Geosciences doi: 10.3390/geosciences16110456

Authors: Mohammad Tahir Muhammad Zafar Iqbal Raja Adnan Habib Muhammad Tahir Iqbal Muhammad Naveed Mushtaq Farhan Javed Talat Iqbal Aftab Alam Muhammad Ali Shah Kyriaki Kiskira Nikitas Gerolimos Michail Papoutsidakis Avraam Chatzopoulos Christos Drosos Georgios Priniotakis Ioannis Voyiatzis Georgios Prezerakos Dimitrios Nikolopoulos

The moderate-magnitude (Mw 4.5) 26 May 2026 Jalalpur Sharif earthquake in northern Pakistan caused localized severe damage, one fatality, and a maximum Modified Mercalli Intensity (MMI) of VII. Field observations documented liquefaction-related ground deformation, transient groundwater turbidity, differential settlement, tilted utility poles, and earthquake-induced landslides in Quaternary deposits. Moment tensor inversion indicates shallow (~3 km) oblique-thrust faulting, with NE–SW strike direction (strike 217°, dip 55°, rake 46°). Gravity modeling reveals a ~20 mGal residual anomaly aligned with the Pabbi Anticline, supporting structural complexity and the presence of shallow faulting, although the causative fault cannot be uniquely resolved. Regional seismicity is concentrated at 10–15 km depth, with a peak near 12 km, indicating depth-dependent deformation within the sedimentary cover and deeper regional thrust system. Coulomb stress modeling shows negligible static stress changes (~0.001 bar) at Jalalpur Sharif from the 2019 Mw 5.8 Mirpur and 2024 Mw 5.0 Kharian earthquakes, providing little support for direct static triggering. The localized damage likely resulted from the combined effects of shallow faulting, potentially liquefiable sediments and vulnerable buildings. These findings highlight the importance of incorporating shallow seismogenic structures and local ground conditions into seismic hazard assessments across the eastern Potwar foreland.

Geosciences doi: 10.3390/geosciences16110455

Authors: Željka Fiket Simona Spasovska Elena Šimić Igor Felja

Karstic deltas preserve complex sedimentary records in which changes in element concentrations may reflect depositional conditions rather than contamination. This study investigated sedimentological and geochemical variability in surface sediments, four shallow cores, and the approximately 5 m long NER7 core from the Neretva River Delta (Croatia) to reconstruct changes in the depositional environment and assess possible anthropogenic influence. Sediment pH, organic matter content, grain size distribution, and total concentrations of 26 elements were determined, and element associations were evaluated using Spearman rank correlations and Al normalisation. Recent sediments ranged from coarse-grained, organic-poor coastal deposits to finer-grained, organic-rich marsh sediments. Core NER7 contained two compositionally distinct units separated by a transition zone at approximately 245–300 cm. The deeper unit was alkaline, organic-poor, and enriched in Ca and Mg, whereas the upper unit contained more organic matter and higher concentrations of Al-associated elements. These coordinated changes indicate a transition from an estuarine or lagoonal environment to a marsh and delta-plain setting during delta infilling. Most trace element variability was controlled by changes in aluminosilicate, carbonate, and organic matter components. Localised Cu and Pb enrichment may indicate limited anthropogenic inputs, but the available data cannot quantify anthropogenic contributions independently of natural sediment variability.

Geosciences doi: 10.3390/geosciences16110454

Authors: Steven Puerta-Campo Oscar E. Coronado-Hernández Manuel Saba

The application of artificial intelligence (AI) to rainfall–runoff modelling in catchments has attracted increasing attention in recent years because of its ability to represent complex hydrological relationships with relatively low computational requirements. This study presents a surrogate modelling framework for estimating mean daily streamflow in gauged catchments using machine learning (ML) and deep learning (DL) approaches. The methodology was applied to the Mocoa River basin in Putumayo, Colombia. Several ML algorithms were trained, validated, and tested to assess their predictive performance. In addition, DL models were implemented and evaluated for comparison with the ML approaches. The results indicated that the DL models provided better predictive performance than the ML models considered in this study. In particular, the Gated Recurrent Unit (GRU) model achieved the lowest RMSE, with a value of 18.36 m3/s, whereas the best-performing ML model, the Interactions Linear Model, achieved an RMSE of 40.00 m3/s. The models were developed using daily rainfall records from two rain-gauge stations and mean daily streamflow records from one stream-gauging station. The proposed methodology provides a computationally efficient approach for streamflow estimation in catchments with available hydrometeorological records. The surrogate modelling framework may support applications in hydrological assessment, water-resource management, and flood-risk analysis by providing timely estimates of mean daily streamflow. It may also offer a practical modelling approach for environmental agencies, water-resource managers, and other stakeholders requiring streamflow information to support hydrological decision-making.

Geosciences doi: 10.3390/geosciences16110453

Authors: Germán Flor Jaime Bonachea Jesús Ángel Ortea Patricio Martínez-Cedrún

The embayed beaches of northern Spain’s cliffed, wave-dominated coast contain mixtures of siliciclastic sands, supplied mainly by rivers and coastal erosion, and carbonate bio-clastic sands derived from coastal organisms. The proportion of carbonate material, expressed as a percentage of CaCO3, is a reliable indicator of the provenance and transport patterns of sediments. This parameter frequently yields more precise information than grain-size analysis. It is well established that the carbonate content typically diminishes in the direction of sediment transport from the original source. At a regional scale, sediment transport along the Cantabrian coast and much of Galicia is predominantly west-to-east, driven by prevailing northwest and west-northwest wave conditions. While large rivers supply abundant siliciclastic sediments, estuaries, rias, mudflats, and marshes contribute nutrients that enhance marine productivity and carbonate production. In the coastal regions of Galicia, the phenomenon of coastal upwelling has been shown to increase biological productivity, thereby fostering the development of carbonate-rich sediments. The skeletal assemblage is classified as bimol-bivalve dominated. Consequently, elevated carbonate percentages are indicative of regions influenced by nutrient-rich upwelling and productive coastal ecosystems. Across approximately 750 km of the Galician and Cantabrian coastline, variations in bioclastic carbonate content help define coastal compartments, identify sediment sources, and infer longshore transport pathways. In the context of the continental shelf, the interplay of opposing currents generated by northern swells, in conjunction with the influence of the rias, exerts a pronounced regulatory effect on the dispersal of sand and the dynamics of the coastline.

Geosciences doi: 10.3390/geosciences16110452

Authors: Zhaojun Song Shufen Liu Siyuan Chen Ning Wang Xuan Ke Shuwen Guo

Conventional adaptive subtraction methods for multiple attenuation rely solely on predicted multiples, resulting in poor removal at near offsets. To address the issue, we develop an adaptive subtraction based on joint matching filtering (ASMF) algorithm. It is developed under the premise that the common midpoint (CMP) gathers consist of primaries, multiples and random noise. The algorithm assumes that accurate primaries can be obtained from the far-offset traces of the CMP gathers. Another assumption is that the near-offset and far-offset data in the gathers differ mainly in terms of fluids, amplitude variation, frequency attenuation, and signal-to-noise ratio (SNR). The method further assumes that corresponding primary events remain approximately aligned after normal moveout (NMO) correction and that angle-dependent reflectivity variations are limited and do not involve polarity reversals. After conventional separation, selected far-offset traces of the preliminary primary estimate are stacked to estimate a zero-phase wavelet for reflection coefficient inversion. The resulting reflection coefficient is convolved with trace-dependent wavelets to obtain the predicted primaries. Based on the predicted primaries and multiples, the matching filtering operators for both components are jointly calculated under the framework of morphological component analysis (MCA). Incorporating the predicted primaries into joint fitting can help improve the separation of primaries and multiples. Numerical experiments and field data tests demonstrate that, compared with the Radon transform and conventional adaptive subtraction, the proposed algorithm can effectively improve the accuracy of multiple attenuation.

Geosciences doi: 10.3390/geosciences16110451

Authors: Egor Illarionov Oleg Babakin Artem Mironchikov Vsevolod Avilkin

Conventional geostatistical methods of spatial interpolation (e.g., inverse distance weighting or kriging) are based on spatial distance and become inaccurate in regions far from sample wells or in the case of geological discontinuities. It looks more natural to estimate geological properties using similarity, not by distance, but by geological conditions, which, in turn, can be estimated using seismic surveys. In this research, we use machine learning to derive seismic attributes that describe the local geological environment and apply interpolation in the resulting attribute space to propagate geological properties from the sample wells to the whole reservoir model. In this representation, geologically similar regions become close in the attribute space even when they are separated in the initial spatial 3D domain. Using an open synthetic dataset, we demonstrate that this approach improves propagation of various geological properties compared to the conventional spatial method and remains effective even with a small number of sample wells. The main advantage of this approach is that, while preserving the simplicity and transparency of geostatistical methods, it enables the use of seismic data without preliminary interpretation to obtain geologically consistent and quick estimates of geological properties in the 3D domain far from sample wells.

Geosciences doi: 10.3390/geosciences16110450

Authors: Leqi Liu Hongxia Li Bo Liu Xi’ao Wang Zhou Jiang Boyang Wang Jianguo Yang Fei Xiao Lijuan Cheng Yuhui Feng

The Member I of the Qingshankou Formation (91.89~90.97 Ma) is the most significant lacustrine shale in the Songliao Basin, and preserves a continuous and complete record of terrestrial paleoenvironmental conditions and organic matter (OM) accumulation during the early Late Cretaceous. Although its abundant OM has traditionally been attributed to deep-lake anoxia, the accumulation mechanism in shallow to semi-deep lake settings remains unclear. To address this gap, samples from the JYY1 well in the Changling Sag were analyzed for TOC, iron species, and major/trace elements. The Al2O3/TiO2 ratios and PAAS-normalized REEs patterns indicate the provenance is predominantly felsic to intermediate rocks, broadly compatible with tonalite. Geochemical proxies (τNa, V/Cr, FeHR/FeT, Fepy/FeHR, B/Ga, Ti/Al, etc.) indicate a relatively humid climate, ferruginous to ferruginous-euxinic bottom waters, and brackish to saline conditions during the Member I deposition. In shallow to semi-deep lacustrine settings, redox conditions and detrital dilution were the principal controls on OM accumulation. The upper interval exhibits higher TOC because of improved OM preservation under ferruginous-euxinic bottom-water and weaker detrital dilution. In contrast, stronger detrital dilution and ferruginous bottom waters contributed to the lower TOC of the lower interval. These findings suggest that widespread pyrite occurrence and elevated Fepy/FeHR ratios may help identify organic-rich shale intervals and guide shale oil and gas exploration.

Geosciences doi: 10.3390/geosciences16110449

Authors: Eva Pescatore Mario Bentivenga Salvatore Ivo Giano

Geodiversity represents a cornerstone concept at the intersection of geological, environmental, and biological sciences. As an abiotic equivalent of biodiversity, it encompasses the natural variety of geological, geomorphological, hydrological, and pedological features, as well as their assemblies, structures, systems, and functional processes. Its ecological significance is clear: geodiversity serves as the fundamental physical scaffold underpinning ecosystems, driving the complex, non-linear relationships that sustain biotic communities and regulate ecosystem services. In recent years, a growing number of studies have focused on refining the conceptualization of geodiversity and developing quantitative and qualitative frameworks for thematic mapping across multiple spatial scales—from local landforms to regional landscapes. However, translating these cartographic and spatial assessments into actionable conservation measures remains a critical challenge. Rigorous characterization of geodiversity is an indispensable prerequisite for geoconservation, as it provides the baseline evidence needed to identify abiotic vulnerability, establish protection priorities, and guide sustainable territorial planning. This paper presents a theoretical framework for classifying geodiversity, specifically structured in relation to target geoconservation actions. By categorizing abiotic elements through operational steps, this study provides a systematic decision-support tool that aligns diverse geodiversity components and vulnerability levels with specifically tailored conservation, restoration, and management actions.

Geosciences doi: 10.3390/geosciences16110448

Authors: Qin Zhu Jinfeng Li Xidong Zhou Wenchong Shan

Rainfall infiltration commonly triggers shallow landslides by raising pore-water pressure and reducing shear strength. This mechanism, however, presupposes that the soil structure remains stable. In colluvial slopes composed of gravelly soils, rainfall infiltration may induce the migration of fine particles, a phenomenon known as internal erosion that alters the soil structure and consequently affects slope stability. To investigate internal erosion in colluvial gravelly soil under different rainfall intensities and its effects on water migration and soil structural characteristics, a series of laboratory soil column tests were conducted using a self-designed rainfall infiltration apparatus. The wetting front migration, soil moisture evolution, and fine-particle outflow under five rainfall intensities (30, 60, 90, 120, and 150 mm/h), together with the changes in grain-size distribution and pore structure before and after the tests, were systematically analyzed. The results indicate that rainfall intensity exerted a markedly layer-dependent influence on the infiltration process of colluvial gravelly soil: the steady-state moisture content increased most markedly in the upper layer and moderately in the lower layer but remained almost unchanged in the middle layer. Under the present test conditions, a rainfall intensity threshold of 30–60 mm/h was identified for the onset of fine-particle mobilization. Below this threshold, no particle washout occurred. Once it was exceeded, the effluent fine-particle concentration exhibited an initial peak followed by a later-stage decline, and the cumulative eroded mass increased with rainfall intensity. The vertical distribution of particle loss was closely aligned with the moisture content response across layers. The image-estimated porosity change rate at the front face of the soil column increased with rainfall intensity. It was negative under low-intensity rainfall, with values of −5.07% and −4.63% at 30 and 60 mm/h. At higher intensities, it turned positive, reaching 5.4% at 90 mm/h and 19.88% and 33.96% at 120 and 150 mm/h. Under rainfall intensities of 120 and 150 mm/h, coarsening zones and seepage pathways became visible on the column surface. This study demonstrates that rainfall-driven internal erosion can substantially alter the hydraulic and structural properties of colluvial gravelly soils under controlled laboratory conditions. The findings improve our understanding of rainfall-induced internal erosion in colluvial gravelly soils and provide an experimental reference for evaluating its implications for slope stability.

Geosciences doi: 10.3390/geosciences16110447

Authors: Muhammad Aufaristama Achmad Fakhrus Shomim Dini Nurfiani Muhammad Faizal Rafli Mohammad Hasib Yogi Adi Prasetya Emilia Khusnul Wafi Ratika Benita Nareswari Aditya Pratama Estu Kriswati

Digital elevation model (DEM) choice can alter stochastic lava-routing results where crater rims, depressions, and narrow channels are represented differently. We compared four source-location tests at Mount Slamet: an interpreted southwest-trending channel, the central crater, the western rim, and the southern crater. The elevation products were a 0.530 m unmanned aerial vehicle (UAV)-derived surface elevation model, Indonesia’s 8.29 m national DEM (DEMNAS), and 30 m Shuttle Radar Topography Mission (SRTM) data. Each DEM–source combination was run four times with 1500 trajectories per replicate. The analysis distinguishes native-grid summaries from common 30 m support and reports visitation-weighted radial reach, trajectory runout, directional concentration, convergence, and termination. The channel test retains a concentrated southwestward distribution on all three products. The other UAV tests remain close to their source cells and have weak directional concentration, so their bearings do not define a clear preferred direction. Regional products generally produce broader and longer distributions, but the response varies among source locations and is not monotonic with cell size. Frequent routing-exception stops and contrasting scales of fixed routing corrections identify unresolved numerical effects. The comparison demonstrates sensitivity to DEM choice under fixed inputs; it does not establish UAV superiority, eruption probability, or validated inundation limits.

Geosciences doi: 10.3390/geosciences16110446

Authors: Tengjiao Zhang Hong Liu Yifu Zeng Hao Song Chengjiang Zhang Shiwei Song Xiangfei Zhang

The magma sources and tectonic significance of Late Triassic Cu-bearing intrusions in the northern Yidun Arc remain less well constrained than those of the southern segment. This study integrates geological observations, zircon U–Pb geochronology and whole-rock geochemistry to investigate the Changdagou granodiorite porphyry. LA-ICP-MS analyses of 23 magmatic zircons yield a weighted mean 206Pb/238U age of 215.4 ± 0.5 Ma (MSWD = 0.53), constraining Late Triassic crystallization of the Cu-bearing intrusion. The analyzed rocks contain 67.40–68.16 wt.% SiO2 and exhibit high-K calc-alkaline and weakly peraluminous compositions, with A/CNK values of 1.03–1.14. Their rare earth element patterns show light rare earth element enrichment relative to heavy rare earth elements and negative Eu anomalies (δEu = 0.48–0.68). Primitive mantle-normalized patterns display enrichment in Rb, Th and K and depletion in Nb, Ta, P and Ti. Low Ga/Al ratios and decreasing P2O5 contents with increasing SiO2 support an I-type granitoid affinity. Relatively low Mg# values (33–36), together with low Nd/Th and Nb/Ta ratios, suggest a substantial crustal contribution to magma generation. Trace-element discrimination results and regional geological relationships support an association with the tectonomagmatic system established by westward subduction of the Ganzi–Litang Ocean. These results complement previous zircon-based investigations by providing whole-rock constraints on the petrogenesis and tectonic affinity of the Changdagou intrusion within the Late Triassic magmatic framework of the northern Yidun Arc.

Geosciences doi: 10.3390/geosciences16110445

Authors: Ioanna Arvaniti Niki Evelpidou Anna Karkani François Sabatier

This study investigates the impacts of Posidonia oceanica (hereinafter P. oceanica) meadows on the coastal morphodynamics of Navarino Bay, Greece, and their role in mitigating coastal erosion. To achieve this, we employed the MIKE 21/3 Coupled Model FM to conduct hydrodynamic and morphodynamic simulations. The study compares two scenarios, one with and one without the presence of P. oceanica, to assess its impact on sediment stability and shoreline protection. Field data, including bathymetric and coastal morphology metrics, were integrated with wind and wave statistics from the Poseidon system. Advanced geospatial tools (ArcGIS Pro) and numerical modeling were used to simulate wave dynamics, current speeds, and sediment transport over a one-year period. Our findings indicate that P. oceanica reduces current velocities and wave energy, leading to enhanced sediment stabilization and reduced erosion rates. This research emphasizes the geomorphological significance of P. oceanica as a protective measure and a nature-based solution (NBS) for addressing coastal management challenges. Our results underscore the need for sustainable practices to maintain the integrity of Mediterranean seagrass meadows amid rising environmental pressures.

Geosciences doi: 10.3390/geosciences16110444

Authors: Daniele Cirillo Emilia Le Pera Francesco Brozzetti Lucia Marinangeli Anna Chiara Tangari

Sedimentary basins are fundamental archives of Earth’s geological evolution, recording the interactions among lithospheric deformation, subsidence, sediment production and dispersal, and surface processes [...]

Geosciences doi: 10.3390/geosciences16110443

Authors: Angelo Doglioni Lorenzo Di Taranto Antonio Fiorentino Giovanni B. Crosta Vincenzo Simeone

The Petacciato landslide is a well-known, very large landslide located along the Adriatic coast of central–southern Italy and involving Plio-Pleistocene marine clay sequences with sandy intercalations. Reactivations have been documented since the early twentieth century and have occurred predominantly after prolonged rainfall periods. On 7 April 2026, a new reactivation event provided an opportunity to investigate this complex landslide system further. Displacements affected the A14 motorway and the Adriatic railway and led to the declaration of a national state of emergency. This study integrates geological, geomorphological, and hydrological information with recent European Ground Motion Service (EGMS) remote-sensing data and precipitation analyses to improve the understanding of the phenomenon. The findings indicate that the Apennine thrust front acts as a structural predisposing factor for the deep-seated landslide, whereas prolonged rainfall triggers reactivation. The analysis highlights the role of long-term cumulative rainfall as a primary driver of reactivation and the value of InSAR monitoring for evaluating continuous ground deformation, including during apparently dormant periods. The results emphasise how reactivation events can improve understanding of landslide behaviour and inform risk-management strategies.

Geosciences doi: 10.3390/geosciences16110442

Authors: Omar Rafeek Mohd Shahrizal Ab Razak Zed Zulkafli Nik Norsyahariati Nik Daud

Predicting permeability from electrical measurements enables non-invasive subsurface hydrogeophysical characterisation. However, the widely adopted Archie–Kozeny–Carman framework relies on empirical assumptions that oversimplify pore geometry and may fail to adequately represent heterogeneous porous media, potentially leading to biased permeability estimates that are inconsistent with the underlying transport physics. In this paper, we derive, from the Navier–Stokes equations and Ohm’s law, a closed-form model that describes permeability as a function of electrical conductivity and pore geometry. The new model uncovers four distinct electrical transport paths in porous media, of which only one aligns mechanistically with fluid-flow trajectories. This distinction provides a physical explanation for the non-unique relationship between electrical conductivity and permeability. The new model is benchmarked against ten widely used permeability models on a global dataset of 6288 laboratory samples, where it achieves superior predictive accuracy (R2 = 0.70; RMSE = 0.47, MAE = 0.34, bias < 0.01, all in log10 m2), remains stable across soil textures, and stays skilful (R2 > 0.60) under data uncertainties of up to 47%, as performed by Monte Carlo simulations. By contrast, predicting permeability from pore-area alone can produce errors spanning several orders of magnitude. This work offers a physically consistent alternative to empirical approximations for predicting permeability.

Geosciences doi: 10.3390/geosciences16110441

Authors: Gökhan Ekincioğlu Yarenkür Alkan Mikail Demirkol Alper Gölbaş İlkay Kaydu Akbudak Zeynel Başıbüyük Hilal Dokuz

The Büyükteflek Roman Bath, located near the Çiçekdağı district of Kırşehir in Central Anatolia, represents an important example of Roman public architecture that reflects both engineering traditions and local material utilization practices. This study investigates the architectural characteristics, geological context, and building materials of the bath complex through an integrated archaeological and geological approach. The structure, dated to the 2nd century AD, exhibits the typical spatial organization of Roman bath architecture, including the apodyterium, frigidarium, tepidarium, caldarium, and a hypocaust heating system. Architectural observations indicate that the hydraulic and thermal systems were designed according to established Roman engineering principles. Field observations reveal that the construction materials consist of a diverse assemblage of lithologies, including ultramafic, volcanic, magmatic, and sedimentary rocks, together with brick and marble elements used in different functional zones of the building. Hypocaust structures and high-temperature areas are predominantly constructed with sandstone and brick, while marble was mainly used as floor and pool lining in water-contact zones. A distinctive feature of the Büyükteflek Bath is the use of large gypsum blocks in certain wall sections. Considering the relatively low mechanical strength and high porosity of gypsum compared with commonly used Roman building stones such as marble or travertine, its use as a construction material is unusual. This choice appears to be closely related to the local evaporitic geology of the region and reflects the pragmatic use of locally available resources in Roman construction practices. Archaeological evidence also indicates that the building experienced significant functional transformations during Late Antiquity. Parts of the bath complex were reused as a small church and burial area, demonstrating the transition of the structure from a secular public facility to a religious space. Anthropological data from the associated burials further suggest that the cemetery was likely used by a socially restricted group. The Büyükteflek Roman Bath thus provides valuable insight into the relationship between Roman architectural traditions, local geological resources, and long-term building reuse processes. The results highlight the importance of considering both material properties and post-excavation environmental conditions in the conservation of archaeological structures constructed with evaporitic stones.

Geosciences doi: 10.3390/geosciences16110440

Authors: Kai Li Aibing Zhang Minyi Zhu

Understanding how clay content alters force transmission and particle rearrangement is essential for explaining the shear behavior of sand–clay mixtures. Laboratory simple shear tests and three-dimensional discrete element simulations were conducted on clean sand and mixtures containing 10%, 20%, 30%, and 40% clay. After calibration against the laboratory shear responses, the simulations were used to track contacts, force transmission, and particle rearrangement. Increasing clay content raised the coordination number but reduced the proportion of sand–sand (S–S) contacts. Despite their declining number, S–S contacts retained a disproportionately large share of the summed normal contact force and a higher force-to-contact ratio than sand–clay (S–C) and clay–clay (C–C) contacts. As clay content increased, force transmission shifted from a predominantly sand-based skeleton toward greater participation of S–C and C–C contacts, while shear resistance decreased. Non-affine displacement was concentrated mainly in the lower part of the specimens, with larger departures from locally affine motion during the earlier shear interval. Together, these observations relate the differences in shear response among the mixtures to changes in contact structure, normal-force distribution, and localized particle rearrangement.

Geosciences doi: 10.3390/geosciences16110439

Authors: Nikita S. Kasatkin Lidiia P. Kasatkina Irina V. Talovina Vyacheslav V. Akinin

Granitoid plutons widespread in the Northern Okhotsk region reflect the main stages of tectonomagmatic evolution of the Koni–Pyagin segment of the Northeast Asian Paleo-Pacific margin. We present new zircon U–Pb geochronological and geochemical data including whole-rock major and trace-element analysis. Our U–Pb ages indicate three main stages of granitoid magmatism: Permian (Aichan complex, ca. 287–260 Ma), Early Cretaceous (Kongali complex, ca. 125 Ma), and Albian–Cenomanian (Magadan and Svetlaya complexes, ca. 107–104 Ma and ca. 101–95 Ma, respectively). These stages correspond to the formation of the Koni–Taigonos arc system, the Uda–Murgal and the Okhotsk–Chukotka volcanic belts. The studied rocks generally show calc-alkaline, subduction-related geochemical characteristics, although systematic compositional differences indicate variations in magma generation and evolution. Granitoids of the Svetlaya complex are characterized by adakite-like geochemical features such as higher Sr/Y and La/Yb ratios. Changes in the rate of magmatic activity from the Early Cretaceous to Late Cretaceous with the magmatic lull at 122-108 Ma reflect arc reorganization of the Paleo-Pacific margin during its long-term evolution.

Geosciences doi: 10.3390/geosciences16110438

Authors: Tumen Darzhokov Adel Sarsenova Abdulakhat Ismailov Aitbek Akhmetzhanov Denis Starikov

Shallow supra-salt oils in the Precaspian Basin change with depth, but the controls are rarely tested. This study aims to quantify the vertical contrast in oil properties at Uytas on the south-eastern basin margin, separate its thermal and compositional parts, and identify what controls the formation waters, using ten oil and fifteen water analyses from twelve wells. The 24.0–28.0 °API oils are medium-gravity crudes, viscous in place because the reservoirs are cold. Estimated dead-oil viscosity at reservoir temperature is 234–764 mPa·s in the Lower Cretaceous and 83–112 mPa·s in the Jurassic, with no overlap in density, viscosity, saturates or aromatics (exact permutation p = 0.0048–0.0095). At a common 20 °C the 4.52-fold contrast falls to 2.40, so it is partly thermal. Only salinity separates the waters (7.4–31.4 against 46.1–94.9 g L−1), consistent with recharge in the Cretaceous and dissolved halite in the Jurassic. Regional evidence points to one oil family from sub-salt Palaeozoic source rocks; the remaining contrast is consistent with mild alteration of the shallow oils, which molecular and isotopic analyses can distinguish from multi-stage charge. Needing only routine appraisal data, the approach suits supra-salt fields across the Precaspian Basin and small fluid datasets in other salt basins.

Geosciences doi: 10.3390/geosciences16110437

Authors: Hamdy Hamed Abd El-Naby Yehia Hassan Dawood Abduallah Abdel Aziz Sabtan

The Jabal Sayid metavolcanic succession in the western Arabian Shield records Neoproterozoic arc magmatism and hosts a major VMS Cu-Zn-Au deposit in Saudi Arabia. This study investigates 31 volcanic samples, ranging from basalt to rhyolite, using petrography and whole-rock geochemistry to evaluate their petrogenesis, evolution, tectonic setting and metallogenic significance. The studied rocks belong to a subalkaline, calc-alkaline suite and show geochemical features typical of a subduction-related volcanic arc, including LREE enrichment, negative Eu and Nb anomalies, and LILE enrichment. Magma evolution was primarily controlled by the fractional crystallization of amphibole, clinopyroxene, plagioclase, and Fe–Ti oxides, although potential contributions from crustal interaction and/or crustal partial melting cannot be excluded. Widespread chloritic, sericitic, silicic, epidotic, and carbonate alteration reflects prolonged hydrothermal activity associated with felsic volcanism and favorable for VMS mineralization. These outcomes indicate that the Jabal Sayid succession formed within a juvenile Neoproterozoic volcanic arc and provide useful geochemical indicators for VMS exploration across the Arabian-Nubian Shield.

Geosciences doi: 10.3390/geosciences16110436

Authors: Leila Abbasian Zijian Li Stephen D. Butt

Borehole Ground-penetrating radar (GPR) is a promising technique for high-resolution geophysical imaging; however, water present in the borehole significantly affects electromagnetic (EM) waves, reducing imaging depth and resolution. Displacing borehole water with an EM-compatible imaging fluid improves borehole GPR performance. The fluid is developed and optimized through comprehensive compositional, electromagnetic, rheological, and numerical investigations. The fluid consisted of canola oil as the base fluid, stearic acid as the suspension stabilizer, and barite as the weighting agent. Barite sources and particle sizes, preparation procedures, and fluid properties were evaluated. Finite-difference time-domain (FDTD) simulations in gprMax compared air-, water-, and EM-fluid-filled boreholes using a 500 MHz source and reflections from a quartz vein and a perfect electric conductor (PEC) cylinder. The results demonstrated that a high-purity and micro-sized barite powder improved suspension stability and electromagnetic compatibility, while the oven-assisted preparation method produced the most stable formulations. Rheological analysis showed that the Herschel–Bulkley and Robertson–Stiff models provided the best agreement with experimental data. In the simulations, the water-filled borehole reduced quartz-vein and PEC-cylinder reflection amplitudes to 12% and 13% of their respective air-filled values, whereas the imaging-fluid-filled borehole produced amplitudes of 108% and 107%, respectively. Laboratory experiments demonstrated that the imaging fluid preserved electromagnetic wave propagation characteristics and improved target detectability compared with water-filled boreholes. These results support further evaluation of the imaging fluid for improving target detectability in borehole GPR investigations.

Geosciences doi: 10.3390/geosciences16110435

Authors: Paola Manzari Giovanni Fanelli Nicola Melone Giovanna Agrosì

We present new petrographic and mineral–chemical data on the Antarctic EL3 enstatite chondrite Elephant Moraine 90299 (EET 90299), obtained by optical microscopy, scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and electron microprobe analysis (EMPA-WDS). EET 90299 preserves well-defined chondrule textures—barred pyroxene, radial pyroxene, porphyritic olivine–pyroxene (POP), and layered chondrules—together with brecciated clasts, showing substantial preservation of chondrule microstructures. The silicate assemblage is dominated by highly magnesian low-Ca pyroxene (Fs 0.7–2.1 mol%). Rare olivine crystals—average Fa 0.33 mol%—found in a POP chondrule are reported for the first time in EET 90299. Chondrule mesostasis shows compositional variability, from predominantly Na–Al and Si-rich to Ca-Na-Al, documenting chemical heterogeneity at the chondrule scale. A euhedral plagioclase crystal identified outside a chondrule displays heterogeneous Na–Ca distribution. The opaque phases comprise kamacite, schreibersite, alabandite, and troilite showing variable Cr contents (2.84 ± 1.07 wt%). The presence of metal–sulphide–silicate intergrowths (MSSI) whose origin remains ambiguous, indicates highly reduced conditions. Opaque-filled micro-veinlets and a wider opaque-rich vein document localized brittle deformation and concentration/redistribution of opaque phases, without pervasively disturbing the primary chondritic texture. Overall, EET 90299 documents the coexistence of well-preserved unequilibrated textures and localized secondary features, providing new micro-scale insights into EL3 chondrite evolution.

Geosciences doi: 10.3390/geosciences16110434

Authors: Kha Xuan Nguyen An Viet Nguyen Tuan Nguyen Xuan Mai Huu Thai Ba Ngoc Thanh Quoc Truong

Predicting fracture architecture away from wells remains a major challenge in crystalline basement reservoirs because hydrocarbon storage and fluid flow are controlled predominantly by heterogeneous secondary fracture networks. This study evaluates whether an exposed granitoid block can provide a useful structural analogue for a deeply buried fractured-basement reservoir through integration of field fracture mapping at Ke Ga, borehole image and conventional well-log data from Well BH-415 in the Bach Ho field, multi-mineral petrophysical modelling, and seismic attributes in the Cuu Long Basin, offshore Vietnam. Three principal fracture populations were identified at Ke Ga, dominated by a NNE–SSW-oriented set striking approximately 20–30° and representing about 57% of the mapped fractures. The BH-415 basement contains vertically variable NNW–SSE, NNE–SSW, NE–SW, and NW–SE fracture trends associated with contrasting degrees of brecciation, alteration, and secondary pore development. The highest-quality fractured intervals exhibit net secondary porosity of up to approximately 6.6% and net permeability exceeding 1100 mD. Cross-scale comparison reveals partial rather than one-to-one structural correspondence: the dominant NNE–SSW Ke Ga population is compatible with NNE–SSW to NE–SW trends in BH-415, and a NW–SE population occurs in both datasets, whereas other subsurface fracture trends lack clear outcrop equivalents. RAI-derived seismic attributes further show spatial consistency with structurally heterogeneous intervals identified at the well. These results demonstrate that fracture orientation alone is insufficient to predict reservoir quality and that outcrop observations should be used primarily to constrain plausible structural architectures rather than to transfer petrophysical properties directly to the subsurface. The integrated workflow provides a conservative cross-scale framework for characterizing heterogeneous fractured crystalline basement reservoirs and evaluating the applicability of surface structural analogues in subsurface exploration.

Geosciences doi: 10.3390/geosciences16110433

Authors: Minglei Liu Di Lu Hui Li Yunlong Zhang Heshan Yang Guoliang Liu Yuhui Feng Nan Ju Pengge Zhang

More than 300 m of core from 18 wells, 4931 m of fullbore electrical image logs from 11 wells, and 3D seismic data were integrated to characterize fracture distribution in Carboniferous volcanic reservoirs of the Dinan Uplift, Junggar Basin. Five eruptive cycles, seven stages, and three volcanic-edifice types were identified. Thirty-three volcanic-edifice intervals from 10 wells (4052 m) were compared by structural position, fault distance, volcanic-edifice type, and facies-belt position. Tectonic fractures strike NW-SE to NNW-SSE and are parallel to reverse faults, with hanging-wall intervals showing a narrower orientation range than footwall intervals. Fracture line density (Dline) is weakly related to fault distance, with R2 values of 0.03 and 0.24 for hanging-wall and footwall intervals, and this relationship differs among volcanic-edifice types. Lava-plateau edifices have the highest pooled Dline, whereas pyroclastic-cone edifices show the largest proximal–distal contrast. Core data indicate higher fracture densities in lavas and coarse heterogeneous pyroclastic rocks than in fine tuffs. Later reverse-fault deformation is expressed more consistently in fracture orientation than abundance, whereas fracture abundance varies among volcanic-edifice, facies-belt, and lithologic settings. Fracture distribution is therefore best understood by considering fault-related structural position together with inherited volcanic architecture rather than by applying a uniform distance-to-fault relationship.

Geosciences doi: 10.3390/geosciences16100432

Authors: Michel Faure Stéphane Scaillet Hugues Raimbourg Clément Montmartin Mathieu Soret Florian Duval

This study combines Raman Spectroscopy on Carbonaceous Matter (RSCM) thermometry and 40Ar/39Ar dating to constrain the thermal structure of the Variscan Para-autochthonous Unit (PAU) in the southern French Massif Central. The RSCM data define a regionally uniform peak-thermal pattern at TRSCM = 535 ± 50 °C throughout much of the PAU that coincides with P-T thermodynamic modeling of Grt-bearing metapelite indicating 525 ± 20 °C and 0.45 ± 0.05 GPa. This pattern post-dates thickening. No RSCM temperature increase can be seen around late granitic plutons, presumably as a consequence of unfavorable transformation kinetics. In contrast, 40Ar/39Ar step-heating dating of syn- and post-folial muscovite and biotite populations record regional N-S variations from 330 Ma to 325 Ma, down to 305 Ma around plutons. In pluton contact aureoles, 40Ar/39Ar systematics appear controlled by synkinematic recrystallization at 315–300 Ma, indicating a continuum of P-T variations during pluton emplacement. Older biotite and muscovite ages at 325 Ma record an early deformation stage predating regional muscovite ages between 320 and 315 Ma. In the eastern PAU, 332–322 Ma ages argue for an early thickening event. The decoupling between regional 40Ar/39Ar variations and the RSCM temperature record indicates that the thermal regime was associated with a late-thickening thermal event.

Geosciences doi: 10.3390/geosciences16100431

Authors: Junxing Ren Wenchao Shao Yang Wang Yue Zhuo Huiguang Hu Zhenjia Cai

Key stress thresholds—crack initiation stress (Ci), crack damage stress (Cd), and peak strength (Cp)—delineate the progressive stages of crack development, yet their utility for characterizing rock damage in unconventional reservoirs remains insufficiently explored. This study investigates rock damage behavior using triaxial compression failure tests on three tight sandstones and seven shales. Ci, Cd, and Cp are determined via the lateral strain response method, volumetric strain reversal, and peak deviatoric stress, respectively. The normalized ratios Ci/Cp and Cd/Cp are introduced as descriptors of crack initiation and damage acceleration timing. Three damage modes emerge: Group 1 (high Ci/Cp > 0.65, Cd/Cp > 0.9) is brittle, with prolonged elasticity and sharp post-peak failure; Group 3 (low Ci/Cp < 0.5, Cd/Cp < 0.75) is ductile-dominated, with early cracking and gradual stress decline; Group 2 represents a mixed mode. Strain energy analysis corroborates the classification—brittle samples retain Ue/U > 0.75 at peak stress, while ductile samples develop Ud/U of 0.4–0.5. Two conventional brittleness indices can identify highly brittle rocks but fail to distinguish mixed from ductile modes. In contrast, Ci/Cp and Cd/Cp reliably capture damage evolution across the full failure process, offering a physically grounded framework for hydraulic fracturing target selection in unconventional reservoirs.

Geosciences doi: 10.3390/geosciences16100430

Authors: Alejandro Duitama Leal Luis A. Montes Vides Héctor J. Hortúa Orjuela Luis A. Castillo López

This study presents a probabilistic deep learning framework developed for full waveform inversion (FWI) to detect and characterise subsurface velocity anomalies induced by stored CO2. Three convolutional neural network architectures—LinkNet, UNet, and a feature pyramid network (FPN)—were trained and evaluated on the Kimberlina CO2 synthetic dataset from the OpenFWI repository, which simulates CO2 injection scenarios within stratified reservoirs. The FPN architecture with an SE-ResNet50 backbone achieved the best performance (R2=0.9386, MSE=3.1676×10−4, MAE=4.5249×10−3). Uncertainty quantification was performed using variational inference with the Flipout estimator, which enables the separation of aleatoric and epistemic uncertainty. The predicted velocity models accurately reconstruct the background stratigraphy and the low-velocity anomaly associated with the CO2 plume. The aleatoric uncertainty remains at around 101 m/s and is spatially localised to delineate the geometry of the low-velocity zone. In contrast, the epistemic uncertainty is several orders of magnitude smaller, at around 10−3 m/s, and increases specifically over the lowest-velocity region of the anomaly. This structured distribution indicates where the velocity reconstruction is least reliable. Calibration substantially reduced the overall miscalibration area, decreasing the magnitude of the aleatoric component while slightly increasing that of the epistemic uncertainty over the CO2 plume anomaly, although the spatial structure of both components remained unchanged. This uncertainty decomposition and calibration help to distinguish between data noise and model limitations. It provides direct information for designing acquisitions and assessing risks, which is an area that is not widely covered in the current literature.

Geosciences doi: 10.3390/geosciences16100429

Authors: Yetong Wang Shutong Li Xianyang Liu Zhongyi Zhang Ming Shao Junlin Chen Wei Wang

Lithofacies heterogeneity may separate organic matter enrichment from the normalized oil-bearing response of lacustrine shale, complicating the identification of effective shale oil intervals. To examine this relationship, the Chang 9 Member of Well Danye-1 in the Ordos Basin was investigated through core observation, X-ray diffraction (XRD), total organic carbon (TOC) analysis, Rock-Eval pyrolysis, chloroform bitumen “A” extraction, vitrinite reflectance (Ro), scanning electron microscopy, and porosity–permeability measurements. The TOC values range from 0.07 to 9.62 wt.% and average 2.18 wt.%. The interval is thermally mature, with Ro values of 0.85–1.15% and a mean of 0.99%. Mud-rich groups generally contain higher TOC, S1, S2, and chloroform bitumen “A” content, and the positive correlations among these parameters indicate that the organic matter abundance exerts the primary control on the hydrocarbon generation potential and absolute hydrocarbon abundance. However, oil saturation index (OSI) maxima do not consistently coincide with TOC maxima: several samples with TOC above 4 wt.% have only moderate OSI values, while elevated OSI values occur locally in samples containing less than 2 wt.% TOC. The reservoir is generally tight, with porosity of 0.39–5.67% and permeability of 0.000170–0.0630 mD. Mud-rich groups are characterized by higher organic matter richness and hydrocarbon-related geochemical parameters; they contain abundant interlayer pores and organic-related nanopores that favor retention but restrict pore throat connectivity. Silt-rich rocks contain relatively abundant feldspar and locally preserve residual intergranular pores, dissolution pores, and bedding-parallel microfractures, indicating pore morphologies that differ from those observed in mud-rich rocks. The OSI-TOC geochemistry demonstrates that the low residual OSI in organic-rich mudstone reflects efficient hydrocarbon expulsion rather than insufficient hydrocarbon generation. The geological sweet-spot evaluation should therefore integrate hydrocarbon supply, the absolute oil content, and pore network effectiveness instead of relying on TOC or OSI alone.

Geosciences doi: 10.3390/geosciences16100428

Authors: Misael Del Rio Torres Julián González Trinidad Hugo Enrique Júnez Ferreira Efrén González Ramírez José Antonio Rodríguez Rodríguez Ana Isabel Veyna Gómez Ada Rebeca Contreras Rodríguez Osbaldo Navarro Solís Ricardo Robles Ortiz

Mineral scale deposits in groundwater-supplied drinking water distribution systems reduce hydraulic efficiency and increase maintenance costs. This study evaluated the effectiveness of citric acid as a descaling agent for natural scale deposits collected from the Benito Juárez and La Joya drinking water distribution systems in Zacatecas, Mexico. The samples were treated with citric acid solutions at concentrations of 1, 2, and 3 M (moles per liter) and characterized before and after treatment using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and inductively coupled plasma optical emission spectrometry (ICP-OES). In addition, statistical analyses were performed using analysis of variance (ANOVA) and Tukey’s test. The scale deposits were composed mainly of calcium carbonate and exhibited differences in their initial mineralogical composition between the two systems. Treatment with citric acid promoted the progressive dissolution of carbonate phases, resulting in mineralogical, chemical, and morphological changes. The 3 M solution produced the highest degree of mineral dissolution, whereas the 1 M and 2 M treatments showed statistically similar behavior. The results demonstrate that scale deposit removal efficiency is influenced by the initial composition of the scale deposits, providing a scientific basis for optimizing remediation strategies in drinking water distribution systems.

Geosciences doi: 10.3390/geosciences16100427

Authors: Yuxuan Chen Fuqiong Huang Leyin Hu Zhiguo Wang Kongyan Han Peixue Hua Xiaoru Sun Mingbo Yang Shijun Zhu Bowen Cui Boxiu Fei Hongyan Dong Shijun Zhong

Establishing the groundwater geochemical background (GGBC) is fundamental for distinguishing seismic precursors from non-tectonic environmental influences. This study characterizes the spatiotemporal evolution of the GGBC in Beijing using 60 groundwater samples collected from 17 seismic monitoring wells between 2018 and 2025. Major ion concentrations, stable water isotopes (δ2H and δ18O), Self-Organizing Map (SOM) clustering, Principal Component Analysis (PCA), ionic ratios, and mineral saturation indices were integrated to analyze the hydrochemical framework for establishing the GGBC baseline. Piper diagram results reveal three main hydrochemical types: Na·HCO3 type, Ca·Mg·HCO3 type, and sulfate type (subdivided into Na·SO4 and Ca·Mg·SO4/HCO3 subtypes). Hydrogen and oxygen isotope data from 2024 indicate that recharge sources range from deep bedrock fissure water to shallow mixtures of meteoric and surface water. Gibbs diagrams, SOM, and PCA consistently demonstrate that water–rock interaction (including carbonate, silicate, and evaporite dissolution, as well as cation exchange) dominates the GGBC. Ionic ratios and saturation indices further confirm that silicate weathering and forward cation exchange are persistently widespread, while carbonate and evaporite dissolution are locally important. Notably, 12 wells of the 17 monitoring wells (71%) retained the same hydrochemical type across all campaigns in which they were sampled. This stability shows no detectable temporal correspondence with either the V-shaped pattern of seismic activity (strong–weak–strong, 2018–2025) or the regional groundwater level rise caused by water diversion projects at the available annual-to-multi-year sampling resolution. Instead, the high stability of the GGBC reflects long-term water–rock equilibrium that is resilient to minor, transient perturbations. This study demonstrates that major ions are reliable indicators of the GGBC for assessing the sensitivity of the Beijing Plain to short-term seismic or hydrological disturbances. However, the limited temporal resolution of the sampling and incomplete datasets preclude definitive conclusions regarding earthquake-related geochemical signals. To strengthen regional earthquake monitoring and forecasting capabilities, we recommend establishing a continuous, long-term, high-frequency, multi-parameter monitoring network—including stable isotopes, trace elements, and dissolved and exsolved/free gases—with high data completeness in the Beijing area.

Geosciences doi: 10.3390/geosciences16100426

Authors: Saurabh Singh Ashwani Raju Ascanio Rosi Ramesh P. Singh Sanjeet Kumar Mario Floris Sansar Raj Meena

Precise assessment of landslide potential in tectonically active mountainous areas like the Darjeeling Sikkim Himalaya (DSH) is a scientific challenge because of the complexity of the terrain and the factors controlling landslides. Despite several studies on landslide susceptibility mapping in the DSH, most conventional pixel-based approaches struggle to demarcate the geomorphological units and complex nonlinear relationships among the landslide conditioning factors. Furthermore, incomplete landslide inventories can also hamper landslide susceptibility assessment quality. Due to all these limitations, more robust methods integrated with geomorphologically based terrain segmentation and advanced machine learning methods are required, which will not only determine the landslide probability zones but also help to understand the landslide driving forces and interaction analysis among the geoenvironmental factors controlling landslides. In the present study, we have used slope unit-based landslide susceptibility mapping, using 4830 slope units, 17 conditioning factors and 8373 of the total updated landslide inventories with six models: random forest (RF), a generalized additive model (GAM), Categorical Boosting (CatBoost), Tabular Neural Network (TabNet), Bayesian additive regression trees (BARTs), and a convolutional neural network (CNN). The model hyperparameters were optimized using Bayesian optimization, except for the BART model. Based on the area under the receiver operating characteristic curve AUC value, RF (AUC = 0.848), BART (AUC = 0.847) and CatBoost (AUC = 0.846) achieved the highest predictive performance. Furthermore, SHAP based analysis shows that most of the landslides are controlled by elevation, aspect, slope, distance to faults, NDVI, proximity to roads and drainage networks. Whereas the SHAP-based interaction analysis shows that most of the landslides are controlled by non-linear, threshold-dependent relations, especially between slope rainfall, rainfall soil moisture, slope distance to roads and fault, which represents a complex interaction between the hydrological factors, geomorphic processes, tectonic activity and human interventions. This study can be used for disaster risk reduction and regional infrastructural planning in DSH.

Geosciences doi: 10.3390/geosciences16100425

Authors: Joan Manuel Flores López Aderson Farias do Nascimento

This study demonstrates the application of passive seismic interferometry, specifically through single-station autocorrelation, to extract high-resolution P-wave reflections from seismic data acquired during hydraulic fracturing. Using 10 h of continuous passive records from the Potiguar Basin, NE Brazil, we applied a processing sequence comprising a Gaussian smoothing filter and spectral whitening to eliminate source distortions and recover the empirical Green’s function. The resulting zero-offset seismic sections, constructed in 2D and projected into 3D, reveal continuous, coherent reflectors down to 2 s two-way travel time. While deeper reflectors correlate closely with legacy active-source profiles and regional geology, direct validation of the shallowest interfaces (<500 m, corresponding to Cenozoic cover and the upper Jandaíra Formation) remains interpretive due to the lack of local borehole or high-resolution shallow geophysical control in the uppermost 300 m. Additionally, Rayleigh-wave dispersion analysis from cross-correlations yielded an S-wave velocity model for the shallowest 180 m (Vs ≈ 1350 m/s), constrained by the maximum available array offset of 1450 m. These results highlight the efficacy of hydraulic fracturing-induced noise as a high-frequency source for exploration-scale reflectivity imaging, providing a non-invasive, potentially cost-effective tool to complement active seismic campaigns.

Geosciences doi: 10.3390/geosciences16100424

Authors: Laura Lamair Aurélia Hubert-Ferrari Hervé Degée Volkan Karabacak Hélène Dessales Julia de Sigoyer Hatice Pamir

Roman aqueduct bridges are widespread across the seismically active Mediterranean, but their seismic response in areas of very high seismicity remains poorly documented. Here, we present a first-order numerical investigation of the in-plane seismic response of these structures and apply the approach to plausible structural states of the Antioch-on-the-Orontes aqueduct at Harbiye (Antakya, Türkiye), in a region affected by the 6 February 2023 Mw > 7 earthquake sequence. The monument records several construction phases, repairs, and partial collapses. We use modal and linear time-history analyses of simplified 2.5D arch-and-pier finite-element models, with recorded historical ground motions applied in the longitudinal plane of the structures. We test the influence of pier height, arch width, deck thickness, reinforcement, stiffness, Poisson’s ratio, and density. The models repeatedly show stress concentrations at the arch springings and pier bases. Higher piers, wider arches, thicker decks, lower stiffness, and greater structural mass increase the calculated response, whereas buttresses, larger piers, and lower density reduce it. In the Antioch models, several zones of high calculated elastic demand coincide with observed damaged, collapsed, or repaired sectors, and the reinforced configuration shows lower stress concentrations than the comparable unrepaired one. A literature-based benchmark shows that the calculated Harbiye modal frequencies are of the same order of magnitude as experimentally identified frequencies reported for comparable masonry aqueducts and historical arch structures. However, no experimental dynamic characterization is available for Harbiye, and the monument-specific models have not been calibrated or validated. The results should therefore be interpreted as preliminary estimates of plausible first-order response patterns rather than as a quantitative seismic assessment of the existing monument.

Geosciences doi: 10.3390/geosciences16100423

Authors: Enrique Sánchez Miguel Ángel Gaertner Clemente Gallardo Manuel de Castro

Regional climate models (RCMs) have become established as essential dynamical downscaling tools, providing physically consistent, high-resolution climate information where global climate models (GCMs) are unable to resolve. Added value is obtained over heterogeneous vegetation, coastal, urban or orographically complex zones. Temperature, precipitation or wind benefit whenever fine-scale processes govern the climate signal, as with extreme events. CORDEX initiative (since 2009) has further consolidated RCM research with coordinated multi-model ensembles covering all continental regions, enabling systematic uncertainty quantification of regional climate projections. PROMES RCM has been an active scientific contributor across three decades to the modelling community ensemble, with operations discontinued around 2015. This retrospective narrative review synthesizes and documents PROMES’s development, performance across Europe, West Africa and South America, and assesses its scientific contributions. This includes climate change projection features, extreme events (droughts, heat waves, or Mediterranean tropical-like cyclones) or land surface–atmosphere studies. Its behaviour within the more relevant international multi-model ensembles (from PRUDENCE to EuroCORDEX), with structurally independent characteristics, represents a scientific asset for uncertainty characterization beyond the model’s individual results, offering a legacy argument for preserving RCM diversity in ensemble design strategies, as it is an essential and many times underappreciated key point of uncertainty analysis.

Geosciences doi: 10.3390/geosciences16100422

Authors: Xiao Ma Tariq Alkhalifah

Time-lapse (4D) seismic inversion is a key tool for monitoring subsurface changes caused by fluid injection and production, but model-based workflows require repeated forward and adjoint evaluations, a wavelet estimate for every vintage, and survey-specific regularization tuning. We propose a 3D neural operator framework for post-stack time-lapse impedance inversion. A U-shaped neural operator is trained on synthetic impedance models and their convolutional post-stack responses and serves as a mesh-independent, differentiable surrogate of the post-stack forward operator. During inversion, the operator is frozen, and the impedance model is updated by gradient descent with automatic differentiation using one set of settings for all vintages of a survey. On the Kimberlina synthetic CO2 model, the inversion reduces the error of the initial model for every vintage (relative error from 3.1–3.2% to 2.8–2.9%). On the Sleipner field data, the recovered impedance changes are concentrated inside an independently mapped CO2 plume (median change 4.7–7.3 times larger than outside), the predicted 4D data difference correlates with the observed one at r=0.92–0.93 inside the plume, and the operator is applied without retraining to the full 1001×468×249 survey grid. We also quantify the training and fine-tuning costs and discuss the limits of a learned convolutional surrogate.

Geosciences doi: 10.3390/geosciences16100421

Authors: Zhen Zhang Keyang Hu Xiaohui Ji Mei Yang Bo Xu Guocheng Lv Shan Zeng Jiaxue Li

Deep learning-based mineral image recognition from macroscopic hand-specimen photographs has emerged as an important approach for mineral identification. However, the inherent imbalance in the natural distribution and reserves of minerals leads to a long-tailed distribution in mineral image datasets, resulting in significantly lower recognition accuracy for minerals with fewer images. To address this issue, we propose a multi-stage training framework that enhances the recognition performance of tail-class minerals through feature extractor adjustment, core feature learning, and classifier re-training. Feature extractor adjustment increases the logit scores of tail-class samples, core feature learning increases the sampling frequency of low-confidence instances, and classifier re-training increases the classifier’s sensitivity to tail-class instances. The multi-stage training framework improves the overall performance of mineral recognition and strengthens the model’s generalization ability. Experimental results on a dataset of 36 mineral categories demonstrate that the proposed method increases the mean accuracy of the one-third mineral species with the least amount of data from 67.47% to 80.06%, with a maximum improvement of 24.1%. Moreover, the overall mean accuracy across all 36 mineral categories increases from 77.27% to 81.27%, confirming the effectiveness of the proposed approach.

Geosciences doi: 10.3390/geosciences16100420

Authors: Chamidu D. B. Acharige Dunja Perić

Energy piles are multifunctional deep foundations that structurally support buildings while enabling heat exchange between the superstructure and shallow subsurface. It is crucial for the wider use of energy piles and thus reliance on clean, renewable shallow geothermal energy for supplemental space heating and cooling to understand thermal and combined thermo-mechanical load transfer. To this end, previously developed and successfully validated analytical solutions are transformed into a unified dimensionless form, and the minimum set of controlling composite parameters is identified through rigorous application of the Buckingham Π theorem. A multifaceted solution space is explored through a sensitivity analysis performed across a wide range of controlling parameters and under different boundary conditions. The results show that the mechanisms of load transfer for thermal and mechanical loads are inherently different. In a very stiff soil, mechanical load is supported by the soil, while thermal load generates significant stress in the pile. Thus, the thermo-mechanical stress response is dominated by the thermal response. In a very soft soil, mechanical load is supported by the pile while stresses generated by thermal load are negligible. Thus, the thermo-mechanical stress response is dominated by the mechanical response.

Geosciences doi: 10.3390/geosciences16100419

Authors: Quanrui Liu Kegang Li Mingliang Li Zhiqiang Qiao Xiaofei Liu

To investigate the influence of joint spatial orientation on the rockburst mechanism of deep roadways, this study employs a true triaxial rockburst testing system to conduct physical simulation experiments on three types of limestone specimens from Yunnan: joint-free, parallel-jointed, and vertical-jointed. By integrating multi-source data acquisition techniques including high-speed imaging, acoustic emission (AE) monitoring, and fragments sieving, this research systematically analyzes the macroscopic failure process of rockburst, the evolutionary patterns of AE signals, and the characteristics of fragment generation under different fracture configurations. Joint orientation critically governs the rockburst failure mode, with parallel joints promoting extensive spalling and vertical joints localizing damage. Parallel joints act as guiding weak planes, resulting in a wider and more intense failure range, while vertical joints cause localized failure. The characteristics of acoustic emission signals reveal the regulatory mechanism of joints on the AE energy accumulation and release process. The parallel-jointed specimens exhibit a “step-like” increase, reflecting their phased damage and stress redistribution. Quantitative analysis of fragments indicates that the total mass of fragments in the parallel joint specimens is the largest, and the fractal dimension is the highest, indicating the most thorough fragmentation. This research provides crucial experimental evidence for the precise identification and differentiated prevention and control of rockburst risks in deep jointed rock mass engineering. It should be noted that these findings are derived from exploratory laboratory comparisons based on one specimen for each joint configuration, and further repeated tests are required to verify the generalizability of the observed patterns.

Geosciences doi: 10.3390/geosciences16100418

Authors: Giorgio Alaia Angela Bertinelli Angela Baldanza Regina Lupi Luca Pasqualone Maurizio Ercoli

An integrated petrographic–geophysical workflow is applied to the Castellina Fortress (16th century AD) to investigate: the masonry texture, construction techniques and lithological provenance. The field activities focused on several architectural structures of the Castellina, including the main façade that was embedded inside the fortress out of a previous building, named Podestà Palace (13th century AD). The petrographic analyses document the use of lithoid limestones from the Maiolica, Scaglia Bianca and Scaglia Rossa Formations (Umbria–Marche Stratigraphic Succession) in the Podestà Palace, while limestone breccias can be mainly found in the cloister columns. The Ground-Penetrating Radar (GPR) data, supported by advanced numerical modelling, show a heterogeneous internal texture in the Castellina Fortress related to the use of both lithoid materials and earthquake-derived debris for the columns. The provenance analysis points out that the limestones were quarried from Monte di Colle, Monte Belvedere and Monte Poggio Vallaccone (southeast of Norcia), whereas the breccias largely derived from debris cones composed of breccia, gravel, and conglomerate deposits that still crop out today in the mountainous area surrounding the plains of Norcia and Santa Scolastica. This study demonstrates the potential of combining two different geoscience disciplines to reconstruct material supply zones and building characteristics in the field of cultural heritage.

Geosciences doi: 10.3390/geosciences16100417

Authors: Michelangelo Bisconti Mark Bosselaers

Right and bowhead whales represent key species in modern-day marine ecosystems because of their capacity to catch enormous amounts of prey items (especially calanoid copepod crustaceans). However, their evolutionary history is still not completely understood. Morphology- and molecule-based phylogenetic analyses failed to find a consensus view about the relationships of balaenids and other mysticete species and in determining the intra-family relationships of extant and fossil taxa. The fossil record may help in increasing the precision of morphology-based phylogenetic results when new balaenid species are discovered because the new fossils may add new character combinations able to change previously published hypotheses of relationships. Here, we describe a new balaenid genus and species, Quasibalaena portisantuerpiae, based on a partial skull from the Early Pliocene of Belgium. The new specimen preserves relevant portions of the cranium, periotic and tympanic bulla, and shows a character combination never observed up to now in other balaenid fossils. We compared the new taxon to all the other balaenid species known and included it in a morphology-based phylogenetic analysis. The results suggest that Balaenidae includes a stem group and two main subclades, respectively related to the extant bowhead whale (Balaena mysticetus) and to the right whales (genus Eubalaena). Quasibalaena portisantuerpiae belongs in the former subclade. Body size reconstruction allowed us to infer that the origin of the Balaena-related clade was characterized by a miniaturization process and that gigantism occurred independently in bowhead and right whales.

Geosciences doi: 10.3390/geosciences16100416

Authors: Yashuang Hu Xiaobo Li Qingchun Yang Robert R. Reisz

Root systems, the hidden half of terrestrial plants, have been a fundamental geological agent since the late Early Paleozoic, with their evolution preserved in a rich but underutilized archive of soils and sediments. This review adopts a rhizolith-centric perspective to trace the co-evolution of root systems and the Earth’s surface environment from the Silurian to the present. Two profound, linked transitions are recognized. The first is the Devonian “Rooting Revolution,” during which true roots and their mycorrhizal partners scaled up silicate weathering, drawing down atmospheric CO2 and contributing to the initiation of the Late Paleozoic Ice Age. The second is the Mesozoic–Cenozoic “Rhizosphere Expansion,” led by angiosperms, which greatly amplified the existing weathering engine through higher transpiration, denser fibrous roots, and more diverse rhizosphere microbial and mycorrhizal communities. Reading rhizoliths through their morphology, mineralogy, and isotopic signatures makes it possible to reconstruct how roots became central regulators of long-term carbon and phosphorus cycling, builders of the pedosphere, and stabilizers of landscapes. Beyond these geochemical roles, this also integrates the dimension of roots as a persistent nutritional resource for terrestrial vertebrates—from Early Permian stem amniotes and early synapsids and reptiles to Pleistocene megafauna and early hominins. By synthesizing evidence from paleontology, sedimentology, geochemistry, and vertebrate paleoecology, this review offers a rhizolith-centric framework—anchored by the two linked transitions described above—for refining Earth system models and for understanding the feedbacks between root evolution and global environmental change.

Geosciences doi: 10.3390/geosciences16100415

Authors: Camilo Antonio Quintero-Tejada Ignasi Herms Marc Gil-Ortiz Jesús García-Crespo Paula Fernández-Canteli

Pressure-limited dynamic capacity in the Lopín structure is controlled primarily by reservoir transmissibility rather than by static pore volume. This study applies a MATLAB/MRST vertical-equilibrium (VE) workflow to the Lopín horst, a deep Triassic Buntsandstein aquifer in the Ebro Basin, NE Spain, and evaluates the sensitivity of the results to seven petrophysical, fluid, and operational parameters using a one-at-a-time sensitivity design (35 sensitivity cases plus one base case). Across the tested range, horizontal permeability produced the largest variation in maximum injectable CO2 mass, from 4.67 to 16.25 Mt (range 11.59 Mt), followed by the adopted BHP threshold (range 5.33 Mt) and CO2 density (range 4.74 Mt). Porosity and brine compressibility had only minor effects, whereas injection rate and residual CO2 saturation did not change the BHP-limited capacity under the adopted capacity-search formulation. The base-case operational BHP limit was 28.5 MPa, selected below the site-specific allowable- and estimated fracture-pressure thresholds reported for Lopín. These results show that pressure dissipation, hydraulic transmissibility, and the explicit choice of operational pressure criterion are the dominant controls on dynamic CO2 storage capacity in this fault-bounded saline aquifer.

Geosciences doi: 10.3390/geosciences16100414

Authors: Shaohan Xie Yuqi Tian Yishi Wang Zhizhou Yang Xuyang Yang Jian Liu Yinke Yang Huan Ma

Projecting runoff and extreme hydrological events in human-modified basins requires climate, land-use and reported water-consumption forcings to be represented within a single, traceable scenario framework. Here, the Dawen River, the largest tributary of the lower reaches of the Yellow River, was selected as the study area. We coupled a physically based model (SWAT model) with the CEEMDAN–Attention–LSTM model to forecast future social water consumption and runoff and then diagnosed extreme hydrological events and decoupled the main driving factors driving runoff dynamics using multiple remote-sensing and hydrometeorological datasets. Five global climate models (GCMs) of the Coupled Model Intercomparison Project Phase 6 (CMIP6) were selected, and the Delta statistical downscaling method was adopted to enhance the future climate data. The GeoSOS-FLUS model was applied to simulate the future LULC distribution, and then all the climate data, the LULC data and other remote-sensing data were input into the CEEMDAN–Attention–LSTM–SWAT model. The results confirmed that the coupled model had reasonable performance in social water consumption and runoff simulation; the Nash–Sutcliffe efficiency (NSE) values for the measured and simulated runoff ranged from 0.80 to 0.84. Future runoff in all scenarios showed varying degrees of increasing trends. Future droughts display longer durations with lower severity compared to floods, while pluvial flood events are characterized by shorter durations with higher severity. The frequency of the drought–pluvial seesaw increased from upstream to downstream in the SSP126, SSP245, and SSP585 scenarios. Finally, the results of decoupling runoff dynamics revealed that the contribution of human activities showed a slight overall increasing tendency from upstream to downstream, accounting for 70% to 82% of runoff alterations, and social water consumption and the LULC factors were the dominant anthropogenic factors.

Geosciences doi: 10.3390/geosciences16100413

Authors: Peiyue Liu Zhanghui An Yingying Fan Yi Lin Yiqiang He Yangning Hou

Seismoelectric responses generated in fluid-saturated porous media contain indirect geophysical information related to subsurface interfaces, material contrasts, and electrokinetic coupling. Many three-dimensional simulations adopt a quasi-static electromagnetic approximation, which neglects displacement-current contributions and cannot provide a complete description of full-wave electromagnetic propagation. In this study, we present a hybrid spectral-element and finite-element time-domain framework for three-dimensional full-wave seismoelectric modeling based on the Pride–Biot equations and the magnetic vector potential–electric scalar potential (A–ϕ) formulation. The poroelastic wavefield is first computed using a high-order spectral-element method, and the resulting relative fluid–solid velocity is introduced as the source term for the electromagnetic problem. An implicit backward-difference scheme is employed to accommodate the substantial difference between seismic and electromagnetic wave speeds. The coupled A–ϕ systems are solved using a flexible generalized minimal residual method with an upper-triangular block preconditioner based on an approximate Schur complement and algebraic multigrid cycles. This solver strategy is adopted as a practical treatment for the large, sparse, nonsymmetric, and strongly coupled systems generated by the three-dimensional formulation. The proposed framework is validated through numerical experiments involving half-space and layered media, a fault damage zone model, and a modified SEG/EAEG salt-dome model. The results reproduce the expected coseismic and interfacial responses and demonstrate the accuracy, numerical stability, and computational feasibility of the method in heterogeneous three-dimensional structures. The framework provides an effective forward-modeling tool for analyzing full-wave seismoelectric responses and for generating synthetic data for future subsurface sensitivity and joint-inversion studies.

Geosciences doi: 10.3390/geosciences16100412

Authors: Bakytgul Agaliyeva Gulizat Orazbekova Baitak Apshikur Olga Frolova Damir Mukyshev Bakytzhan Amralinova Indira Mataibaeva

Remote sensing can support mineral exploration in geologically complex terrains, but distinguishing mineralisation-associated spectral responses from lithological and surficial variability remains challenging. This study presents and evaluates an integrated workflow for delineating and prioritising prospective zones for gold mineralisation at the Suzdal deposit, Kazakhstan. Sentinel-2 imagery was analysed using diagnostic band ratios, unsupervised spectral clustering, principal component analysis (PCA), and reference-signature-based spectral similarity classification. The resulting spectral patterns were integrated with lithological contacts, structural–geomorphological features, residual structures, denudation patterns, and lineaments; the delineated prospective zones were subsequently evaluated using independent exploration-drilling data and supporting geophysical information. PCA highlighted broad multispectral variability, whereas spectral similarity classification provided more spatially explicit delineation of mineralisation-associated surface responses. Higher-priority zones were identified where complementary remotely sensed responses converged within favourable geological–structural domains. Quantitative validation showed that 6 of 7 assay-confirmed Au-positive drill holes occurred within the delineated prospective zones, corresponding to a Spatial Capture Rate (SCR) of 85.7%. The novelty lies in combining deposit-specific geological criteria with complementary Sentinel-2 analyses within a unified targeting framework and subsequently evaluating the resulting prospectivity pattern against independent exploration evidence. The workflow provides a reproducible approach for exploration-target prioritisation at Suzdal and potentially in comparable gold-mineralised settings in Kazakhstan.

Geosciences doi: 10.3390/geosciences16100411

Authors: Shengli Gao Jun Wang Haojie Chen

The Chang 9 interval of the lower Yanchang Formation in the Ordos Basin is an important exploration target. Integrating stratigraphic correlation of 163 wells, sedimentary facies analysis of 10 wells, reservoir testing, and fluid pressure–temperature data, this study investigated reservoir characteristics and the main controlling factors of hydrocarbon accumulation in the Beiliang area of Wuqi. The K0 marker bed allows the Chang 9 Member to be subdivided into Chang 91–93. Delta-front subaqueous distributary channel sandbodies form the principal reservoirs, composed mainly of fine-grained feldspathic and lithic feldspathic sandstone with residual intergranular and dissolution pores. Average porosities are 8.23–9.66%, and permeabilities are 4.28–5.64 × 10−3 μm2, indicating low-porosity, low-permeability, strongly heterogeneous reservoirs. The lithologic reservoirs belong to a normal-temperature, low-pressure system (pressure coefficient 0.78), with CaCl2-type formation water. Hydrocarbons were mainly derived from Chang 7 source rocks, with possible supplementary supply from Chang 9 dark shales. Accumulation is controlled by hydrocarbon supply, subaqueous distributary channel distribution, and reservoir effectiveness and connectivity; low-amplitude nose structures only adjust local oil–water distribution, while traps are mainly lithologic, controlled by updip pinch-out and tight-sand sealing.

Geosciences doi: 10.3390/geosciences16100410

Authors: Li Huang Saiyan Liu Yangyang Xie Yufei Wang Dongyong Sun Dengfeng Liu

Potential evapotranspiration (PET) is a core indicator of atmospheric evaporative demand and plays a critical role in drought dynamics. Yet the characteristics of extreme PET events and their governing mechanisms remain poorly understood. Unlike previous studies that have mainly focused on mean-state PET, this study provides the first systematic identification and attribution of extreme PET events in a representative semi-humid to semi-arid climatic transition zone. This study investigates the spatiotemporal evolution and driving mechanisms of extreme PET in the Wei River Basin, using daily meteorological data from 1975 to 2019, the FAO-56 Penman–Monteith equation, and an adapted thirstwaves identification framework. A three-dimensional indicator system comprising magnitude intensity (MI, severity), temporal intensity (TI, mean duration), and frequency intensity (QI, occurrence frequency) is constructed, and integrated methods including the variance-corrected Mann–Kendall test, wavelet analysis, conditional sensitivity analysis, and cross-wavelet transform are employed. Results reveal that extreme PET exhibits pronounced spatial heterogeneity, with higher intensity in drier northwest and longer duration and higher frequency in the southeast. Trend directions vary substantially across stations, while multi-scale periodic oscillations of 5–15 years are identified. Conditional sensitivity analysis indicates that PET is most sensitive to sunshine duration overall, but its relative sensitivity decreases under extreme conditions, indicating a radiative saturation effect. In contrast, the synergistic enhancement of maximum temperature and wind speed becomes the primary driver pushing PET beyond extreme thresholds, with the strongest synergy in the semi-arid northwestern WRB. PET is more sensitive to relative humidity in the southeastern Guanzhong Plain, while atmospheric pressure has only a weak influence across the basin. Cross-wavelet analysis further shows that ENSO and PDO significantly modulate the cyclic variations of extreme PET, yet their teleconnection signals are attenuated compared to those for average PET. In sharp contrast, the Arctic Oscillation (AO) exhibits negligible influence on the basin’s extreme PET, highlighting the seasonal decoupling of high-latitude atmospheric signals from regional evaporative demand during the growing season. Notably, annual mean PET shows a significant upward trend, whereas extreme PET exhibits no significant trend, indicating that the “evaporation variability increase” hypothesis does not hold in the WRB. This implies that SPEI-based drought monitoring relying on mean PET may not fully capture changes in extreme evapotranspiration. These findings advance the mechanistic understanding of extreme evapotranspiration, highlight the regime shift in relative importance from radiation to temperature-wind synergy under extreme conditions, and provide scientific support for drought adaptation and water resource management in climatically sensitive regions.

Geosciences doi: 10.3390/geosciences16100409

Authors: Sandro Galdenzi

This study investigates the Jurassic successions of the Foligno mountains by tracing tectono-sedimentary contacts across the study area, with particular attention to the relationships between pelagic deposits and the Calcare Massiccio carbonate platform substrate. It provides new constraints on the role of syn-sedimentary extensional faulting in the evolution of the Umbria-Marche Basin. The results reveal an organized network of normal faults interpreted as already active during the final stages of carbonate-platform development, based on the distribution of permanently subtidal facies. From the Sinemurian onward, minor depocenters developed between structural highs controlled by conjugate faults, accompanied by widespread pelagic sedimentation during the Pliensbachian. Fault-bounded paleo-escarpments and condensed successions record the persistence of bathymetric relief into the Middle and Upper Jurassic, with progressive attenuation of these reliefs and the expansion of basinal deposits onto the paleo-escarpments. The results better support an organized extensional framework than a chaotic fault pattern mainly related to Triassic evaporite flow or halokinesis.

Geosciences doi: 10.3390/geosciences16100408

Authors: Xiaofeng Wang Fuhao Xiong Zhaoying Lü Chaoyun Yang Dongdong Yan Wei Wang Hao Wu

Positioned where the Paleo-Tethyan and Paleo-Pacific tectonic systems converge, Hainan Island preserves an important geological archive for deciphering Indosinian tectonism in the southern South China Block. However, the Indosinian magmatic–tectonic setting of Hainan Island remains highly controversial, and the nature of its mantle sources, partial-melting conditions, and temporal evolution of metasomatic agents remain insufficiently constrained. This study investigates amphibole-rich mafic rocks (hornblende gabbro) from the Zhumuling area of Danzhou, northern Hainan Island, using petrography, whole-rock geochemistry, Sr–Nd isotopes, and zircon U–Pb geochronology. Geochronological results indicate that the Zhumuling hornblende gabbro was emplaced during the Late Permian (253 ± 2 Ma). The rocks are Mg-rich (Mg# = 68–76), with gently LREE-enriched REE patterns, arc-like trace-element signatures, and weakly enriched Sr–Nd isotopic compositions [(87Sr/86Sr)i = 0.705493–0.705775; εNd(t) = −3.48 to −3.30]. Petrogenetic analysis suggests derivation by decompression melting of a subduction-modified enriched lithospheric mantle source with EMI-like isotopic affinity, followed by fractional crystallization during post-collisional extension. Combined with the regional stratigraphic, magmatic, and metamorphic records, the Zhumuling hornblende gabbro is interpreted to have formed following collision between the South China and Indochina blocks, providing new petrological constraints on the Late Permian transition from convergence to post-collisional extension in the eastern Paleo-Tethyan domain.

Geosciences doi: 10.3390/geosciences16100407

Authors: Xiaofei Lu Kai Tan Caihong Zhang Qi Li Xue Li Chengtao Li

Based on a horizontal velocity field of 1123 stations derived from the fusion of multi-source GNSS data spanning 1999–2024 (including CMONOC, densified observations, and SDCORS stations), we utilized the TDEFNODE block-dislocation model to invert for the degree of fault locking and the slip deficit distribution along the central-southern segment of the Tanlu Fault Zone. Using the PSGRN/PSCMP software, we calculated the present-day Coulomb stress field resulting from the superposition of interseismic slip accumulation and the coseismic and postseismic effects of the 1668 Tancheng earthquake. Furthermore, the VISR method was employed to obtain the strain rate field of the study area at a resolution of 0.2° × 0.2°. The results indicate that (1) the horizontal velocity field in the study area generally exhibits an ESE-oriented motion, with azimuths ranging from 104° to 110°. (2) Slip rate results indicate that the central-southern segment of the Tanlu Fault Zone is characterized by right-lateral strike-slip with extension, with right-lateral strike-slip rates ranging from 0.2 to 0.6 mm/yr and extensional rates from 0.3 to 1.7 mm/yr. (3) The slip deficit rate exhibits a distinct segmentation pattern, being stronger in the south and weaker in the north. The Jiashan–Tongcheng segment, with an average rate as high as 1.297 mm/yr, represents the zone of the most intense strain accumulation along the entire fault. Its annual seismic moment accumulation rate is approximately 3.60 × 1017 N·m/yr, corresponding to an equivalent moment magnitude of Mw ≈ 7.0 over a centennial timescale. The degree of fault locking is generally strongest in the southern segment, followed by the northern segment, and weakest in the central segment. The depth where the locking coefficient exceeds 0.90 in the Jiashan–Tongcheng segment reaches approximately 35 km under the adopted 40 km lower-boundary condition, with an average value of 0.870, which is the highest along the entire fault zone within the study area. (4) The present-day Coulomb stress field generally inherits the co- and postseismic stress transfer pattern of the 1668 Tancheng earthquake. The Weifang and Jiashan–Tongcheng segments act as zones of continuous stress loading, whereas the core source region of the Tancheng earthquake remains in a state of stress deficit. (5) The strain rate field displays a segmented pattern of “extension in the north and compression in the south,” with high maximum shear strain rates concentrated around the Weifang and Tancheng regions. (6) The Jiashan–Tongcheng segment currently features a combination of high fault locking, high slip deficit, and Coulomb stress loading, identifying it as a priority target for further seismic-hazard assessment along the central-southern segment of the Tanlu Fault Zone. Meanwhile, the high-locking and high strain rate characteristics observed near Weifang also warrant significant attention.

Geosciences doi: 10.3390/geosciences16100406

Authors: D. N. Miftakhutdinova V. V. Silantiev N. G. Olimova

Bioturbated Viséan sandstone–siltstone intervals of the South Tatar Arch have been interpreted as recording short-lived marine influence, but their ichnological basis has not been examined in detail. This study assesses the palaeoecological significance of a Zoophycos–Skolithos ichnofabric from Well 22XX80. A core specimen from 1213.5 m, approximately 2 m above eroded Tournaisian limestones and beneath a 5.5-metre-thick sandstone body, was studied on a natural split surface and in oriented cuts; the associated trace-fossil assemblage and bioturbation intensity were also recorded. Two lamellar systems are preserved. System B is assigned to Zoophycos isp., whereas System A contains structures referred to as cf. Zoophycos and cf. Teichichnus. Subvertical Skolithos burrows cross-cut System B. The lamellae of the Zoophycos spreite terminate at the burrow walls and are absent from the fill, establishing their relative order of formation. The broader assemblage, including Planolites, Teichichnus, Helminthoida and indeterminate burrows, is compatible with Palaeozoic expressions commonly assigned to the Cruziana Ichnofacies. Together with the lithological succession and regional stratigraphic context, the ichnological evidence supports marine conditions in the lower bioturbated interval. The upward transition to the overlying sandstone may reflect higher hydrodynamic energy, although greater clastic supply or migration of the depositional zone remain alternative explanations. The study illustrates the value of cross-cutting ichnofabric relationships preserved in core for recognising short-lived marine influence in siliciclastic successions.

Geosciences doi: 10.3390/geosciences16100405

Authors: Alfonso Davila Marc Neveu Wanying Kang Tori Hoehler Shannon MacKenzie Christopher R. German Terry A. Hurford Jennifer L. Eigenbrode

This review synthesizes current knowledge of Enceladus as an Ocean World, with emphasis on habitability, organic chemistry, and the search for life. We summarize data obtained by the Cassini spacecraft, including the discovery and characterization of Enceladus’ plume and subsurface ocean. We assess how plume materials constrain the composition of the ocean, while highlighting uncertainties introduced by fractionation through transport and possible ice–ocean interface processes. We further examine how ocean dynamics and plume–ocean connectivity may shape the transport and transformation of dissolved and particulate species from the moon’s interior to space. We consider possible sources of chemical energy, redox disequilibria, and abiotic organic carbon, and how they could constrain ocean biomass, biological productivity, and the detectability of potential biosignatures. Finally, we evaluate near-term exploration strategies and mission architectures for testing theories of habitability, chemical evolution, and possible life beyond Earth.

Geosciences doi: 10.3390/geosciences16100404

Authors: Botong Hu Bo Feng Chengdong Deng Xiaohong Zhang Huixing Zhu Hailong Tian

Reservoir screening for geological CO2 storage must balance hydraulic performance against geochemical reactivity, but these attributes are rarely compared under a common numerical design. We used a unified two-dimensional radial TOUGHREACT v3.32/E CO2N benchmark to compare marble, granite, and sandstone at 75 and 100 °C. Six cases shared the same geometry, brine salinity, flow functions, boundary conditions, and nominal 12.5 kg/s injection schedule. Injection lasted 10 years, followed by post-injection evolution to approximately 100 years. At 10 years, a finite-domain component balance placed 86.51–87.66% of injected CO2 in the gas phase and 12.39–13.47% in incremental aqueous CO2. Closure errors were 0.0025–0.0836%, and SmCO2 remained zero within output precision. Sandstone produced the lowest overpressure (10.7–12.0 bar), marble provided the strongest carbonate buffering, and granite showed the largest pressure and acidification penalties. A G75 rerun with half the maximum time step reproduced the 10-year metrics but reduced the approximately 100-year local porosity extreme from 18.224% to 0.171%, showing that the original long-term extreme was not time-step robust. Sensitivity tests identify injection rate as the primary control on pressure and plume extent, whereas reactive surface area mainly controls carbonate-reaction magnitude. These results show that lithology does not rank along a single performance axis: robust screening must jointly evaluate injectivity, plume footprint, phase partitioning, and post-injection reaction pathways.

Geosciences doi: 10.3390/geosciences16100403

Authors: Mohammed Cherai Mohammed Benamrane Larbi Rddad Károly Németh

The Jbel Merguechoum fluorite–barite deposit in northeastern Morocco is a granite-hosted fluorite–barite vein-type deposit whose trace and rare-earth element (REE) geochemistry, role of structural defects and trace elements in fluorite coloration, and specimen quality of the fluorite in relation to geoheritage are still poorly constrained. The site has never been drilled or mined on a commercial scale, and no reserve estimate exists. This study addresses these gaps through field and hand-specimen observations and ICP-MS analyses of green and purple fluorite samples and host Neovariscan granite. The mineralization occurs inside the granite as disseminated replacements, tension-gash fillings, geodes, and open-space vein fills, distributed along NNE-SSW to ENE-WSW normal faults. Crystal habit varies systematically with depth, and this distribution yields a range of well-preserved, museum-grade habits that are characterized here for the first time. Fluorite samples are strongly depleted in high-field-strength elements (Zr, Nb, Hf, Ta ≤ 0.33 ppm) and in thorium and uranium (Th 0.18–0.31 ppm; U 0.19–0.32 ppm), which is one to two orders of magnitude below the values measured in the granite. Among the large-ion lithophile elements, only barium is high (712–766 ppm), most probably because of barite micro-inclusions, whereas cesium (0.13–0.26 ppm) and rubidium (0.21–0.34 ppm) are very low. Total REE contents of the fluorite (17.2–19.7 ppm) are roughly one order of magnitude lower than those of the granite (189 ppm). Y/Ho ratios of 110 in the green cube’s fluorite and 135 in the purple tetrahedra fluorite are strongly superchondritic and contrast with the chondritic ratio of 28 obtained for the granite. These signatures are more consistent with precipitation from fluids that circulated through and leached the granite than from a magmatic fluid exsolved directly from it. A mass balance shows that barite micro-inclusions (≤0.13 wt%) can explain most of the Ba and Sr of the fluorite separates but have a negligible effect on the REE, Y/Ho and Eu/Eu* values. These geochemical signatures indicate precipitation from fluids that had circulated through and leached the granite, rather than from a magmatic fluid exsolved directly from it. The very low uranium and thorium contents of the purple fluorite make internal self-irradiation an unlikely dominant cause of its colour. However, they do not identify the responsible chromophore. Similarly, the presence of samarium in the green variety does not prove that samarium is the chromophore, as bulk Sm contents of the two colour types overlap. Colour models are therefore put forward as working hypotheses that still must be tested spectroscopically. Jbel Merguechoum holds particular significance for both high-level mineralogical research and collectors.

Geosciences doi: 10.3390/geosciences16100402

Authors: N. Yıldırım Gündoğdu

Groundwater ingress and moisture-related deterioration threaten railway tunnels in fractured and hydrogeologically active terrains. This study evaluates sidewall-based three-dimensional (3D) direct current resistivity (DCR) imaging for investigating potentially water-bearing conductive zones around an operational railway tunnel in Sivas, Türkiye, where crown measurements were operationally impractical. Field data were acquired along three profiles on opposing tunnel sidewalls and inverted using an unstructured tetrahedral mesh representing the tunnel cavity and acquisition geometry. The field model revealed low-resistivity zones adjacent to both sidewalls, with some features extending towards and above the crown. A field-informed synthetic reference model was used to assess survey-dependent recoverability rather than independent validation. The sidewall configuration recovered the principal conductive structures and their upward continuity, whereas longer parallel surface profiles recovered them more broadly and less distinctly. LiDAR intensity variations and field-observed wet areas provided complementary qualitative indications of surface moisture. Overall, sidewall-based 3D DCR imaging, combined with sensitivity and field-informed recoverability assessment, provides a practical strategy for operational tunnels where circumferential measurements or intrusive verification are difficult.

Geosciences doi: 10.3390/geosciences16100401

Authors: Kalehiwot Nega Manahiloh Mehdi Kadivar Victor N. Kaliakin

The lack of consensus on appropriate formulations for effective stress, the soil-water characteristic curve (SWCC), and the critical-state void ratio has plagued the constitutive modeling of unsaturated soils. This paper presents a numerical parametric investigation of the aforementioned modeling components using a rate-independent hyperelastic bounding surface plasticity model for unsaturated granular soils. The constitutive model was calibrated against experimental results for a mid-Atlantic silty sand, and stress–strain and volumetric response simulations were conducted using alternative formulations for Bishop’s effective stress parameter, SWCC, and critical-state void ratio. The study indicated that the choice of SWCC has the greatest influence on model accuracy, particularly in predicting volumetric behavior, with formulations that employ more parameters providing greater fidelity. It was observed that variations in the definition of effective stress have a comparatively limited impact, whereas accurate representations of the critical-state void ratio improve overall predictive capability. The findings are based on a single silty sand, an SWCC estimated from grain size distribution data, monotonic loading conditions, and a limited critical-state database. Accordingly, the conclusions should be interpreted within the context of the investigated material, constitutive framework, and stress range considered. The findings highlight the relative importance of key modeling components and guide the selection and calibration of constitutive models for unsaturated soils.

Geosciences doi: 10.3390/geosciences16100400

Authors: Dayou Chen Liling Zhang Pengfei Jiao Yingjian Zhang Tianmiao Ma Yanjun Ma Ruiyi Wang

To evaluate the organic geochemical characteristics, source-rock quality, and remaining hydrocarbon potential of the Lin 1–Lin 2 source rocks in the Xinglong structural belt, Hetao Basin, 20 samples from eight wells were analyzed using TOC, rock pyrolysis, chloroform-extractable bitumen “A”, kerogen microscopic components, vitrinite reflectance, GC, and GC–MS. TOC ranges from 0.11 to 3.12 wt.% (mean 1.46 wt.%), and S1 + S2 from 0.21 to 20.92 mg HC/g rock; 55% of samples are fair or better and 45% are good to excellent source rocks. Organic matter is predominantly Type II1–II2. Mean Ro values of 0.99–1.28%, together with Tmax values of 425–454 °C and PI, indicate generally mature source rocks. Maceral, n-alkane, and sterane data indicate mixed aquatic–terrestrial organic matter with a relatively greater aquatic contribution. Pr/Ph values below 1.0 in 19 of 20 samples indicate generally reducing conditions, while the gammacerane/C30 hopane ratio and its positive relationships with the C35 homohopane index and TOC support variable water-column stratification and enhanced preservation. In the regional evaporitic context, these data support episodic evaporative concentration. Overall, the source rocks are predominantly oil-prone, and some mature, organic-rich samples retain appreciable remaining pyrolysable hydrocarbon potential, supporting their significance for deep hydrocarbon exploration.

Geosciences doi: 10.3390/geosciences16100399

Authors: Larissa B. Kushakova Anastassiya P. Miroshnikova Dinara B. Kassymova Marina A. Mizernaya Ulyana V. Makarova

The growing demand for critical metals associated with the global energy transition has increased interest in their potential recovery as by-products of copper processing. This study investigates critical- and associated-element deportment in ores and flotation products from three Kazakhstan deposits representing contrasting ore-system types: the Aktogay and Bozshakol porphyry Cu–Mo deposits and the Severny Samombet Cu-skarn deposit. Bulk geochemistry, optical mineralogy, SEM–EDS observations, and technological mass-balance data were integrated to evaluate mineralogical associations and element recovery into Cu and Mo flotation products. The two porphyry systems show comparatively selective deportment: Re preferentially reports to the Mo concentrates, with recoveries of 4.05% at Aktogay and 19.03% at Bozshakol, whereas Se preferentially reports to the Cu concentrates, reaching 55.35% and 27.18%, respectively. SEM–EDS observations of Aktogay molybdenite provide mineral-scale compositional evidence for Re-bearing molybdenite. In contrast, the Severny Samombet Cu concentrate shows broader multi-element recovery, particularly for Ag (86.00%), In (74.82%), Zn (68.15%), and Cd (55.04%), accompanied by intermediate recovery of Pb, Co, and Bi. Mineralogical observations reveal a heterogeneous sulfide assemblage together with discrete Bi–Pb- and Ag–Te-bearing accessory phases. Ge shows consistently low recovery into the investigated concentrates, including only 1.31% into the Severny Samombet Cu concentrate, indicating that bulk enrichment does not necessarily translate into flotation recovery. These results demonstrate contrasting critical-element deportment patterns among the three investigated deposits and show that evaluation of potential by-products requires integration of mineralogical characteristics with quantitative flotation-product recoveries. The results provide a basis for identifying technological streams warranting further assessment for critical-metal recovery, while quantitative determination of trace-element partitioning among individual mineral hosts requires mineral-specific analytical methods.

Geosciences doi: 10.3390/geosciences16100398

Authors: Gabriel C. Frade Jefferson S. Ferreira Daniel L. Souza Tiago J. B. Sales Ellen N. S. Gomes Saulo S. Martins

Magnetic lineaments are usually delineated from derivative-based images through visually selected thresholds, a subjective procedure that is difficult to reproduce over large surveys. We present an automatic workflow based on semantic segmentation. The input attribute is built in two stages: the total gradient of the total magnetic anomaly, which, for dyke-like and contact-like sources, is independent of the magnetization direction, followed by its tilt derivative, which equalizes the response of weak and strong sources within a bounded range. This combination avoids reduction to the pole, which is unstable at the low magnetic latitudes of both surveys used here. A dual-output U-Net, predicting both a lineament mask and its skeleton, was trained on aeromagnetic data from the Carajás Province and applied without retraining to the Peixoto de Azevedo area, in the Alta Floresta Gold Province. The decision threshold was calibrated by maximizing the global Dice coefficient on the validation set, giving t∗=0.335. Applied to a synthetic model of prescribed geometry, the workflow recovered the six bodies of 20 nT or more over 84 to 100 percent of their length, including the one striking almost north–south, whose response is attenuated sevenfold at this latitude; the bodies of 12 and 7 nT were not recovered even in noise-free data, placing the detection limit between 12 and 20 nT. The median positional error is below one grid cell, and the offset normal to the trace stays under 15 m and changes sign among the bodies, so the enhancement introduces no systematic displacement. At the regional scale, the workflow produced 1886 segments dominated by east–west orientations, consistent with the regional structural framework and unchanged when the segments are weighted by their length. The workflow offers a reproducible alternative to manual lineament mapping and delivers GIS-ready structural products for regional mapping and mineral exploration.

Geosciences doi: 10.3390/geosciences16100397

Authors: Xuejiao Wang Yingchun Cui

The role of the Ross Sea continental shelf in global carbon cycling has been studied under variable ecological conditions. Here, the spatial distributions of microfossil assemblages and silica-rich spherules from surface sediments across the Ross Sea continental shelf are integrated to provide additional insights into the interaction among water masses. The spatial distribution of diatoms and benthic foraminifera reflects spatial gradients in sea-ice concentration and hydrodynamics. Silica spherules and microtektites identified in the Drygalski and Joides Troughs were classified by geochemical composition to explore potential links between characteristic elemental enrichments and water masses. Three compositional patterns of silica spherules were identified under relatively turbulent hydrodynamic conditions with silica supplied by meltwater: (1) specimens with elevated Nb and Zr distributed under consolidated sea ice conditions influenced by High-Salinity Shelf Water (HSSW); (2) Rb-enriched specimens distributed in the Drygalski and Joides Troughs with Modified Circumpolar Deep Water (MCDW) incursion; (3) ordinary specimens without specific characteristics. The microtektites characterized by high Cr are compositionally consistent with Australasian Transantarctic Mountain (AUS/TAM) types and potentially transported by HSSW circulation. More foraminiferal fragments under higher hydrodynamic conditions suggest that the water-mass interactions may contribute to carbonate preservation, in addition to water chemistry.

Geosciences doi: 10.3390/geosciences16100396

Authors: Linlin Wang Dekun Zhang Meng Wang Dagang Wang

Rapid slip along discontinuities in deep coal–rock systems releases stored energy and generates transient loading that may trigger coal bursts. This review compares intra-coal, coal–rock interface, and fault-zone slip using evidence from laboratory experiments, physical models, numerical simulations, and field observations. The comparison accounts for scale, boundary conditions, parameter calibration, and field validation. The Mohr–Coulomb criterion identifies the onset of shear failure but not the transition to unstable slip, which depends on post-peak weakening, rate dependence, contact history, and loading-system stiffness. Hazard attribution cannot rely on source energy alone. Fracture energy and frictional dissipation occur at the source, whereas only part of the radiated energy reaches a roadway after attenuation and scattering. Microseismic activity near a fault does not establish fault slip without independent evidence from a compatible source mechanism, fault displacement, or stress change. The source–path–roadway framework distinguishes source-region destressing, propagation-path modification, and roadway protection. Parameter transfer among specimen, model, and mine scales remains poorly calibrated. Most mine-scale evidence is drawn from Chinese coal mines. Prospective tests across multiple mines are needed to determine whether measurable friction and energy parameters can improve field warning and control.

Geosciences doi: 10.3390/geosciences16100395

Authors: Zakhar Ivanov Mikhail Turbakov Alsu Ivanova Mikhail Guzev Evgenii Kozhevnikov Evgenii Riabokon

Gas hydrate accumulations are often hosted in loose and weakly cemented sandy sediments, where hydrate dissociation weakens its cementing effect on the granular skeleton. Under these conditions, flow behavior may depend not only on the release of pore space but also on subsequent mechanical rearrangement of the sand matrix. The aim of this study was to evaluate the effects of external confinement and loading history on the pore space and flow response of unconsolidated quartz sand. Experiments were conducted on an extended sand-pack model enclosed in an elastic sleeve and subjected to hydraulic confinement, with distributed measurements of pressure, temperature, and electrical resistance; grain morphology was examined by scanning electron microscopy. The quartz grains exhibited pronounced angularity and heterogeneous surface microrelief. During three successive loading cycles to 190 kPa, pore volume decreased nonlinearly, and hysteresis was observed between the loading and unloading branches. The strongest spatial differences in electrical response occurred during the first cycle, whereas repeated loading reduced the differences among individual sections. Without external confinement, changes in flow regime were accompanied by marked changes in relative electrical resistance; after preliminary cyclic loading and at a confining pressure of 190 kPa, this effect was substantially weaker in most monitored sections. The results indicate that physical modeling of unconsolidated gas hydrate reservoirs should account for external pressure and the loading history of the granular medium, together with pore-space and flow characteristics. Because the two flow-test states differed simultaneously in current confinement and prior loading history, their contrast is interpreted as a combined mechanical-state effect rather than as an isolated effect of confining pressure.

Geosciences doi: 10.3390/geosciences16100394

Authors: Anna Yari Nejad Mohammad Mehdi Farahpour Bizhan Yousefi Yeganeh Michael Wagreich

The Gadvan Formation (Barremian–lower Aptian) is an important Lower Cretaceous unit in the Zagros Basin and the Persian Gulf region. In this study, a detailed microfacies analysis of the Gadvan Formation was conducted based on thin sections from core and cutting samples, as well as wireline-log data from five wells across the A, B, C, D, and E oilfields. Fourteen microfacies (MF-1 to MF-14) were identified and grouped into distinct depositional belts, including coastal-plain, inner ramp, middle ramp, and outer ramp settings. These microfacies are dominated by peloids, bioclasts, orbitolinids, benthic foraminifera, green algae, Lithocodium, and variable amounts of clay and terrigenous material, reflecting deposition within a mixed siliciclastic–carbonate ramp system. Integration of microfacies distribution with depositional models suggests that the Gadvan Formation developed on a homoclinal ramp, which locally evolved into a distally steepened geometry in the northwestern Persian Gulf. In some areas, shoal complexes separate restricted inner-ramp settings from more open-marine environments. The presence of argillaceous sandstone and scattered quartz grains in certain intervals indicates episodic influxes of siliciclastic material from adjacent continental sources. Diagenetic features have partially modified the original depositional textures. These findings contribute to the refinement of the regional depositional model of the Gadvan Formation mixed siliciclastic–carbonate ramp in the Persian Gulf.

Geosciences doi: 10.3390/geosciences16100393

Authors: Alexis Rigo Efthimios Sokos Paraskevas Paraskevopoulos

Western Greece poses significant challenges in terms of understanding its tectonic and deformation context. The Aitolo-Akarnania region of our interest is located in the eastern part of the Ionian Akarnanian Block (IAB). Its main active tectonic structures are the Katouna Stamna fault system (KSF, a left-lateral strike–slip fault that is north–south-oriented), the two east–west grabens of the Amvrakikos Gulf and Lake Trichonis, and the transition between the gulfs of Patras and Corinth. Using a new catalog with 18,710 seismic events, we determined the three-dimensional P-velocity and Vp/Vs structure of the crust by inverting P- and S-wave travel times. We explored a 3D grid with horizontal 10 km node spacing down to a depth of 40 km into 14 layers. The obtained 3D P-velocity and Vp/Vs fields clearly show the following: (1) lateral variations in seismic velocity down to a depth of 10 km, highlighting the heterogeneity of the upper crustal structure; (2) the crustal-scale KSF, which is associated with a high-Vp/Vs zone potentially influenced by fluids; (3) the graben structure of Trichonis Lake, which provides insights into its extensional tectonics through the characterization of its sedimentary fill to a depth of 10 km; and (4) a hypothetical immature decollement, dipping northwards until 25 km depth, at the transition between the gulfs of Patras and Corinth. Two seismic areas that have been observed for several decades—the eastern side of the Amvrakikos Gulf and the Pergandi Mountains—are also discussed.

Geosciences doi: 10.3390/geosciences16100392

Authors: Luis Matias Carlos Corela Afonso Loureiro Susana Gonçalves Susana Silva Hugo F. Martins Orlando Frazão Fernando Carrilho Manfred Niehus

Distributed acoustic sensing (DAS) deployed on submarine telecom cables is bound to revolutionize the earthquake monitoring routine currently performed by seismic network operators, particularly in domains where most seismic activity originates offshore. In this work, we analyze one year of DAS data recorded on a submarine telecommunication cable joining the Islands of Faial and Flores in the Azores, an area where seismic crises of volcano-tectonic origin are frequent. We explore whether spatially decimated channels can be added to the operational routine without major changes. During the DAS operation, the land network recorded 368 local and regional earthquakes. The best of these events were jointly analyzed, and earthquake parameters were compared between the original locations and those obtained by adding DAS picks. Despite the larger picking uncertainty on DAS channels, adding P and S or S-wave picks only from DAS data showed a considerable improvement in earthquake parameters, reducing the error ellipse area and the focal depth formal uncertainty. These results demonstrate that in domains where offshore seismicity is a concern and submarine telecom cables are available, integrating DAS channels into the routine operation of seismic networks considerably improves the accuracy of earthquake parameter estimation. A procedure to accomplish these results is presented.

Geosciences doi: 10.3390/geosciences16100391

Authors: Deying Wang Feilong Wang Dayong Guan Xin Zhang Hongguo Zhang Guomin Tang Gang Wang Changyu Fan

Accurate prediction of overpressure in deep reservoirs is critical for hydrocarbon ex-ploration and development. Conventional approaches, such as interpolation of sin-gle-well pressure data and seismic inversion, often produce considerable errors and uncertainty when predicting overpressure in undrilled or inter-well areas, potentially leading to misinterpretation of reservoir pressure-field distributions. To address these limitations, this study proposes a novel approach that integrates identification of overpressure origins with quantitative analysis of the geological factors controlling overpressure magnitude. Multiple regression analysis enabled accurate prediction of overpressure in undrilled areas, with relative errors of less than 5% compared with measured pressures. Based on the conventional classification of normal and overpressure systems in the Bozhong area, three pressure-system types were identified: (1) paleo-overpressure converted to present-day normal pressure, (2) paleo-normal pressure retained as present-day normal pressure, and (3) paleo-overpressure preserved as present-day overpressure. The first type, character-ized by present-day pressure coefficients of 1.0–1.1, occurs predominantly near first- and second-order faults and is attributed to vertical fault opening and subsequent pressure release. The second type occurs mainly on structural slope highs and is asso-ciated with slow sedimentation rates and the absence of high-quality source rocks. The third type, with pressure coefficients ranging from 1.2 to 2.0, is primarily distributed in slope lows and depressions. It exhibits complex origins involving individual mecha-nisms, including undercompaction, hydrocarbon generation, pressure transfer, and tectonic compression, as well as coupled mechanisms, particularly undercompaction combined with hydrocarbon generation. This complex pressure system is controlled by several geological factors, including burial depth, sedimentation rate, vitrinite reflec-tance (Ro), total organic carbon content, fault throw, fault dip angle, and distance from faults.

Geosciences doi: 10.3390/geosciences16100390

Authors: Francis J. Sousa Stephen E. Cox E. Troy Rasbury Sidney R. Hemming Kevin Hatton

The ~29.5 Ma Topernawi Formation of the northern Turkana Depression, Kenya, is among the few Oligocene syn-rift sedimentary sections exposed in the East African Rift System. We present new 40Ar/39Ar geochronology and field reconnaissance that expand both the spatial extent and paleontological potential of the Topernawi Formation. Feldspar ages from volcaniclastic sediments in the Ekitale Basin yield a weighted mean of 29.668 ± 0.054 Ma, confirming the Oligocene depositional chronology. The first geochronology from Nameriyek, a previously undated set of outcrops ~5 km west of the Ekitale Basin, demonstrates that Oligocene sedimentation may extend beyond previously known exposures. Beneath the Nameriyek ignimbrite (29.322 ± 0.092 Ma), a newly identified fine-grained lacustrine section preserves vertebrate fossils in a low-energy depositional setting with no lithologic analog in the coarse volcaniclastic facies of the Ekitale Basin. These lacustrine facies represent a new prospective in situ Oligocene site from one of the most sparsely documented intervals in the Afro-Arabian terrestrial vertebrate record. Further fieldwork is needed to test these hypotheses and explore the geology and paleontology of Nameriyek.

Geosciences doi: 10.3390/geosciences16100389

Authors: Mefe Moses Haris Haralambous Trisani Biswas

On 20 April 2026 at 07:52:58 UTC, an Mw 7.4 earthquake struck offshore Miyako, northeastern Japan. We investigated the resulting coseismic ionospheric disturbances (CIDs) using 1 Hz multi-frequency GNSS observations and ionosonde measurements. Slant total electron content derived from L1–L2, L1–L5, and L2–L5 combinations was detrended using a Savitzky–Golay filter and band-pass filtered at 2–10 min. Directional hodochrone analysis showed strong azimuthal anisotropy, with the observed perturbations propagating at apparent horizontal velocities of 0.41–1.92 km s−1 across four sectors, substantially below typical Rayleigh-wave-associated CID velocities. The observed timing and waveform characteristics are consistent with vertically excited acoustic disturbances sampled obliquely by the GNSS links. Independent ionosonde observations at Wakkanai, Icheon, and Okinawa demonstrated Multiple Cusp Signatures in the bottomside F-region within 12–17 min, with decreasing cusp sharpness toward lower latitudes. Geomagnetic and solar indices indicate relatively quiet conditions during the observations, reducing the likelihood of contamination by disturbances driven by space weather. The results enrich our understanding on coseismic ionospheric disturbances in the Mw 7–7.5 range, showing that moderate subduction earthquakes can produce direction-dependent ionospheric signatures, with apparent velocities lower than typical Rayleigh-wave-associated CID velocities, detectable through combined GNSS-TEC and ionosonde monitoring.

Geosciences doi: 10.3390/geosciences16100388

Authors: José Manuel Brandão Pedro Miguel Callapez Fernando Carlos Lopes

Between 1922 and 1926, the Geological Mission of Angola, set up by the High Commissioner Norton de Matos and based in the city of Huambo, surveyed over 30,000 km across the former Portuguese colony, while assembling large collections of fossils and rocks. Led by António Sousa Torres, an experienced naturalist at the Mineralogical Museum of the Faculty of Sciences in Lisbon, the expedition was mentored by the Swiss geologist Ernest Fleury, a renowned teacher on the engineering courses in Lisbon. For those purposes he named three of his former students to join the expedition, for each of them destinated to lead a field brigade. The knowledge generated was disseminated through international conferences and scientific publications produced in collaboration with distinguished foreign specialists. Nevertheless, the Mission’s most significant achievement was the Geological Map of Angola (1:2,000,000) published in 1933. This accomplishment not only fulfilled a political objective but also secured Portugal’s full participation in the International Geological Map of Africa, prepared in accordance with the guidelines adopted at the International Geological Congresses in Madrid (1926) and Pretoria (1929). It also established the basis of the modern geological chartography of Angola, followed by an actualised version in 1954.

Geosciences doi: 10.3390/geosciences16100387

Authors: Shengnan Sun Zuozhen Han Zhigang Song

The Shitoukoumen area in central Jilin Province, NE China, preserves a Permian blocks-in-matrix assemblage containing pre-Permian mafic and sedimentary blocks that provides an important record of the Paleozoic evolution of the eastern Paleo-Asian Ocean. We present petrographic, zircon U-Pb geochronological and Lu-Hf isotopic, and whole-rock geochemical and Sr-Nd isotopic data for newly discovered amphibolites. Zircons from the amphibolites show metamorphic characteristics, and zircon U-Pb dating yielded an age of 503 ± 4 Ma, recording Late Cambrian metamorphism. The amphibolite is tholeiitic, with low SiO2 (48.46–52.22 wt.%) and K2O (0.07–0.17 wt.%) and relatively high MgO (4.48–6.31 wt.%), Fe2O3T (11.01–15.48 wt.%), and CaO (9.07–12.55 wt.%). It has low total REE abundances and slightly LREE-depleted patterns, with no negative Nb-Ta anomalies. Its εHf(t) and εNd(t) values are +14.9 to +20.4 and +7.2 to +8.4, respectively, while the initial 87Sr/86Sr ratios are slightly elevated, consistent with seawater alteration. These geochemical and isotopic characteristics are consistent with an N-MORB-like oceanic crustal protolith derived from partial melting of a depleted spinel-facies mantle source. Together with the spatial association with the Zhangjiatun–Toudaogou–Xiaosuihe SSZ ophiolite, the amphibolite may represent a component of a metamorphic sole related to Late Cambrian intra-oceanic subduction initiation of the Paleo-Asian Ocean, although this interpretation remains tentative.

Geosciences doi: 10.3390/geosciences16100386

Authors: Bingyang Sun Xin Feng Jun Luo Zhen Zhou

Rapid regional evaluation of earthquake-induced landslide susceptibility via the traditional Newmark model is often constrained by geotechnical parameter spatial variability and subjective empirical adjustments in static factor of safety (Fs) calculations. To resolve this bottleneck, this study develops an inversion-based stability factor determination (ISFD) method for adaptive parameter configuration. Integrating sparse post-earthquake observations with multi-source geo-environmental factors, a LightGBM inversion model targets and corrects unphysical anomalies (Fs < 1.0) from traditional limit equilibrium calculations while retaining native dynamic analytical solutions for valid mechanical units (Fs ≥ 1.0), achieving a physically consistent parameter calibration within the Newmark framework. Validation in the Jiuzhaigou earthquake-affected region demonstrates that the ISFD method minimizes parameter uncertainty interferences. The model’s AUC increases from 0.727 to 0.786 (an 8.116% relative improvement), yielding high-susceptibility zones with superior spatial alignment with actual landslide inventories and mitigating localized under-predictions. Data sensitivity analysis confirms that model performance exhibits rapid initial gains followed by high-level saturation as the sample size increases, maintaining robust stability under ultra-low-sample conditions and accurately capturing critical risks along the Minjiang fault zone. The ISFD method delivers a mechanistically self-consistent, highly regionally adaptive technical workflow for rapid post-earthquake landslide susceptibility evaluation under data-scarce scenarios.

Geosciences doi: 10.3390/geosciences16090384

Authors: Hongjiao Li Hao Hu Yixue Xiong Bing Tan Yuhui Ge Aihua Xi

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.

Geosciences doi: 10.3390/geosciences16090385

Authors: Shixin Dai Jialong Xiao Bin Li Hengshun Yin

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.

Geosciences doi: 10.3390/geosciences16090383

Authors: Talifeng Biedilihan Mingming Shi Jianbang Zhao Yuxiang Zhao Yufei Su Shuaitao Yan Xiuwen Liu

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.

Geosciences doi: 10.3390/geosciences16090382

Authors: Yaxin Zhang Wanting Sun Yiyue Zhao Ailing Lei Tiezheng Li Xi Xiang Fei Zhao

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.

Geosciences doi: 10.3390/geosciences16090381

Authors: Aymon Baud Micha Horacek

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.

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.