Geosciences

19 pages, 2647 KiB

Open AccessArticle

Geological, Mineralogical, and Alteration Insights of the Intermediate-Sulfidation Epithermal Mineralization in the Sidi Aissa District, Northern Tunisia

by Jamel Ayari, Maurizio Barbieri, Tiziano Boschetti, Ahmed Sellami, Paolo Ballirano and Abdelkarim Charef

Geosciences 2025, 15(7), 269; https://doi.org/10.3390/geosciences15070269 (registering DOI) - 12 Jul 2025

Abstract

The Sidi Aissa Pb-Zn-(Ag) District, located within the Nappe Zone of northern Tunisia, has been reinterpreted as a typical intermediate-sulfidation (IS) epithermal mineralization system based on field observations and lithogeochemical analyses. Previously described as vein-style Pb-Zn deposits, the local geological framework is dominated [...] Read more.

The Sidi Aissa Pb-Zn-(Ag) District, located within the Nappe Zone of northern Tunisia, has been reinterpreted as a typical intermediate-sulfidation (IS) epithermal mineralization system based on field observations and lithogeochemical analyses. Previously described as vein-style Pb-Zn deposits, the local geological framework is dominated by extensional normal faults forming half-grabens. These faults facilitated the exhumation of deep Triassic autochthonous rocks and the extrusion of 8-Ma rhyodacites and Messinian basalts. These structures, functioning as pathways for magmatic-hydrothermal fluids, facilitated the upward migration of acidic fluids, which interacted with the surrounding wall rocks, forming a subsurface alteration zone. The mineralization, shaped by Miocene extensional tectonics and magmatic activity, occurred in three stages: early quartz-dominated veins, an intermediate barite-rich phase, and late-stage supergene oxidation. Hydrothermal alteration, characterized by silicification, argillic, and propylitic zones, is closely associated with the deposition of base metals (Pb, Zn) and silver. The mineral assemblage, including barite, galena, sphalerite, and quartz, reflects dynamic processes such as fluid boiling, mixing, and pressure changes. Full article

(This article belongs to the Section Geochemistry)

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25 pages, 6808 KiB

Open AccessArticle

Coccolithophore Assemblage Dynamics and Emiliania huxleyi Morphological Patterns During Three Sampling Campaigns Between 2017 and 2019 in the South Aegean Sea (Greece, NE Mediterranean)

by Patrick James F. Penales, Elisavet Skampa, Margarita D. Dimiza, Constantine Parinos, Dimitris Velaoras, Alexandra Pavlidou, Elisa Malinverno, Alexandra Gogou and Maria V. Triantaphyllou

Geosciences 2025, 15(7), 268; https://doi.org/10.3390/geosciences15070268 - 11 Jul 2025

Abstract

This study presents the living coccolithophore communities and the morphological variability of Emiliania huxleyi in the South Aegean Sea from three sampling regions during winter-early spring (March 2017, March 2019) and summer (August 2019). Emphasis is given to March 2017 to monitor the [...] Read more.

This study presents the living coccolithophore communities and the morphological variability of Emiliania huxleyi in the South Aegean Sea from three sampling regions during winter-early spring (March 2017, March 2019) and summer (August 2019). Emphasis is given to March 2017 to monitor the variations in coccolithophore assemblages after an exceptionally cold event in December 2016, which resulted in newly produced dense waters that ventilated the Aegean deep basins. The assemblages displayed distinct seasonality with the predominance of E. huxleyi and Syracosphaera molischii during winter-early spring, associated with the water column mixing. By contrast, summer assemblages were featured by holococcolithophores and typical taxa of warm, oligotrophic upper waters. It seems that the phytoplanktonic succession as well as the nutrient supply to the upper euphotic layers were affected by the water column perturbation during the extreme winter of 2016–2017, which led to strong convective mixing and dense water formation. The decreased coccosphere densities during March 2017, accompanied by the notable presence of diatoms, were most probably associated with a prolonged diatom bloom, causing delay in the development of the coccolithophore community and resulting in a nitrogen-limited setting. Emiliania huxleyi morphometry showed the characteristic seasonal calcification trend of the Aegean, with the dominance of smaller coccoliths in the summer and increased coccolith length and width during the cold season. The intense cold conditions and wind-induced mixing during the winter of 2016–2017 possibly increased the absorption of atmospheric CO₂ in surface waters, causing increased acidity and the subsequent presence of etched/undercalcified E. huxleyi coccoliths and other taxa, most probably implying in situ calcite dissolution. Full article

(This article belongs to the Section Biogeosciences)

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21 pages, 7866 KiB

Open AccessArticle

Asteroid and Meteorite Impacts as a Cause of Large Sedimentary Basins: A Case Study of the Transylvanian Depression

by Dumitru Ioane, Irina Stanciu and Mihaela Scradeanu

Geosciences 2025, 15(7), 267; https://doi.org/10.3390/geosciences15070267 - 9 Jul 2025

Abstract

Impact cratering determined by collisions with meteorites and asteroids is considered one of the main natural processes in the Solar System, modifying the planets and their satellites surface during time. The Earth includes in its impact record a small number of such events [...] Read more.

Impact cratering determined by collisions with meteorites and asteroids is considered one of the main natural processes in the Solar System, modifying the planets and their satellites surface during time. The Earth includes in its impact record a small number of such events due to active plate tectonics, sedimentation, and volcanism, with these geological processes destroying and burying their impact geomorphological signatures. To enlarge the Earth’s impacts database, new concepts and research methods are necessary, as well as the reinterpretation of old geological and geophysical models. Geomorphological, Geological, and Geophysical (3G) signatures in concealed impacted areas are discussed in this paper; the first offers the target characteristics, while the others give means for detecting their unseen remnants. The 3G signatures have been applied to the Transylvanian Depression, a fascinating geological structure, with difficulties in explaining the direct overlapping of regionally developed thick tuff and thick salt layers, and undecided interpretation of the regional magnetic anomaly. Large and deep sedimentary basins, such as the Precaspian, Alexandria and Transylvanian depressions, are interpreted to have started as impacted areas during the Permian or the Lower Neogene. Geophysical and geological existing information have been reinterpreted, offering a new way in understanding deeply located geological structures. Full article

(This article belongs to the Special Issue The Tectonic Origins of Sedimentary Basins: Provenance and Evolution Across Geological Time)

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26 pages, 3270 KiB

Open AccessReview

Carbon Isotopes in Magmatic Systems: Measurements, Interpretations, and the Carbon Isotopic Signature of the Earth’s Mantle

by Yves Moussallam

Geosciences 2025, 15(7), 266; https://doi.org/10.3390/geosciences15070266 - 9 Jul 2025

Abstract

Carbon isotopes in magmatic systems serve as powerful tracers for understanding magma evolution, mantle processes, the deep carbon cycle, and the origin of Earth’s carbon. This review provides a comprehensive overview of carbon isotope measurements and behavior in magmatic systems, highlighting recent technological [...] Read more.

Carbon isotopes in magmatic systems serve as powerful tracers for understanding magma evolution, mantle processes, the deep carbon cycle, and the origin of Earth’s carbon. This review provides a comprehensive overview of carbon isotope measurements and behavior in magmatic systems, highlighting recent technological advancements and scientific insights. We begin by examining methods for measuring δ¹³C in volcanic gases, vesicles, glasses, melt, and fluid inclusions. We then explore the behavior of carbon isotopes in magmatic systems, especially during magmatic degassing. Finally, we evaluate what recent advances mean for our understanding of the carbon isotope signature of the Earth’s upper mantle. Full article

(This article belongs to the Special Issue Isotope Geochemistry: Latest Developments and Applications for Geosciences)

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19 pages, 2353 KiB

Open AccessArticle

A Novel Bimodal Hydro-Mechanical Coupling Model for Evaluating Rainfall-Induced Unsaturated Slope Stability

by Tzu-Hao Huang, Ya-Sin Yang and Hsin-Fu Yeh

Geosciences 2025, 15(7), 265; https://doi.org/10.3390/geosciences15070265 - 9 Jul 2025

Abstract

The soil water characteristic curve (SWCC) is a key foundation in unsaturated soil mechanics describing the relationship between matric suction and water content, which is crucial for studies on effective stress, permeability coefficients, and other soil properties. In natural environments, colluvial and residual [...] Read more.

The soil water characteristic curve (SWCC) is a key foundation in unsaturated soil mechanics describing the relationship between matric suction and water content, which is crucial for studies on effective stress, permeability coefficients, and other soil properties. In natural environments, colluvial and residual soils typically exhibit high pore heterogeneity, and previous studies have shown that the SWCC is closely related to the distribution of pore sizes. The SWCC of soils may display either a unimodal or bimodal distribution, leading to different hydraulic behaviors. Past unsaturated slope stability analyses have used the unimodal SWCC model, but this assumption may result in evaluation errors, affecting the accuracy of seepage and slope stability analyses. This study proposes a novel bimodal hydro-mechanical coupling model to investigate the influence of bimodal SWCC representations on rainfall-induced seepage behavior and stability of unsaturated slopes. By fitting the unimodal and bimodal SWCCs with experimental data, the results show that the bimodal model provides a higher degree of fit and smaller errors, offering a more accurate description of the relationship between matric suction and effective saturation, thus improving the accuracy of soil hydraulic property assessment. Furthermore, the study established a hypothetical slope model and used field data of landslides to simulate the collapse of Babaoliao in Chiayi County, Taiwan. The results show that the bimodal model predicts slope instability 1 to 3 h earlier than the unimodal model, with the rate of change in the safety factor being about 16.6% to 25.1% higher. The research results indicate the superiority of the bimodal model in soils with dual-porosity structures. The bimodal model can improve the accuracy and reliability of slope stability assessments. Full article

(This article belongs to the Special Issue Mechanical Behavior of Critical Geo-Materials and Landslide Evolution Processes)

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25 pages, 9560 KiB

Open AccessArticle

I.S.G.E.: An Integrated Spatial Geotechnical and Geophysical Evaluation Methodology for Subsurface Investigations

by Christos Orfanos, Konstantinos Leontarakis, George Apostolopoulos, Ioannis E. Zevgolis and Bojan Brodic

Geosciences 2025, 15(7), 264; https://doi.org/10.3390/geosciences15070264 - 8 Jul 2025

Abstract

A new Integrated Spatial Geophysical and Geotechnical Evaluation (I.S.G.E) methodology has been developed to estimate the spatial distribution of geotechnical parameters using high-resolution geophysical methods. The proposed algorithm is based on fuzzy logic, and the final output is the prediction of the 2D [...] Read more.

A new Integrated Spatial Geophysical and Geotechnical Evaluation (I.S.G.E) methodology has been developed to estimate the spatial distribution of geotechnical parameters using high-resolution geophysical methods. The proposed algorithm is based on fuzzy logic, and the final output is the prediction of the 2D or 3D distribution of a geotechnical parameter within a survey area. The main advantage of the developed I.S.G.E tool is that it can propagate sparse geotechnical or point information from 1D to 2D or even 3D space through a fully automatic, unbiased statistical procedure. In this study, I.S.G.E. is implemented and evaluated first using synthetic data and, afterwards, in field condition applications. The automatically derived 3D models, depicting the spatial distribution of specific geotechnical parameters, provide engineers with an additional interpretation tool for better understanding the subsurface conditions of a survey area. Full article

(This article belongs to the Section Geophysics)

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18 pages, 5336 KiB

Open AccessArticle

Comparative Flexural Response of Mineralized Massive Sulfides and Meta-Rhyolitic Rocks

by Haitham M. Ahmed and Essam B. Moustafa

Geosciences 2025, 15(7), 263; https://doi.org/10.3390/geosciences15070263 - 8 Jul 2025

Abstract

An experimental study was conducted to investigate the flexural mechanical properties of mineralized (massive sulfides) and non-mineralized (meta-rhyolitic tuff) rock samples using a three-point bending test. Mineralogical analysis was conducted on samples from both rock categories, followed by the determination of physical properties [...] Read more.

An experimental study was conducted to investigate the flexural mechanical properties of mineralized (massive sulfides) and non-mineralized (meta-rhyolitic tuff) rock samples using a three-point bending test. Mineralogical analysis was conducted on samples from both rock categories, followed by the determination of physical properties (P-wave velocity and density). In the massive sulfide zones, there are three distinctive zones of mineralization, each exhibiting varying degrees of pyritization: the intense pyritization zone (formerly Zone A) exhibited extensive pyrite replacement of sphalerite and chalcopyrite, the transitional zone (Zone B) displays intergrowths of pyrite and sphalerite, and the coarse sulfide zone (Zone C) features coarser, less altered sulfides—polyphase hydrothermal alteration, including sericitization, silicification, and amphibole veining. Mineralized rocks showed a 35.18% increase in density (3.65 ± 0.17 kg/m³ vs. 2.72 ± 0.014 kg/m³) attributed to dense sulfide content. The flexural strength more than doubled (99.02 ± 4.42 GPa vs. 43.17 ± 6.45 GPa), experiencing a 129% increase, due to homogeneous chalcopyrite distribution and fine-grained sulfide networks. Despite strength differences, deflection rates showed a non-significant 4% variation (0.373 ± 0.083 mm for mineralized vs. 0.389 ± 0.074 mm for metamorphic rocks), indicating comparable ductility. Full article

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16 pages, 1176 KiB

Open AccessArticle

Vertebrate Skeletal Remains as Paleohydrologic Proxies: Complex Hydrologic Setting in the Upper Cretaceous Kaiparowits Formation

by Daigo Yamamura and Celina Suarez

Geosciences 2025, 15(7), 262; https://doi.org/10.3390/geosciences15070262 - 8 Jul 2025

Abstract

The Kaiparowits Formation preserves one of the best fossil records of Cretaceous North America, which provides great insight into the paleoecology. In an effort to investigate the paleohydrology of the Kaiparowits Formation, stable isotope compositions (δ¹³C, δ¹⁸O-carbonate, δ¹⁸ [...] Read more.

The Kaiparowits Formation preserves one of the best fossil records of Cretaceous North America, which provides great insight into the paleoecology. In an effort to investigate the paleohydrology of the Kaiparowits Formation, stable isotope compositions (δ¹³C, δ¹⁸O-carbonate, δ¹⁸O-phosphate) of 41 hadrosaur teeth, 27 crocodile teeth, and 35 turtle shell fragments were analyzed. The mean O-isotope compositions of drinking water (δ¹⁸O_w) calculated from the O-isotope of bioapatite (phosphate-δ¹⁸O_p) are −13.76 ± 2.08‰ (SMOW) for hadrosaur, −8.88 ± 2.76‰ (SMOW) for crocodile, and −10.14 ± 2.62‰ (SMOW) for turtle, which strongly reflect niche partitioning. The Kaiparowits formation does not fit the global trend in isotopic compositions of vertebrate skeletal remains from previous studies, which suggests a unique hydrological setting of the Kaiparowits basin. High-elevation runoff from the Mogollon Highlands and sea level fluctuation may have contributed to such a unique paleohydrology. Full article

(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)

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21 pages, 2362 KiB

Open AccessArticle

Stabilization of Expansive Clay Using Volcanic Ash

by Svetlana Melentijević, Aitor López Marcos, Roberto Ponce and Sol López-Andrés

Geosciences 2025, 15(7), 261; https://doi.org/10.3390/geosciences15070261 - 8 Jul 2025

Abstract

Considering the increasing requirements for the recovery of different natural and industrial waste materials, the application of volcanic ash as an alternative sustainable binder to traditionally employed lime and cement is proposed for soil stabilization for geotechnical engineering purposes, thus providing a reduction [...] Read more.

Considering the increasing requirements for the recovery of different natural and industrial waste materials, the application of volcanic ash as an alternative sustainable binder to traditionally employed lime and cement is proposed for soil stabilization for geotechnical engineering purposes, thus providing a reduction in carbon emissions. Soil stabilization was performed on natural clays with very high swelling potential, i.e. those classified as inadequate for reuse as a building material for geotechnical purposes. A mineralogical and chemical characterization of raw materials was carried out prior to the performance of different geotechnical laboratory tests, i.e., testing Atterberg limits, compaction, swelling potential, compressibility and resistance parameters over naturally remolded clay and soil mixtures with different binders. The swelling potential was reduced with an increase in the amount of applied binder, necessitating the addition of 10, 20, and 30% of volcanic ash compared to 3% lime, 3% cement and 5% lime, respectively, for a similar reduction in swelling potential. An investigation of the resistance parameters for soil mixture specimens that provided a suitable reduction in swelling potential for their reuse was performed, and a comparison to the parameters of naturally remolded clay was made. Full article

(This article belongs to the Section Geomechanics)

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9 pages, 1772 KiB

Open AccessArticle

Cliff-Front Dune Development During the Late Pleistocene at Sa Fortalesa (Mallorca, Western Mediterranean)

by Laura del Valle, Federica Perazzotti and Joan J. Fornós

Geosciences 2025, 15(7), 260; https://doi.org/10.3390/geosciences15070260 - 5 Jul 2025

Abstract

This study presents the first detailed analysis of a Late Pleistocene cliff-front dune in northern Mallorca (Western Mediterranean). The research is based on sedimentological fieldwork conducted in a disused coastal quarry, where stratigraphic columns were recorded and facies were described in detail. Grain [...] Read more.

This study presents the first detailed analysis of a Late Pleistocene cliff-front dune in northern Mallorca (Western Mediterranean). The research is based on sedimentological fieldwork conducted in a disused coastal quarry, where stratigraphic columns were recorded and facies were described in detail. Grain size analysis was performed using image-based measurements from representative samples, and palaeowind conditions were reconstructed through the analysis of cross-bedding orientations and empirical wind transport equations. The dune, corresponding to Unit U4, exhibits three distinct evolutionary stages: initial, intermediate, and final. During the initial stage, sediment mobilisation required wind speeds of approximately 10 m/s from the south-southwest (SSW). The intermediate stage was characterised by variable wind velocities between 5 and 8 m/s from the west-southwest (WSW). In the final stage, average wind speeds reached 7 m/s from the west (W), with intermittent peaks up to 10 m/s. These findings underscore the critical influence of wind regime and topographic constraints on aeolian sedimentation processes. By reconstructing wind dynamics and analysing sedimentary architecture, this work provides key insights into the interplay between climatic drivers and geological context in the development of coastal aeolian systems. Full article

(This article belongs to the Section Sedimentology, Stratigraphy and Palaeontology)

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26 pages, 35238 KiB

Open AccessArticle

Sediment Connectivity in Human-Impacted vs. Natural Conditions: A Case Study in a Landslide-Affected Catchment

by Mohanad Ellaithy, Davide Notti, Daniele Giordan, Marco Baldo, Jad Ghantous, Vincenzo Di Pietra, Marco Cavalli and Stefano Crema

Geosciences 2025, 15(7), 259; https://doi.org/10.3390/geosciences15070259 - 5 Jul 2025

Abstract

This research aims to characterize sediment dynamics in the Rupinaro catchment, a uniquely terraced and human-shaped basin in Italy’s Liguria region, employing geomorphometric methods to unravel sediment connectivity in a landscape vulnerable to shallow landslides. Within a scenario-based approach, we utilized high-resolution LiDAR-derived [...] Read more.

This research aims to characterize sediment dynamics in the Rupinaro catchment, a uniquely terraced and human-shaped basin in Italy’s Liguria region, employing geomorphometric methods to unravel sediment connectivity in a landscape vulnerable to shallow landslides. Within a scenario-based approach, we utilized high-resolution LiDAR-derived digital terrain models (DTMs) to calculate the Connectivity Index, comparing sediment dynamics between the original terraced landscape and a virtual natural scenario. To reconstruct a pristine slope morphology, we applied a topographic roughness-based skeletonization algorithm that simplifies terraces into linear features to simulate natural hillslope conditions and remove anthropogenic structures. The analysis was carried out considering diverse targets (e.g., hydrographic networks, road networks) and the effect of land use. The results reveal significant differences in sediment connectivity between the anthropogenic and natural morphologies, with implications for erosion and landslide susceptibility. The findings reveal that sediment connectivity is moderately higher in the scenario without terraces, indicating that terraces function as effective barriers to sediment transfer. This highlights their potential role in mitigating landslide susceptibility on steep slopes. Additionally, the results show that roads exert a stronger influence on the Connectivity Index, significantly altering flow paths. These modifications appear to contribute to increased landslide susceptibility in adjacent areas, as reflected by the higher observed landslide density within the study region. Full article

(This article belongs to the Section Natural Hazards)

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19 pages, 4273 KiB

Open AccessArticle

Improved Dynamic Correction for Seismic Data Processing: Mitigating the Stretch Effect in NMO Correction

by Pedro Cortes-Guerrero, Carlos Ortiz-Alemán, Jaime Urrutia-Fucugauchi, Sebastian Lopez-Juarez, Mauricio Gabriel Orozco-del Castillo and Mauricio Nava-Flores

Geosciences 2025, 15(7), 258; https://doi.org/10.3390/geosciences15070258 - 5 Jul 2025

Abstract

Seismic data processing is essential in hydrocarbon exploration, with normal moveout (NMO) correction being a pivotal step in enhancing seismic signal quality. However, conventional NMO correction often suffers from the stretch effect, which distorts seismic reflections and degrades data quality, especially in long-offset [...] Read more.

Seismic data processing is essential in hydrocarbon exploration, with normal moveout (NMO) correction being a pivotal step in enhancing seismic signal quality. However, conventional NMO correction often suffers from the stretch effect, which distorts seismic reflections and degrades data quality, especially in long-offset data. This study addresses the issue by analyzing synthetic models and proposing a nonhyperbolic stretch-free NMO correction technique. The proposed method significantly improves seismic data quality by preserving up to 90% of the original amplitude, maintaining frequency content stability at 30 Hz, and achieving a high reduction of stretch-related distortions. Compared to conventional NMO, our technique results in clearer seismic gathers, enhanced temporal resolution, and more accurate velocity models. These improvements have substantial implications for high-resolution subsurface imaging and precise reservoir characterization.This work offers a robust and computationally efficient solution to a longstanding limitation in seismic processing, advancing the reliability of exploration in geologically complex environments. Full article

(This article belongs to the Section Geophysics)

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22 pages, 16710 KiB

Open AccessArticle

Carbonate Seismic Facies Analysis in Reservoir Characterization: A Machine Learning Approach with Integration of Reservoir Mineralogy and Porosity

by Papa Owusu, Abdelmoneam Raef and Essam Sharaf

Geosciences 2025, 15(7), 257; https://doi.org/10.3390/geosciences15070257 - 4 Jul 2025

Abstract

Amid increasing interest in enhanced oil recovery and carbon geological sequestration programs, improved static reservoir lithofacies models are emerging as a requirement for well-guided project management. Building reservoir models can leverage seismic attribute clustering for seismic facies mapping. One challenge is that machine [...] Read more.

Amid increasing interest in enhanced oil recovery and carbon geological sequestration programs, improved static reservoir lithofacies models are emerging as a requirement for well-guided project management. Building reservoir models can leverage seismic attribute clustering for seismic facies mapping. One challenge is that machine learning (ML) seismic facies mapping is prone to a wide range of equally possible outcomes when traditional unsupervised ML classification is used. There is a need to constrain ML seismic facies outcomes to limit the predicted seismic facies to those that meet the requirements of geological plausibility for a given depositional setting. To this end, this study utilizes an unsupervised comparative hierarchical and K-means ML classification of the whole 3D seismic data spectrum and a suite of spectral bands to overcome the cluster “facies” number uncertainty in ML data partition algorithms. This comparative ML, which was leveraged with seismic resolution data preconditioning, predicted geologically plausible seismic facies, i.e., seismic facies with spatial continuity, consistent morphology across seismic bands, and two ML algorithms. Furthermore, the variation of seismic facies classes was validated against observed lithofacies at well locations for the Mississippian carbonates of Kansas. The study provides a benchmark for both unsupervised ML seismic facies clustering and an understanding of seismic facies implications for reservoir/saline-aquifer aspects in building reliable static reservoir models. Three-dimensional seismic reflection P-wave data and a suite of well logs and drilling reports constitute the data for predicting seismic facies based on seismic attribute input to hierarchical analysis and K-means clustering models. The results of seismic facies, six facies clusters, are analyzed in integration with the target-interval mineralogy and reservoir porosity. The study unravels the nature of the seismic (litho) facies interplay with porosity and sheds light on interpreting unsupervised machine learning facies in tandem with both reservoir porosity and estimated (Umaa-RHOmaa) mineralogy. Full article

(This article belongs to the Section Geophysics)

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26 pages, 9198 KiB

Open AccessArticle

The Exotic Igneous Clasts Attributed to the Cuman Cordillera: Insights into the Makeup of a Cadomian/Pan-African Basement Covered by the Moldavides of the Eastern Carpathians, Romania

by Sarolta Lőrincz, Marian Munteanu, Ştefan Marincea, Relu Dumitru Roban, Valentina Maria Cetean, George Dincă and Mihaela Melinte-Dobrinescu

Geosciences 2025, 15(7), 256; https://doi.org/10.3390/geosciences15070256 - 3 Jul 2025

Abstract

The Eastern Carpathians are thrust to the east and north over their Eastern European foreland, tectonically covering it over an area several hundred kilometers across. Information about the nature of the underthrust part of the Carpathian foreland can be obtained from the rock [...] Read more.

The Eastern Carpathians are thrust to the east and north over their Eastern European foreland, tectonically covering it over an area several hundred kilometers across. Information about the nature of the underthrust part of the Carpathian foreland can be obtained from the rock fragments preserved in the sedimentary successions of the Carpathian fold and thrust belt, specifically in the Outer Dacides and the Moldavides. Fragments of felsic rocks occurring within the sedimentary units of the Upper Cretaceous successions of the Moldavides have long been attributed to the Cuman Cordillera—an intrabasinal ridge in the Eastern Outer Carpathians. This work is the first complex geochemical and geochronological study on the exotic igneous clasts of the Cuman Cordillera. Igneous clasts from the southern part of the Moldavides (Variegated clay nappe/formation) are investigated here. They include mainly granites and rhyolites. Phaneritic rocks are composed of cumulus plagioclase, albite, amphibole and biotite, and intercumulus quartz and potassium feldspar, with apatite, magnetite, sphene, and zircon as main accessories, while the porphyritic rocks have a mineral assemblage similar to that mentioned above, displayed in a porphyritic texture with a usually crystallized groundmass. SHRIMP U-Pb zircon dating indicated the 583–597 Ma age interval for magma crystallization. Based on calcareous nannofossils, the depositional age of the investigated igneous clasts is Cenomanian to Maastrichtian, implying that the Cuman Cordillera was an emerged piece of land, herein an active source of sediments in the flysch basin for at least 40 Ma, from the Early Cretaceous (Aptian) to the Late Cretaceous (Maastrichtian). The intrusive and subvolcanic rocks show similar trends for trace and major elements, evincing their comagmatic nature. The enrichment in LILE and LREE relative to HFSE and HREE, as well as the element anomalies (e.g., negative Nb, Ta, and Eu and positive Rb, Ba, K, and Pb) suggest a convergent continental plate margin tectonic setting. Mineral chemistry suggests magma crystallization in relatively oxic conditions (magnetite series), during ascent within a depth of 15 km to 5 km. The igneous rocks attributed to the Cuman ridge display compositional and geochronological features similar to Brno and Thaya batholiths in the Brunovistulian terrane, which could be a piece of the Carpathian foreland not covered by the Tertiary thrusts. Our data confirm the non-Carpathian origin of the igneous clasts, revealing a Neoproterozoic history of the Carpathian foreland units, which include a Cadomian/Pan-African continental arc, exposed mainly during the Late Cretaceous as an intrabasinal island of the Alpine Tethys, traditionally known as the Cuman Cordillera. Full article

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30 pages, 25009 KiB

Open AccessArticle

Advancing Scalable Methods for Surface Water Monitoring: A Novel Integration of Satellite Observations and Machine Learning Techniques

by Megan Renshaw and Lori A. Magruder

Geosciences 2025, 15(7), 255; https://doi.org/10.3390/geosciences15070255 - 3 Jul 2025

Abstract

Accurate surface water volume (SWV) estimates are crucial for effective water resource management and for the regional monitoring of hydrological trends. This study introduces a multi-resolution surface water volume estimation framework that integrates ICESat-2 altimetry, Sentinel-1 Synthetic Aperture Radar (SAR), and Sentinel-2 multispectral [...] Read more.

Accurate surface water volume (SWV) estimates are crucial for effective water resource management and for the regional monitoring of hydrological trends. This study introduces a multi-resolution surface water volume estimation framework that integrates ICESat-2 altimetry, Sentinel-1 Synthetic Aperture Radar (SAR), and Sentinel-2 multispectral imagery via machine learning to improve the vertical resolution of a digital elevation model (DEM) to improve the accuracy of SWV estimates. The machine learning approach provides a significant improvement in terrain accuracy relative to the DEM, reducing RMSE by ~66% and 78% across the two models, respectively, over the initial data product fidelity. Assessing the resulting SWV estimates relative to GRACE-FO terrestrial water storage in parts of the Amazon Basin, we found strong correlations and basin-wide drying trends. Notably, the high correlation (r > 0.8) between our surface water estimates and the GRACE-FO signal in the Manaus region highlights our method’s ability to resolve key hydrological dynamics. Our results underscore the value of improved vertical DEM availability for global hydrological studies and offer a scalable framework for future applications. Future work will focus on expanding our DEM dataset, further validation, and scaling this methodology for global applications. Full article

(This article belongs to the Section Hydrogeology)

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18 pages, 13604 KiB

Open AccessEssay

Scenario Simulation of Glacier Collapse in the Amnye Machen Mountains, Qinghai–Tibetan Plateau

by Jia Li, Junhui Wu, Xuyan Ma, Dongwei Zhou, Long Li, Le Lv, Lei Guo, Lingshuai Kong and Jiahao Dian

Geosciences 2025, 15(7), 254; https://doi.org/10.3390/geosciences15070254 - 3 Jul 2025

Abstract

Simulating potential glacier collapses can provide crucial support for local disaster prevention and mitigation efforts. The Xiaomagou Glacier in the Amnye Machen Mountains, Qinghai–Tibetan Plateau, has experienced five collapses in the past two decades. Field investigation and remote sensing observations indicate that the [...] Read more.

Simulating potential glacier collapses can provide crucial support for local disaster prevention and mitigation efforts. The Xiaomagou Glacier in the Amnye Machen Mountains, Qinghai–Tibetan Plateau, has experienced five collapses in the past two decades. Field investigation and remote sensing observations indicate that the topography and bedrock characteristics of the Qushi’an No. 22 Glacier, which is 3.5 km south of the Xiaomagou Glacier, are similar to those of the Xiaomagou Glacier. More importantly, the mass movement of the Qushi’an No. 22 Glacier since 2018 closely resembles that of the Xiaomagou Glacier exhibited before its previous collapses. Therefore, in the context of rising temperatures, it is possible that the Qushi’an No. 22 Glacier will collapse in the near future. Based on remote sensing imagery and the glacier’s surface elevation changes, we reconstructed the 2004 collapse process of the Xiaomagou Glacier via numerical simulation. The key parameters of the mass flow model were optimized based on the actual deposition area of the 2004 collapse. The model with optimized parameters was then used to simulate the potential Qushi’an No. 22 Glacier collapse. Two collapse scenarios were set for the Qushi’an No. 22 Glacier. In Scenario 1, the lower half of the tongue detaches; in Scenario 2, the whole tongue detaches. Simulation results show that, in Scenario 1, the maximum mass flow depth is 72 m, the maximum mass flow speed is 51.6 m/s, and the deposition area is 5.40 × 10⁶ km²; in Scenario 2, the maximum mass flow depth is 75 m, the maximum mass flow speed is 59.7 m/s, and the deposition area is 6.32 × 10⁶ km². In both scenarios, the deposition area is much larger than that of the Xiaomagou Glacier 2004 collapse, which had a deposition area of 2.21 × 10⁶ km². The simulation results suggest that the Qushi’an No. 22 Glacier collapse could devastate the pastures and township roads lying in front of the glacier, seriously affecting local transportation and livestock farming; furthermore, it may deposit in the Qinglong River, forming a large, dammed lake. At present, the Qushi’an No. 22 Glacier remains in an unstable state. It is crucial to strengthen monitoring of its surface morphology, flow speed, and elevation. Full article

(This article belongs to the Section Cryosphere)

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25 pages, 7171 KiB

Open AccessArticle

CFD–DEM Analysis of Internal Soil Erosion Induced by Infiltration into Defective Buried Pipes

by Jun Xu, Fei Wang and Bryce Vaughan

Geosciences 2025, 15(7), 253; https://doi.org/10.3390/geosciences15070253 - 3 Jul 2025

Abstract

Internal soil erosion caused by water infiltration around defective buried pipes poses a significant threat to the long-term stability of underground infrastructures such as pipelines and highway culverts. This study employs a coupled computational fluid dynamics–discrete element method (CFD–DEM) framework to simulate the [...] Read more.

Internal soil erosion caused by water infiltration around defective buried pipes poses a significant threat to the long-term stability of underground infrastructures such as pipelines and highway culverts. This study employs a coupled computational fluid dynamics–discrete element method (CFD–DEM) framework to simulate the detachment, transport, and redistribution of soil particles under varying infiltration pressures and pipe defect geometries. Using ANSYS Fluent (CFD) and Rocky (DEM), the simulation resolves both the fluid flow field and granular particle dynamics, capturing erosion cavity formation, void evolution, and soil particle transport in three dimensions. The results reveal that increased infiltration pressure and defect size in the buried pipe significantly accelerate the process of erosion and sinkhole formation, leading to potentially unstable subsurface conditions. Visualization of particle migration, sinkhole development, and soil velocity distributions provides insight into the mechanisms driving localized failure. The findings highlight the importance of considering fluid–particle interactions and defect characteristics in the design and maintenance of buried structures, offering a predictive basis for assessing erosion risk and infrastructure vulnerability. Full article

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39 pages, 15659 KiB

Open AccessArticle

Examples of Rupture Patterns of the 2023, Mw 7.8 Kahramanmaraş Surface-Faulting Earthquake, Türkiye

by Stefano Pucci, Marco Caciagli, Raffaele Azzaro, Pio Di Manna, Anna Maria Blumetti, Valerio Poggi, Paolo Marco De Martini, Riccardo Civico, Rosa Nappi, Elif Ünsal and Orhan Tatar

Geosciences 2025, 15(7), 252; https://doi.org/10.3390/geosciences15070252 - 2 Jul 2025

Abstract

Field surveys focused on detailed mapping and measurements of coseismic surface ruptures along the causative fault of the 6 February 2023, Mw 7.8 Kahramanmaraş earthquake. The aim was filling gaps in the previously available surface-faulting trace, validating the accuracy of data obtained from [...] Read more.

Field surveys focused on detailed mapping and measurements of coseismic surface ruptures along the causative fault of the 6 February 2023, Mw 7.8 Kahramanmaraş earthquake. The aim was filling gaps in the previously available surface-faulting trace, validating the accuracy of data obtained from remote sensing, refining fault offset estimates, and gaining a deeper understanding of both the local and overall patterns of the main rupture strands. Measurements and observations confirm dominating sinistral strike-slip movement. An integrated and comprehensive slip distribution curve shows peaks reaching over 700 cm, highlighting the near-fault expressing up to 70% of the deep net offset. In general, the slip distribution curve shows a strong correlation with the larger north-eastern deformation of the geodetic far field dislocation field and major deep slip patches. The overall rupture trace is generally straight and narrow with significant geometric complexities at a local scale. This results in transtensional and transpressional secondary structures, as multi-strand positive and negative tectonic flowers, hosting different patterns of the mole-tracks at the outcrop scale. The comprehensive and detailed field survey allowed characterizing the structural framework and geometric complexity of the surface faulting, ensuring accurate offset measurements and the reliable interpretation of both morphological and geometric features. Full article

(This article belongs to the Topic Geomorphological Processes of Continental Landscapes in Tectonically Active Areas)

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15 pages, 2295 KiB

Open AccessArticle

A Deep Learning Approach for Spatiotemporal Feature Classification of Infrasound Signals

by Xiaofeng Tan, Xihai Li, Hongru Li, Xiaoniu Zeng, Shengjie Luo and Tianyou Liu

Geosciences 2025, 15(7), 251; https://doi.org/10.3390/geosciences15070251 - 2 Jul 2025

Abstract

Infrasound signal classification remains a critical challenge in geophysical monitoring systems, where classification performance is fundamentally constrained by feature extraction efficacy. Existing two-dimensional feature extraction methods suffer from inadequate representation of spatiotemporal signal dynamics, leading to performance degradation in long-distance detection scenarios. To [...] Read more.

Infrasound signal classification remains a critical challenge in geophysical monitoring systems, where classification performance is fundamentally constrained by feature extraction efficacy. Existing two-dimensional feature extraction methods suffer from inadequate representation of spatiotemporal signal dynamics, leading to performance degradation in long-distance detection scenarios. To overcome these limitations, we present a novel classification framework that effectively captures spatiotemporal infrasound characteristics through Gramian Angular Field (GAF) transformation. The proposed method introduces an innovative encoding scheme that transforms one-dimensional infrasonic waveforms into two-dimensional GAF images while preserving crucial temporal dependencies. Building upon this representation, we develop an advanced hybrid deep learning architecture that integrates ConvLSTM networks to simultaneously extract and correlate spatial and spectral features. Extensive experimental validation on both chemical explosion and seismic infrasound datasets shows our approach achieves 92.4% classification accuracy, demonstrating consistent superiority over four state-of-the-art benchmark methods. These findings demonstrate the effectiveness of the proposed method. Full article

(This article belongs to the Section Geophysics)

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