
Geosciences 2026, 16(9), 381; https://doi.org/10.3390/geosciences16090381 - 20 Sep 2026
Viewed by 278
Abstract
The Permian–Triassic transition along the South Cimmerian margin of the Neotethys in Abadeh (Iran) is built by four successive lithologies/events with apparently no gaps: (1) the stop of the skeletal carbonate factory of the Paratirolites limestone caused by the end-Permian mass extinction event [...] Read more.
The Permian–Triassic transition along the South Cimmerian margin of the Neotethys in Abadeh (Iran) is built by four successive lithologies/events with apparently no gaps: (1) the stop of the skeletal carbonate factory of the Paratirolites limestone caused by the end-Permian mass extinction event (EPME); (2) replacement of carbonate deposits by the up to 0.3 m thick boundary clay, defining the base of the Elikah Formation; (3) sudden emergence of a sponge-microbial carbonate factory with buildups of ca. 1.6 m, called the microbial unit; (4) a thick succession of platy lime mudstone. Despite continued research for over 50 years, there still exists significant debate concerning the exact base of the Triassic. This is partially due to different proxies used for the identification of the Permian–Triassic boundary (PTB). Since the boundary was defined by the first appearance (FA) of the conodont Hindeodus parvus at the Global Stratotype Section and Point (GSSP), there is continued discussion concerning its earliest occurrence in Abadeh. Ongoing research shows the boundary at different stratigraphic levels: at the EPME horizon below the microbial unit, at its base, within the middle part, or at the base of the platy limestone beds directly above the microbial unit. We review the existing data, explain which level we regard as real PTB and recommend steps to achieve an agreement in the scientific community on the position of the PTB in Abadeh. Full article
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27 pages, 30999 KB  
Article
Overlapping Damage Zones in a Bedrock Aquifer
by Stephanie L. Latour, Norman L. Jones, Stephen T. Nelson, John McBride, Kevin A. Rey and Benjamin C. Barton
Geosciences 2026, 16(9), 380; https://doi.org/10.3390/geosciences16090380 - 19 Sep 2026
Viewed by 243
Abstract
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, [...] Read more.
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. Full article
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18 pages, 8063 KB  
Article
Geochemical Behavior of Rare Earth Elements in Hydrothermal Groundwaters of Western Sicily (Italy)
by Marianna Cangemi, Ygor Oliveri, Salvatore Inguaggiato, Rocco Favara and Paolo Madonia
Geosciences 2026, 16(9), 379; https://doi.org/10.3390/geosciences16090379 - 19 Sep 2026
Viewed by 281
Abstract
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), [...] Read more.
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. Full article
(This article belongs to the Section Geochemistry)
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25 pages, 6143 KB  
Article
Full-Flowfield Inversion of Debris-Flow Dynamics: A Global–Local Optimization Framework for Model Parameter Estimation from Final Accumulation Fields
by Mauricio Secchi, Massimo Mangifesta and Nicola Sciarra
Geosciences 2026, 16(9), 378; https://doi.org/10.3390/geosciences16090378 - 17 Sep 2026
Viewed by 228
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Geophysical Inversion)
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34 pages, 11203 KB  
Review
Electrical Responses of Rock Masses: Conductive Network Evolution, Damage Characterization and Instability Precursors
by Mingyang Zhong, Peng Jia and Hongyuan Liu
Geosciences 2026, 16(9), 377; https://doi.org/10.3390/geosciences16090377 - 17 Sep 2026
Viewed by 380
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Section Geomechanics)
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23 pages, 45397 KB  
Article
Geomechanical Characteristics of Cretaceous Ultra-Deep Sandstone Reservoirs in the Southern Keshen Area, Kuqa Depression: Implications for Exploration and Development
by Ke Xu, Yixiong Hu, Hui Zhang, Wei Ju, Weike Ning, Penglin Zheng, Jiajun Zhang, Zhongwei Zhang, Qiuyu Chen and Yuanhang Qi
Geosciences 2026, 16(9), 376; https://doi.org/10.3390/geosciences16090376 - 16 Sep 2026
Viewed by 207
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Fault Characteristics, Fault Zone Architecture and Fluid Behavior)
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24 pages, 10338 KB  
Article
Porosity Prediction in Tight Reservoirs via Elastic Decoupling Factor-Constrained Prestack Density Inversion: A Case Study from the Bohai Bay Basin
by Cai Li, Tong Qin, Teng Liu, Dongjia Hou and Fei Ma
Geosciences 2026, 16(9), 375; https://doi.org/10.3390/geosciences16090375 - 16 Sep 2026
Viewed by 170
Abstract
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 [...] Read more.
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. Full article
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28 pages, 19444 KB  
Article
Numerical Simulation of Interlevel Pillar Response During Underground Gold Ore Mining: The Akbakay Deposit Case
by Serik Moldabayev, Alikhan Khairullayev, Olena Sdvyzhkova, Dmytro Babets, Samal Assylkhanova and Nurzhigit Sarybayev
Geosciences 2026, 16(9), 374; https://doi.org/10.3390/geosciences16090374 - 15 Sep 2026
Viewed by 250
Abstract
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 [...] Read more.
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. Full article
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7 pages, 1364 KB  
Commentary
Synonymy in Taxonomy: Where Is the Evidence?
by George H. Scott
Geosciences 2026, 16(9), 373; https://doi.org/10.3390/geosciences16090373 - 15 Sep 2026
Viewed by 240
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Section Biogeosciences)
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15 pages, 5908 KB  
Review
Excessive Southwest Greenland Ice Sheet Melting Between 4.4 and 3.2 ka BP Documented by Fjord Sediments: Implications for N-Atlantic Ocean Circulation and AMOC
by Antoon Kuijpers and Marit-Solveig Seidenkrantz
Geosciences 2026, 16(9), 372; https://doi.org/10.3390/geosciences16090372 - 15 Sep 2026
Viewed by 330
Abstract
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 [...] Read more.
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’. Full article
(This article belongs to the Section Climate and Environment)
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53 pages, 4640 KB  
Article
Stochastic Foundations of Atmospheric Thermodynamics: Deriving the Laws from Maximum Entropy and Implications for Earth’s Climate
by Demetris Koutsoyiannis
Geosciences 2026, 16(9), 371; https://doi.org/10.3390/geosciences16090371 - 14 Sep 2026
Viewed by 1527
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Section Climate and Environment)
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45 pages, 15210 KB  
Article
The First True Large Canis lupus? Canidae (Carnivora, Mammalia) from Caves of the Połom Mt (Sudetes, Silesia, SW Poland) and Their Significance in Biochronological Analyses in a Eurasian Context
by Aleksandra Kropczyk and Adrian Marciszak
Geosciences 2026, 16(9), 370; https://doi.org/10.3390/geosciences16090370 - 14 Sep 2026
Viewed by 794
Abstract
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 [...] Read more.
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. Full article
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33 pages, 34926 KB  
Article
Characteristics and Formation Mechanisms of Cambrian Platform-Margin High-Energy Shoal Reservoirs in the Yudu Area, Tarim Basin
by Yang Liu, Junhui Li, Ran Xiong, Bo Yan, Rui Deng, Yuangao Zhang, Xiandong Wang, Yong Zhong, Yanqing Cao and Shan Zhao
Geosciences 2026, 16(9), 369; https://doi.org/10.3390/geosciences16090369 - 13 Sep 2026
Viewed by 418
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Sedimentary Basins and Energy Resources)
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24 pages, 4000 KB  
Article
Inclusive Geotourism in Japanese Geoparks: Expanding Possibilities Together
by Koji Wakita and Tatsuru Nishio
Geosciences 2026, 16(9), 368; https://doi.org/10.3390/geosciences16090368 - 13 Sep 2026
Viewed by 287
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Section Geoheritage, Geoparks and Geotourism)
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21 pages, 4899 KB  
Article
A Dynamic Early Warning Model for Rainfall-Induced Landslides Coupling Slope Units and Rainfall Thresholds: A Case Study of Jinyang County, Southwest China
by Feng Zhang, Qili Xie, Yong Zhang, Jinyang Li, Jingsong Yi, Qing He, Lu Jiang, Ping Wang and Shilong Sun
Geosciences 2026, 16(9), 367; https://doi.org/10.3390/geosciences16090367 - 13 Sep 2026
Viewed by 319
Abstract
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 [...] Read more.
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. Full article
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18 pages, 2954 KB  
Article
Evolutionary Characteristics and Mesoscopic Mechanisms of the Effective Stress Coefficient in Rock Fractures Under Complex Stress Paths
by Yu Jiao, Mengmeng Tao, Yuan Wang, Di Feng, Zhikui Wang and Jie Ren
Geosciences 2026, 16(9), 366; https://doi.org/10.3390/geosciences16090366 - 13 Sep 2026
Viewed by 251
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Topic Advances in Groundwater Science and Engineering)
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31 pages, 11938 KB  
Article
Evaluation of the Correlation Between Surface Geophysical and Subsurface Hydraulic Parameters: A Case Study from Raya Valley, Northern Ethiopia
by Leul Fisseha Zemichael and Tesfamichael Gebreyohannes
Geosciences 2026, 16(9), 365; https://doi.org/10.3390/geosciences16090365 - 11 Sep 2026
Viewed by 292
Abstract
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 [...] Read more.
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. Full article
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19 pages, 12670 KB  
Article
Surface Geochemistry of Natural Hydrogen: Modelling of Soil Artefacts Versus Active Hydrogen Seeping
by Marie-Christine Cacas-Stentz and Alain Prinzhofer
Geosciences 2026, 16(9), 364; https://doi.org/10.3390/geosciences16090364 - 10 Sep 2026
Viewed by 348
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Natural Hydrogen: From Generation Mechanisms to Exploration Advances)
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20 pages, 24063 KB  
Article
Research on the Seismogenic Mechanism of the 2025 Mw = 6.9 Dingri Earthquake
by Wenqiang Wu and Jiaoyang Yu
Geosciences 2026, 16(9), 363; https://doi.org/10.3390/geosciences16090363 - 10 Sep 2026
Viewed by 387
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Section Natural Hazards)
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26 pages, 62840 KB  
Article
Technique Analysis of Filter-Clogging Particulate Matter in Eddy Covariance Systems in a Volcanic Environment
by Assunta Donato, Donatella Spadaro, Sonia La Felice, Dario Giuffrida, Rosina Celeste Ponterio, Catia Cannilla, Gianna Vivaldo, Ilaria Baneschi, Simone D’Incecco and Maddalena Pennisi
Geosciences 2026, 16(9), 362; https://doi.org/10.3390/geosciences16090362 - 9 Sep 2026
Viewed by 290
Abstract
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 [...] Read more.
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. Full article
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18 pages, 11866 KB  
Article
Geometric Controls on Cascading and Supershear Rupture Across a Wavy Strike-Slip Fault
by Jiankuan Xu and Yang Xu
Geosciences 2026, 16(9), 361; https://doi.org/10.3390/geosciences16090361 - 8 Sep 2026
Viewed by 334
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Section Geophysics)
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18 pages, 15526 KB  
Article
Landslide Hazard Assessment Based on a Spatial–Temporal–Magnitude Multiplicative Composite Index: A Case Study of Guiyang in China
by Junhua Luo, Ting Luo, Weiquan Zhao and Wei Li
Geosciences 2026, 16(9), 360; https://doi.org/10.3390/geosciences16090360 - 8 Sep 2026
Viewed by 284
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Resilience and Adaptation to Cascading Geohazards)
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30 pages, 1450 KB  
Article
A Two-Criterion Framework for Reaction-Set Reduction in Geochemical Simulation of CO2 Mineral Trapping in Basaltic Formations: Integrating Mineral Trapping Efficiency and pH Buffer Capacity
by Aiko Nishizaki, Shota Itoyama and Yuichi Sugai
Geosciences 2026, 16(9), 359; https://doi.org/10.3390/geosciences16090359 - 7 Sep 2026
Viewed by 390
Abstract
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 [...] Read more.
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. Full article
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20 pages, 14687 KB  
Article
Stress-Dependent Permeability of Artificially Fractured Siliceous Rocks from Southern Sakhalin
by 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 and Evgenii V. Kozhevnikov
Geosciences 2026, 16(9), 358; https://doi.org/10.3390/geosciences16090358 - 7 Sep 2026
Viewed by 302
Abstract
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 [...] Read more.
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. Full article
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25 pages, 14682 KB  
Article
High-Resolution Sequence Stratigraphic Framework and Sedimentary Evolution of the Chang 7 Member of the Yanchang Formation, Zhidan Area, Ordos Basin, China
by Yanna Wu, Jinning Zhang, Yongxu Mei, Wenjie Wang, Peiye Liu, Haodong Lin, Yiming Cui and Jiehao Su
Geosciences 2026, 16(9), 357; https://doi.org/10.3390/geosciences16090357 - 7 Sep 2026
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Abstract
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, [...] Read more.
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. Full article
(This article belongs to the Special Issue Sedimentary Basins and Energy Resources)
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Article
Machine Learning-Based GNSS Positioning Error Compensation for Static Receivers
by Viorel Carbune, Maria Gutu, Irina Cojuhari, Lilia Rotaru and Vladimir Melnic
Geosciences 2026, 16(9), 356; https://doi.org/10.3390/geosciences16090356 - 5 Sep 2026
Viewed by 314
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Earth Observation by GNSS and GIS Techniques, 2nd Edition)
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