Geosciences

34 pages, 3695 KB

Open AccessEditor’s ChoiceReview

Updated Synthesis of the Upper Cretaceous Vertebrate Assemblages from the Northern Onshore Sector of the Portuguese West Iberian Margin

by Ricardo Jorge Pimentel, Fernando Barroso-Barcenilla, Mélani Berrocal-Casero and Pedro Miguel Callapez

Geosciences 2025, 15(12), 477; https://doi.org/10.3390/geosciences15120477 - 18 Dec 2025

Viewed by 1364

Abstract

Vertebrate remains from the Upper Cretaceous of Portugal have been studied for more than 140 years, beginning with the pioneering work of the Geological Commissions and early vertebrate specialists. The Cenomanian of Portugal occupies a key position in understanding vertebrate assemblages from the [...] Read more.

Vertebrate remains from the Upper Cretaceous of Portugal have been studied for more than 140 years, beginning with the pioneering work of the Geological Commissions and early vertebrate specialists. The Cenomanian of Portugal occupies a key position in understanding vertebrate assemblages from the south-western European Late Cretaceous archipelago. Recent discoveries in the Cenomanian of the onshore northern sector of the Portuguese West Iberian Margin have revealed two new genera of Squamata and Crocodylomorpha, as well as extended biogeographical ranges for groups such as Obaichthyidae. Although Campanian–Maastrichtian fossils are limited to the northern sector, they provide valuable insights into the composition and evolution of western Iberian vertebrate faunas, including significant remains of small dinosaurs and mammals, and the westernmost European occurrences of Pycnodontiformes, Holostei, Elopiformes, Amphibia, Testudines, Squamata, and Crocodylomorpha. The Upper Cretaceous of the Portuguese onshore northern sector of the West Iberian Margin has yielded six vertebrate holotypes, four lectotypes, and syntypes though much material remains undescribed or in need of revision. Identifying additional fossil sites is essential to further expand the dataset. This contribution integrates historical and current knowledge and highlights key priorities for future research. Full article

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

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29 pages, 13958 KB

Open AccessArticle

Identification of Aquifer Systems in Weathered and Fractured Sandstone Based on 3D Geological Modeling in the Mesa de Los Santos (Santander, Colombia)

by Maria Cetina, Francisco Velandia, Sully Gómez, Nicolas Patris, Andrés Sánchez, Edward Duarte, Mauricio Carrillo-Hernández, Johel Silva and Jean-Denis Taupin

Geosciences 2025, 15(12), 476; https://doi.org/10.3390/geosciences15120476 - 17 Dec 2025

Viewed by 589

Abstract

Mesa de Los Santos is an elevated plateau of the Eastern Cordillera of Colombia bordered by escarpments, where groundwater resources are limited to the local recharge. The geological unit with the greatest hydrogeological potential is Los Santos Formation (Lower Cretaceous), which presents three [...] Read more.

Mesa de Los Santos is an elevated plateau of the Eastern Cordillera of Colombia bordered by escarpments, where groundwater resources are limited to the local recharge. The geological unit with the greatest hydrogeological potential is Los Santos Formation (Lower Cretaceous), which presents three members (Lower, Medium and Upper). Based on stratigraphic information and hydrogeological information, three aquifer systems were characterized in the Upper Member: The Shallow Aquifer System (SAS), the Upper Aquifer 1 (UA1), and Upper Aquifer 2 (UA2). The SAS comprises discontinuous aquifers with groundwater flowing very close to the surface, circulating through weathered and fractured levels. UA1 and UA2 contain groundwater flowing through fractures. Groundwater in UA1 circulates through the top of the Upper Member, is underlain by a predominantly muddy base and exhibits an E-W and NE-SW flow consistent with the dip of the layers and the main directions of fractures. UA2 groundwater flows through the base of the Upper Member and is limited by the impermeable Middle Member. Stable water isotopes (δ¹⁸O, δ²H) data show three behaviors: (i) large temporal variability indicating a rapid flow through fractures in the three aquifers, and through primary porosity mainly due to weathering in the SAS; (ii) slower flows, with low temporal variability, showing well-mixed water of meteoric origin in the SAS, UA1, and UA2; (iii) groundwater with signs of evaporation indicating the connection between wetlands and the SAS in some cases. Full article

(This article belongs to the Special Issue Advanced Studies in Hydrogeology: Making the Invisible Visible)

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19 pages, 9554 KB

Open AccessArticle

Characterization of Microbialites Using ERT and GPR: Insights from Neoproterozoic and Mesozoic Carbonate Systems

by Aritz Urruela, Albert Casas-Ponsatí, Francisco Pinheiro Lima-Filho, Mahjoub Himi and Lluís Rivero

Geosciences 2025, 15(12), 475; https://doi.org/10.3390/geosciences15120475 - 17 Dec 2025

Viewed by 306

Abstract

The detection of subsurface stromatolites remains challenging due to their complex morphology and heterogeneous composition. This study assesses the combined application of Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) for identifying microbialites in two contrasting geological and climatic settings: the Neoproterozoic [...] Read more.

The detection of subsurface stromatolites remains challenging due to their complex morphology and heterogeneous composition. This study assesses the combined application of Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) for identifying microbialites in two contrasting geological and climatic settings: the Neoproterozoic Salitre Formation in Brazil and the Mesozoic microbialite-bearing limestones in northern Spain. High-resolution ERT profiles processed with raster-based blob detection algorithms revealed subcircular high-resistivity anomalies consistent with the studied microbialite morphologies, with strong resistivity contrasts observed between microbialites and host matrices despite variations in absolute values linked to lithology and soil moisture. In parallel, GPR surveys analyzed with a peak detection algorithm delineated domal reflectors and clusters of high-amplitude reflections that directly captured the internal architecture of stromatolitic buildups. With decimetric vertical resolution, GPR offered unrivaled insights into internal morphology, complementing the broader-scale imaging capacity of ERT. The complementary strengths of both methods are clear: ERT excels at mapping distribution and stratigraphic context, while GPR provides unparalleled resolution of internal structures. Crucially, this work advances previous efforts by explicitly demonstrating that integrated ERT-GPR approaches, when combined with algorithm-based interpretation, can resolve microbialite morphology, distribution and internal architecture with a level of objectivity not previously achieved. Beyond methodological refinement, these findings open new avenues for reconstructing microbialite development and preservation in ancient carbonate systems and hold strong potential for application in other geological contexts where complex carbonate structures challenge traditional geophysical imaging. Full article

(This article belongs to the Section Geophysics)

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6 pages, 177 KB

Open AccessEditorial

Precursory Phenomena Prior to Earthquakes

by Dimitrios Nikolopoulos

Geosciences 2025, 15(12), 474; https://doi.org/10.3390/geosciences15120474 - 15 Dec 2025

Viewed by 529

Abstract

This editorial is a part of the Special Issue (SI) “Precursory Phenomena Prior to Earthquakes (2nd Edition)” [...] Full article

(This article belongs to the Special Issue Precursory Phenomena Prior to Earthquakes (2nd Edition))

35 pages, 14689 KB

Open AccessArticle

Multivariate Statistical Analysis and S-A Multifractal Modeling of Lithogeochemical Data for Mineral Exploration: A Case Study from the Buerhantu Area, Hadamengou Gold Orefield, Inner Mongolia, China

by Songhao Fan, Da Wang, Biao Yang, Huchao Ma, Rilige Su, Lei Chen, Panyun Su, Xiuhong Hou, Hanqin Lv and Zhiwei Xia

Geosciences 2025, 15(12), 473; https://doi.org/10.3390/geosciences15120473 - 15 Dec 2025

Viewed by 406

Abstract

The Hadamengou gold deposit, located on the northern margin of the North China Craton, represents one of the region‘s most significant gold mineralization clusters. However, exploration in its deeper and peripheral sectors is constrained by ecological protection policies and the structural complexity of [...] Read more.

The Hadamengou gold deposit, located on the northern margin of the North China Craton, represents one of the region‘s most significant gold mineralization clusters. However, exploration in its deeper and peripheral sectors is constrained by ecological protection policies and the structural complexity of the ore-forming systems. Multivariate analysis combined with multi-model integration provides an effective mathematical approach for interpretating geochemical datasets and guiding mineral exploration, yet, its application in the Hadamengou region has not been systematically investigated. To address this research gap, this study developed a pilot framework in the key Buerhantu area, on the periphery of the Hadamengou metallogenic cluster, applying and adapting a multivariate-multimodel methodology for mineral prediction. The goal is to improve exploration targeting, particularly for concealed and deep-seated mineralization, while addressing the methodological challenges of mathematical modeling in complex geological conditions. Using 1:10,000-scale lithogeochemical data, we implemented a three-step workflow. First, isometric log-ratio (ILR) and centered log-ratio (CLR) transformations were compared to optimize data preprocessing, with a reference column (YD) added to overcome ILR constraints. Second, principal component analysis (PCA) identified a metallogenic element association (Sb-As-Sn-Au-Ag-Cu-Pb-Mo-W-Bi) consistent with district-scale mineralization patterns. Third, S-A multifractal modeling of factor scores (F1–F4) effectively separated noise, background, and anomalies, producing refined geochemical maps. Compared with conventional inverse distance weighting (IDW), the S-A model enhanced anomaly delineation and exploration targeting. Five anomalous zones (AP01–AP05) were identified. Drilling at AP01 confirmed the presence of deep gold mineralization, and the remaining anomalies are recommended for surface verification. This study demonstrates the utility of S-A multifractal modeling for geochemical anomaly detection and its effectiveness in defining exploration targets and improving exploration efficiency in underexplored areas of the Hadamengou district. Full article

(This article belongs to the Section Geochemistry)

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14 pages, 3569 KB

Open AccessArticle

Persistence of Soil Water Repellency After the 2022 Bolt Creek Fire

by Mustafa Demir, Peter R. Robichaud and Idil Deniz Akin

Geosciences 2025, 15(12), 472; https://doi.org/10.3390/geosciences15120472 - 15 Dec 2025

Viewed by 347

Abstract

Wildfire ash and water-repellent soil are new materials that are formed after a wildfire that change the mechanical and hydraulic behavior of wildfire-burned slopes. Wildfire ash is known to be typically hydrophilic and to retain water, whereas the water-repellent soil layer acts as [...] Read more.

Wildfire ash and water-repellent soil are new materials that are formed after a wildfire that change the mechanical and hydraulic behavior of wildfire-burned slopes. Wildfire ash is known to be typically hydrophilic and to retain water, whereas the water-repellent soil layer acts as a hydraulic barrier. However, there is limited in situ soil water content data to understand the short- and long-term impacts of wildfire ash and a water-repellent soil layer on the hydromechanical behavior of burned slopes. This study investigates the trends in water content of wildfire ash, water-repellent soil, and subsurface soil after the 2022 Bolt Creek Wildfire near Skykomish, WA. The ash deposit averaged 10 cm, with a maximum 30 cm thickness in channels immediately after the fire, which allowed the in situ measurement of ash water content. Soil water content sensors were installed in the ash and subsurface soil layers, and changes in the water content were monitored for a year after the fire. The surface ash layer was above a thin (<1 cm) water-repellent soil layer, which was followed by the soil that did not show any apparent effects from the fire. The results showed a reduction in ash thickness and the persistence of the water-repellent layer over a year. Full article

(This article belongs to the Special Issue Advances in Thermo-Hydro-Mechanical and Biochemical (THMBC) Characterization and Modelling of Unsaturated Soils)

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19 pages, 7430 KB

Open AccessEditor’s ChoiceArticle

The Hole in the Pacific LLVP and Multipathed SKS

by Daoyuan Sun

Geosciences 2025, 15(12), 471; https://doi.org/10.3390/geosciences15120471 - 13 Dec 2025

Viewed by 552

Abstract

In contrast to a relatively simple whole structure of the African Large Low Velocity Province (LLVP), the Mid-Pacific LLVP appears to be much more complex and likely interacts more with the down-going slab debris from the circum-Pacific subduction zones. Tomographic models show an [...] Read more.

In contrast to a relatively simple whole structure of the African Large Low Velocity Province (LLVP), the Mid-Pacific LLVP appears to be much more complex and likely interacts more with the down-going slab debris from the circum-Pacific subduction zones. Tomographic models show an apparent hole in the Mid-Pacific LLVP, coinciding with observed anomalous SPdKS arrivals. Previous studies have linked these anomalies to a large-scale mega ultra-low velocity zone (ULVZ) exhibiting up to a 45% S-wave velocity reduction. To further investigate this anomaly, we analyzed SKS waveforms from Fiji–Tonga earthquakes recorded by the USArray. Many events display pronounced travel time jumps and waveform distortions near epicentral distances of 100°, consistent with strong multipathing effects. Notably, such complexities are absent in S and SKKS phases, indicating that only the down-going SKS leg is affected. Using waveform modeling, we find that a northeast-dipping high-velocity anomaly approximately 300 km wide, 800 km long, and with a shear velocity increase of ~2% provides a good fit to the observed SKS data. This apparent LLVP hole may represent a localized downwelling within the LLVP or a remnant slab fragment interacting with the deep mantle. Full article

(This article belongs to the Special Issue Seismology of the Dynamic Deep Earth)

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30 pages, 10644 KB

Open AccessArticle

Integrating PCA and Fractal Modeling for Identifying Geochemical Anomalies in the Tropics: The Malang–Lumajang Volcanic Arc, Indonesia

by Wahyu Widodo, Ernowo Ernowo, Ridho Nanda Pratama, Mochamad Rifat Noor, Denni Widhiyatna, Edya Putra, Arifudin Idrus, Bambang Pardiarto, Zach Boakes, Martua Raja Parningotan, Triswan Suseno, Retno Damayanti, Purnama Sendjaja, Dwi Rachmawati and Ayumi Hana Putri Ramadani

Geosciences 2025, 15(12), 470; https://doi.org/10.3390/geosciences15120470 - 12 Dec 2025

Cited by 1 | Viewed by 678

Abstract

Intense chemical weathering in tropical environments poses challenges for conventional geochemical exploration, as primary lithological signatures become heavily altered. Stream sediment geochemistry provides a robust alternative for detecting anomalous geochemical patterns under these conditions. In this study, 636 stream sediment samples and 15 [...] Read more.

Intense chemical weathering in tropical environments poses challenges for conventional geochemical exploration, as primary lithological signatures become heavily altered. Stream sediment geochemistry provides a robust alternative for detecting anomalous geochemical patterns under these conditions. In this study, 636 stream sediment samples and 15 rock samples were evaluated using Principal Component Analysis (PCA), Median + 2 Median Absolute Deviation (MAD), and Concentration–Area (C–A) fractal modeling to identify potential anomaly zones. These results were compared with the traditional Mean plus 2 Standard Deviation (SD) approach. The findings indicated that Mean + 2SD offers a conservative threshold but overlooks anomalies in heterogeneous datasets, while Median + 2MAD provides robustness against outliers. The C-A fractal model effectively characterizes low- and high-order anomalies by capturing multiscale variability. Elements such as Au–Ag–Hg–Se–Sb–As form a system indicating low- to intermediate-sulphated epithermal mineralization. Au–Pb points to polymetallic hydrothermal mineralization along intrusive contacts. The southern region is a primary mineralization center controlled by an intrusive–volcanic boundary, whereas the east and west areas exhibit secondary mineralization, characterized by altered lava breccia. The correlation between shallow epithermal and deeper intrusive-related porphyry systems, especially regarding Au–Ag, offers new insights into the metallogenic landscape of the Sunda–Banda arc. Beyond regional significance, this research presents a geostatistical workflow designed to mitigate exploration uncertainty in geochemically complex zones, providing a structured approach applicable to volcanic-arc mineralized provinces worldwide. Full article

(This article belongs to the Section Geochemistry)

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24 pages, 5771 KB

Open AccessArticle

Analyzing the Connectivity of Fracture Networks Using Natural Fracture Characteristics in the Khairi Murat Range, Potwar Region, Northern Pakistan

by Nasrullah Dasti and Mian Sohail Akram

Geosciences 2025, 15(12), 469; https://doi.org/10.3390/geosciences15120469 - 11 Dec 2025

Viewed by 550

Abstract

Rock fracture connectivity is a developing concept that demonstrates the effectiveness of fracture networks in facilitating the preferential flow of fluid through the medium. This study demonstrates the significance and impact of fracture parameters in determining the connectivity of fracture networks. An attempt [...] Read more.

Rock fracture connectivity is a developing concept that demonstrates the effectiveness of fracture networks in facilitating the preferential flow of fluid through the medium. This study demonstrates the significance and impact of fracture parameters in determining the connectivity of fracture networks. An attempt is made to define fracture parameters, such as fracture density, length, and the quotient of dispersion in their orientation, in addition to understanding the characteristics of fracture and the connectivity of the fracture network in a specified domain. The results based on field observations and measurements at outcrops of the Khairi Murat Range, including the study of field photographs and images, indicate that the fractional connected area (FCA) significantly determines the connectivity of fracture networks and, conversely, depends upon the fracture parameters. Eight fracture sets identified in the study area represent the intensity of dispersion of the strike angles of the fractures. The angular dispersion, i.e., the Fisher coefficient of strike angle of the fracture sets, ranges from 0.26 to 1, indicating that the fracture sets are systematic and concentrated in one direction. Although fracture density and length establish a linear relationship, fracture network connectivity is surprisingly independent of length. Scale-dependent fracture length plays a significant role in serving as the “backbone” of the network in the connectivity of the fracture system. Instead of the length and size of the cluster, fracture network connectivity is affected by fracture orientation and density. Characterization of the fracture properties-based approach successfully explores the connectivity of fracture networks on an outcrop scale. Full article

(This article belongs to the Topic Advances in Groundwater Science and Engineering)

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26 pages, 10994 KB

Open AccessArticle

Mass Movement Risk Assessment in the Loess Hilly Region of Northwest China Using a Weighted Information Theoretic Framework

by Zhiyong Hu, Jinkai Yan, Yongfeng Gong, Fangyuan Jiang, Guorui Wang, Hui Wang, Xiaofeng He, Shichang Gao and Zheng He

Geosciences 2025, 15(12), 468; https://doi.org/10.3390/geosciences15120468 - 10 Dec 2025

Viewed by 420

Abstract

Ground instability represents a major environmental hazard in the Loess Hilly region of Northwest China, threatening infrastructure and human safety. This study establishes an integrated information-theoretic framework for evaluating regional instability risk by coupling the information value model with analytic hierarchy process (AHP) [...] Read more.

Ground instability represents a major environmental hazard in the Loess Hilly region of Northwest China, threatening infrastructure and human safety. This study establishes an integrated information-theoretic framework for evaluating regional instability risk by coupling the information value model with analytic hierarchy process (AHP) weighting and subsequent hazard–exposure synthesis. Seven conditioning factors—geomorphic type, slope, aspect, lithology, distance to faults, river system, and NDVI—were analyzed to derive susceptibility, while rainfall, peak ground acceleration, and human engineering activity were incorporated as triggering elements of hazard. Exposure was quantified from population density and infrastructure exposure, and overall risk was defined as the product of hazard and exposure after normalization and calibration. Results indicate that hilly landforms, slopes of 10–20°, and NDVI values between 0.3 and 0.6 are the dominant controls on instability occurrence. Extreme-risk zones are concentrated in central Guyuan and northwest Shizuishan (0.16% of the study area), with high-risk zones covering 21.87%, moderate-risk zones covering 41.65%, and low-risk zones covering 6.32%. Model validation yields an AUC of 0.833 and a consistent increase in observed disaster-point density from low to extreme classes, confirming strong predictive reliability. These results demonstrate that the proposed calibrated framework provides a practical and transferable tool for ground-instability risk assessment and land-use planning in loess terrains. Full article

(This article belongs to the Topic Remote Sensing and Geological Disasters)

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17 pages, 1815 KB

Open AccessArticle

Assessing Climate and Watershed Controls on Rain-on-Snow Runoff Using XGBoost-SHAP Explainable AI (XAI)

by Yog Aryal

Geosciences 2025, 15(12), 467; https://doi.org/10.3390/geosciences15120467 - 9 Dec 2025

Viewed by 555

Abstract

Rain-on-snow (ROS) events significantly impact hydrological processes in snowy regions, yet their seasonal drivers remain poorly understood, particularly in low-elevation and low-gradient catchments. This study uses an XGBoost-SHAP explainable artificial intelligence (XAI) model to analyze meteorological and watershed controls on ROS runoff in [...] Read more.

Rain-on-snow (ROS) events significantly impact hydrological processes in snowy regions, yet their seasonal drivers remain poorly understood, particularly in low-elevation and low-gradient catchments. This study uses an XGBoost-SHAP explainable artificial intelligence (XAI) model to analyze meteorological and watershed controls on ROS runoff in the Laurentian Great Lakes region. We used daily discharge, precipitation, temperature, and snow depth data from 2000 to 2023, available from HYSETS, to identify ROS runoff. The XGBoost model’s performance for predicting ROS runoff was higher in winter (R² = 0.65, Nash–Sutcliffe = 0.59) than in spring (R² = 0.56, Nash–Sutcliffe = 0.49), indicating greater predictability in colder months. The results reveal that rainfall and temperature dominated ROS runoff generation, jointly explaining more than 60% of total model importance, while snow depth accounted for 8–12% depending on season. Winter runoff is predominantly governed by climatic factors—rainfall, air temperature, and their interactions—with soil permeability and slope orientation playing secondary roles. In contrast, spring runoff shows increased sensitivity to land cover characteristics, particularly agricultural and shrub cover, as vegetation-driven processes become more influential. Snow depth effects shift from predominantly negative in winter, where snow acts as storage, to positive contributions in spring at shallow to moderate depths. ROS runoff responded positively to air temperatures exceeding approximately 2.5 °C in both winter and spring. Land cover influences on ROS runoff differ by vegetation type and season. Agricultural areas consistently increase runoff in both seasons, likely due to limited infiltration, whereas shrub-dominated regions exhibit stronger runoff enhancement in spring. The seasonal shift in dominant controls underscores the importance of accounting for land–climate interactions in predicting ROS runoff under future climate scenarios. These insights are essential for improving flood forecasting, managing water resources, and developing adaptive strategies. Full article

(This article belongs to the Section Cryosphere)

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22 pages, 9957 KB

Open AccessArticle

Analysis of Cenozoic Structural Evolution and Basin Formation Models in the Nanpu Sag, Bohai Bay Basin, China

by Liangli Xiong, Han Yu, Junjie Xu, Rongwei Zhu, Zhangshu Lei and Wenbo Du

Geosciences 2025, 15(12), 466; https://doi.org/10.3390/geosciences15120466 - 8 Dec 2025

Viewed by 412

Abstract

Based on comprehensive interpretation of three-dimensional seismic data and quantitative analysis of basin-boundary fault activity in the Nanpu Sag, this study employs subsidence history backstripping and equilibrium profile techniques to reconstruct the structural evolution of the main profile. The results indicate that the [...] Read more.

Based on comprehensive interpretation of three-dimensional seismic data and quantitative analysis of basin-boundary fault activity in the Nanpu Sag, this study employs subsidence history backstripping and equilibrium profile techniques to reconstruct the structural evolution of the main profile. The results indicate that the Cenozoic evolution of the Nanpu Sag can be divided into a syn-rift stage and a post-rift stage, with the syn-rift stage further subdivided into Rift I and Rift II episodes. During Rift I, tectonic activity was primarily controlled by the NE- and NEE-trending Xinanzhuang Fault, Shabei Fault, and No. 2 Fault Zone, which formed under a NW–SE extensional stress regime and governed the development of NE- or NEE-trending faults and associated sedimentary subsidence centers. In Rift II, tectonic activity was dominated by a southward-curved normal fault system, composed of the Xinanzhuang, Gaoliu, and Baigezhuang faults, as well as the Shabei Fault, reflecting the influence of a near N–S ex-tensional stress field. The progressive southward migration of the Sag’s subsidence center over time—from the Linque sub-sag in the third section of the Shahe Formation to the Caofeidian sub-sag in the Dongying Formation—and noting, coupled with the pronounced left-lateral strike-slip characteristics of the Baigezhuang Fault and No. 4 Fault, and regional tectonic evolution analysis of the Bohai Bay Basin, support the proposal that a strike-slip extension mechanism—characterized by lateral strike-slip and forward extension—constitutes the fundamental developmental model of the Nanpu Sag. This study deepens the understanding of the tectonic evolution of the Nanpu Sag and provides new insights in-to the dynamic mechanisms governing the formation of similar Sags in the Bohai Bay Basin. Full article

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16 pages, 7823 KB

Open AccessArticle

Historical Geomagnetic Declination in Mainland Spain Derived from Topographic Fieldwork Records (1871–1940)

by Jose Manuel Tordesillas, Francisco Javier Pavón-Carrasco, Alberto Núñez, Marina López-Muga, Elena Camacho and Ana Belén Anquela

Geosciences 2025, 15(12), 465; https://doi.org/10.3390/geosciences15120465 - 6 Dec 2025

Viewed by 619

Abstract

In 1870, the newly created Instituto Geográfico of Spain, the precursor of the current Instituto Geográfico Nacional (IGN), began to carry out work for the preparation of the National Topographic Map of Spain, a major project that would take almost 100 years to [...] Read more.

In 1870, the newly created Instituto Geográfico of Spain, the precursor of the current Instituto Geográfico Nacional (IGN), began to carry out work for the preparation of the National Topographic Map of Spain, a major project that would take almost 100 years to be completed. This work began with the measurement of geodetic bases throughout the national territory. Subsequently, the necessary topographic surveys were conducted to delimit the boundaries of municipalities, and to represent all the planimetric elements. As a part of this, surveys were carried out with topographic compasses, which allowed work to be performed at a good pace and with sufficient accuracy for cartographic purposes. The current IGN keeps in its archives all the documentation generated in the work related to the completion of this major project. The objective of this study is to extract information from this documentation on the magnetic declination measured at that time, and to evaluate it as a possible source of historic geomagnetic information for use in future works. To achieve this, we compared the recovered declination dataset with those generated for the same locations and dates using two independent sources: the Cov-Obs.x2 geomagnetic field model, which spans the last two centuries, and the declination data used to produce the first Spanish declination chart developed by the IGN at the beginning of the 20th century. The results show a clear agreement between the recovered dataset and both sources of independent declination data, suggesting that this dataset is valuable for improving our understanding of the recent geomagnetic field history and for refining main field models for the last centuries. Full article

(This article belongs to the Section Geophysics)

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20 pages, 1589 KB

Open AccessArticle

A Computational Framework for Reproducible Generation of Synthetic Grain-Size Distributions for Granular and Geoscientific Applications

by Seweryn Lipiński

Geosciences 2025, 15(12), 464; https://doi.org/10.3390/geosciences15120464 - 4 Dec 2025

Viewed by 539

Abstract

Particle size distribution (PSD), also referred to as grain-size distribution (GSD), is a fundamental characteristic of granular materials, influencing packing density, porosity, permeability, and mechanical behavior across soils, sediments, and industrial powders. Accurate and reproducible representation of PSD is essential for computational modeling, [...] Read more.

Particle size distribution (PSD), also referred to as grain-size distribution (GSD), is a fundamental characteristic of granular materials, influencing packing density, porosity, permeability, and mechanical behavior across soils, sediments, and industrial powders. Accurate and reproducible representation of PSD is essential for computational modeling, digital twin development (i.e., virtual replicas of physical systems), and machine learning applications in geosciences and engineering. Despite the widespread use of classical distributions (log-normal, Weibull, Gamma), there remains a lack of systematic frameworks for generating synthetic datasets with controlled statistical properties and reproducibility. This paper introduces a unified computational framework for generating virtual PSDs/GSDs with predefined statistical characteristics and a specified number of grain-size fractions. The approach integrates parametric modeling with two histogram-based allocation strategies: the equal-width method, maintaining uniform bin spacing, and the equal-probability method, distributing grains according to quantiles of the target distribution. Both methods ensure statistical representativeness, reproducibility, and scalability across material classes. The framework is demonstrated on representative cases of soils (Weibull), sedimentary and industrial materials (Gamma), and food powders (log-normal), showing its generality and adaptability. The generated datasets can support sensitivity analyses, experimental validation, and integration with discrete element modeling, computational fluid dynamics, or geostatistical simulations. Full article

(This article belongs to the Section Geomechanics)

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47 pages, 17932 KB

Open AccessEditor’s ChoiceArticle

Timing of Deformation in the Provence Fold-and-Thrust Belt (SE France) as Constrained by U-Pb Calcite Geochronology

by Anies Zeboudj, Olivier Lacombe, Nicolas E. Beaudoin, Jean-Paul Callot, Juliette Lamarche, Abel Guihou, Guilhem Hoareau, Gaëlle Barbotin, Christophe Pecheyran and Pierre Deschamps

Geosciences 2025, 15(12), 463; https://doi.org/10.3390/geosciences15120463 - 4 Dec 2025

Viewed by 1039

Abstract

A combination of fault and fracture analyses, paleostress reconstructions from calcite twins, and U-Pb dating of syn-kinematic calcite mineralization provides new insights into the Cretaceous–Tertiary tectonic evolution of the Provence fold-and-thrust belt. This approach helped unravel 90 million years of polyphase deformation in [...] Read more.

A combination of fault and fracture analyses, paleostress reconstructions from calcite twins, and U-Pb dating of syn-kinematic calcite mineralization provides new insights into the Cretaceous–Tertiary tectonic evolution of the Provence fold-and-thrust belt. This approach helped unravel 90 million years of polyphase deformation in this belt, which represents the eastward continuation of the northern Pyrenees. Focusing on three main targets along an NNE-SSW transect oriented roughly parallel to the regional Pyrenean shortening (the southernmost Nerthe range, the Bimont Lake area, and the northern Rians syncline), we date a wide range of scales and natures of deformation structures such as stylolites, veins, mesoscale faults, and major thrust fault zones. The reconstructed long-lasting tectonic history includes (1) the Durancian uplift and related NNE-SSW extension (~110 to 90 Ma); (2) the ~N-S Pyrenean compression related to the convergence then collision between Eurasia and Iberia and the Corsica–Sardinia block (~80 to 34 Ma); the Oligocene E-W to WNW-ESE extension related to the West European Cenozoic Rift System (ECRIS) and the Oligo–Miocene NW-SE to NNW-SSE extension related to the Liguro-Provençal Rifting (LPR); and a middle-late (?) N-S to NW-SE Alpine compression. We show that the Pyrenean shortening in Provence occurred during two main phases, 81–69 Ma and 59–34 Ma, coeval with the inversion of the pre-Pyrenean rift and the main Pyrenean collision, separated by a tectonic quiescence as described in the Pyrenees. Together with the published literature, our U-Pb ages also support the overall northward (forelandward) in sequence propagation of Pyrenean shortening across Provence. Our U-Pb results further allow us to refine the interpretation of local and regional fracture sets and reveal unsuspected polyphase development of fractures sharing a common strike. Beyond regional implications, our study shows that sampling structures of various natures and scales for U-Pb geochronology is probably the most efficient strategy to encompass the entire time interval of deformation in fold-and-thrust belts. Full article

(This article belongs to the Section Structural Geology and Tectonics)

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25 pages, 18749 KB

Open AccessArticle

Elemental Geochemical Analysis for the Gold–Antimony Segregation in the Gutaishan Deposit: Insights from Stibnite and Pyrite

by Shiyi Lu, Yongyun Ning, Liang Xiao, Ke Huang, Siqi Chen, Xuan Zhu, Hao He and Miao Yu

Geosciences 2025, 15(12), 462; https://doi.org/10.3390/geosciences15120462 - 4 Dec 2025

Viewed by 986

Abstract

In many gold–antimony deposits throughout the world, the sequence of Au and Sb precipitation varies significantly. In high-temperature systems such as hydrothermal Au deposits, gold typically precipitates prior to antimony, whereas in lower-temperature systems (e.g., Carlin-type deposits), no consistent depositional sequence is observed. [...] Read more.

In many gold–antimony deposits throughout the world, the sequence of Au and Sb precipitation varies significantly. In high-temperature systems such as hydrothermal Au deposits, gold typically precipitates prior to antimony, whereas in lower-temperature systems (e.g., Carlin-type deposits), no consistent depositional sequence is observed. The Gutaishan Au-Sb deposit, located in the Xiangzhong Basin of the Jiangnan Orogenic Belt, South China, exhibits a distinct spatial segregation within a continuously evolving system of gold and antimony mineralization—a pattern commonly observed in many Au-Sb deposits throughout the region. To elucidate the mechanisms controlling Au-Sb co-occurrence and segregation, we conducted electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) major and trace element analyses of stibnite and pyrite from quartz veins across different ore zones within the Gutaishan deposit. Trace element signatures—such as Cu-Pb correlations and Hg/(Cu + Pb) ratios which classify stibnite into Woxi-type and Xikuangshan-type, and Co/Ni ratios classifies pyrite into magmatic–hydrothermal and sedimentary types—suggest that the ore-forming fluids were predominantly magmatic–hydrothermal in origin, with minor contributions from metamorphic basement fluids. The occurrence of low-temperature trace element signatures in the Au-Sb deposit indicates that temperature is the primary control on Au-Sb segregation. The thermodynamic model further confirms that high-temperature fluids favored the precipitation of Au veins, while lower-temperature fluids facilitated the co-precipitation of stibnite and gold in Sb-Au veins. Therefore, we propose a metallogenic model for the Gutaishan deposit that highlights temperature-driven Au-Sb segregation, resulting from the progressive cooling of the ore-forming fluids. Full article

(This article belongs to the Special Issue The Application of Accessory Mineral Geochemistry in Ore Deposit Studies)

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21 pages, 2749 KB

Open AccessArticle

A Novel Poly-Potassium Salt Osmotic Technique for High-Suction Water Retention in Compacted Kaolin

by Abolfazl Baghbani, Yi Lu, Sankara Narayanan Murugesan, Hossam Abuel Naga and Eng-Choon Leong

Geosciences 2025, 15(12), 461; https://doi.org/10.3390/geosciences15120461 - 4 Dec 2025

Viewed by 337

Abstract

Accurate suction control underpins thermo-hydro-mechanical (THM) characterization of unsaturated soils, yet conventional polyethylene-glycol (PEG) osmotic methods suffer from membrane degradation, polymer intrusion, and marked temperature sensitivity. This study evaluates a potassium-neutralized poly (acrylamide-co-acrylic acid) hydrogel (PP) as a high-suction osmotic medium for water-retention [...] Read more.

Accurate suction control underpins thermo-hydro-mechanical (THM) characterization of unsaturated soils, yet conventional polyethylene-glycol (PEG) osmotic methods suffer from membrane degradation, polymer intrusion, and marked temperature sensitivity. This study evaluates a potassium-neutralized poly (acrylamide-co-acrylic acid) hydrogel (PP) as a high-suction osmotic medium for water-retention testing of compacted kaolin using a sealed cell with a grade-42 filter paper separator (no semi-permeable membrane). The water-activity–suction relation of PP was calibrated with a chilled-mirror hygrometer (WP4C) over the high-suction domain, and temperature effects were assessed between 20–30 °C. The PP imposed stable target suctions across the practical engineering range, with cross-validation to WP4C of R² ≈ 0.985 and RMSE ≈ 0.09 MPa, and exhibited modest thermal sensitivity (~2–3% per 10 °C). Mass–time records showed a two-regime equilibration (rapid first-day moisture loss then slowing to asymptote), with time to 95% equilibrium t₉₅ ≈ 3–7 days depending on suction, and equilibrium within ~2 weeks under a normalized mass change,

\frac{1}{m} |\frac{∆ m}{∆ t}| < \frac{0.1 %}{24 h}

criterion. The resulting kaolin water-retention curves are smooth soil moisture factor (SMF) reproducible, and exhibited minor wetting–drying hysteresis (~20–25% gap at matched suctions). Collectively, the results indicate that PP provides a practical, membrane-free (in the semi-permeable sense) and accurate means to control high-range suction for unsaturated soil testing, showing only modest suction variations within the tested 20–30 °C range, while mitigating long-standing PEG limitations and simplifying laboratory workflows. Full article

(This article belongs to the Special Issue Advances in Thermo-Hydro-Mechanical and Biochemical (THMBC) Characterization and Modelling of Unsaturated Soils)

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22 pages, 3717 KB

Open AccessArticle

Frequency-Dependent Slope Stability Under Earthquake Loading: A Parametric Study with Hybrid FEM–LEM

by Krzysztof Fuławka, Bogumiła Pałac-Walko and Lech Stolecki

Geosciences 2025, 15(12), 460; https://doi.org/10.3390/geosciences15120460 - 3 Dec 2025

Viewed by 439

Abstract

The correct assessment of slope stability under seismic loading requires not only the magnitude of ground acceleration to be considered but also its frequency content. In this study, a hybrid finite element/limit equilibrium (FEM–LEM) approach is used to quantify how the dominant frequency [...] Read more.

The correct assessment of slope stability under seismic loading requires not only the magnitude of ground acceleration to be considered but also its frequency content. In this study, a hybrid finite element/limit equilibrium (FEM–LEM) approach is used to quantify how the dominant frequency of harmonic ground motion affects the dynamic factor of safety, FSdyn, of a large homogeneous slope. Dynamic stresses are computed in QUAKE/W and transferred to SLOPE/W, where a FS calculation is performed at each time step to obtain FS_dyn(t). A design-of-experiment framework is applied to explore combinations of peak ground acceleration and dominant frequency. The results show that FS_dyn is much more sensitive to dominant frequency than to acceleration amplitude within the analyzed ranges, with the strongest reduction in stability occurring with the low input frequencies. Comparison with conventional pseudo-static analysis demonstrates that pseudo-static factors of safety can significantly overestimate stability at low dominant frequencies, and frequency thresholds are identified above which pseudo-static results become closer to the hybrid solution for the studied configuration. Although the model is intentionally simplified (homogeneous, drained conditions and single-frequency excitation), the findings highlight that dominant frequency is a decisive control parameter and should not be neglected in the seismic assessment of large earth structures. Full article

(This article belongs to the Topic From Earth to Innovation: Modern Trends in Mining, Geoinformation, and Geoscientific Applications)

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22 pages, 2565 KB

Open AccessArticle

The Significance of the Harirud River Basin: Sustainable Development Climate Change and Unilateral Action

by Mujib Ahmad Azizi and Jorge Leandro

Geosciences 2025, 15(12), 459; https://doi.org/10.3390/geosciences15120459 - 2 Dec 2025

Viewed by 716

Abstract

This paper examines the Harirud (Harirod, Tejen) River Basin, a vital transboundary water source shared by Afghanistan, Iran, and Turkmenistan. The basin supports farming, energy production, and home supply in a dry area. Despite its ecological, socio-economic, and geopolitical importance, the basin lacks [...] Read more.

This paper examines the Harirud (Harirod, Tejen) River Basin, a vital transboundary water source shared by Afghanistan, Iran, and Turkmenistan. The basin supports farming, energy production, and home supply in a dry area. Despite its ecological, socio-economic, and geopolitical importance, the basin lacks a cooperative governance framework, leaving it vulnerable to unilateral development, institutional weakness, and climate stress. Addressing an important research gap, this study investigates how unilateral water infrastructure and climate change jointly reshape water security and governance between Afghanistan and Iran. A qualitative case study approach integrates insights from hydropolitics, benefit sharing, and environmental security to analyse ecological and political dynamics. Findings show that climate change has disrupted hydrological regimes—average temperatures have increased by about 1.7 °C and rainfall has declined by roughly 150 mm since 1980. Unilateral dam constructions have altered seasonal flows and intensified hydro-political tensions. The study concludes that implementing Integrated Water Resources Management (IWRM), joint hydrological monitoring, climate adaptation, and equitable benefit-sharing can transform the Harirud from a contested river into a foundation for regional stability and sustainable development. Full article

(This article belongs to the Section Climate and Environment)

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28 pages, 8881 KB

Open AccessArticle

Pegmatite and Fault Spatial Distribution Patterns in Kalba-Narym Zone, East Kazakhstan: Integrated Field Observation, GIS, and Remote Sensing Analysis

by Azam Soltani Dehnavi, Syed Muzyan Shahzad, Piotr Skrzypacz and Fereshteh Shabani-Sefiddashti

Geosciences 2025, 15(12), 458; https://doi.org/10.3390/geosciences15120458 - 2 Dec 2025

Viewed by 837

Abstract

This study is an attempt to compile and complete structural features of the Kalba-Narym Zone in East Kazakhstan belonging to the western Central Asian Orogenic Belt, which is known to be well-endowed with the occurrence of pegmatite rare-metal mineralization. Remote sensing and GIS-based [...] Read more.

This study is an attempt to compile and complete structural features of the Kalba-Narym Zone in East Kazakhstan belonging to the western Central Asian Orogenic Belt, which is known to be well-endowed with the occurrence of pegmatite rare-metal mineralization. Remote sensing and GIS-based 2D are utilized to map the geological structural lineaments of faults and granitic pegmatite and pegmatite dikes. This includes lineament extraction on regional and district scales. Then, the spatial relationship between pegmatite dikes and faults is analyzed, including the lineament trends and proximity patterns. The spatial analyses are performed via the geo-computational method of Distance to Nearest Neighbors (DNN), Ripley’s L′ function, and pegmatite orientation families were employed to study the spatial distribution pattern of the pegmatites. The results of this study demonstrate that the occurrence of pegmatite dikes in various Greenfields and Brownfields of the Kalba-Narym Zone follows clustered distributions, the orientation of pegmatite swarms is dominantly NW-SE, and pegmatite emplacement is proximal to the intersection of multiple faulting systems. Extracted fault strikes, demonstrating a pronounced NW–SE to NNW–SSE structural fabric across the zone, show orientation association with the pegmatite dikes. Extraction and demarcation of pegmatites on a regional scale via remote sensing techniques help efficiently narrow down the target areas before conducting geological campaigns. This investigation proposes several new districts of pegmatite occurrence in the Kalba-Narym Zone as potential targets for exploration of critical metals. Full article

(This article belongs to the Section Structural Geology and Tectonics)

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16 pages, 4819 KB

Open AccessArticle

Estimating the Groundwater Recharge Sources to Spring-Fed Lake Ezu, Kumamoto City, Japan from Hydrochemical Characteristics

by Irfan Tsany Rahmawan, Kimpei Ichiyanagi, Haruchika Hamatake, Ilyas Nurfadhil Basuki and Teru Nagaoka

Geosciences 2025, 15(12), 457; https://doi.org/10.3390/geosciences15120457 - 2 Dec 2025

Viewed by 570

Abstract

Kumamoto is a city in Japan that relies completely on groundwater for drinking water. Groundwater in the Kumamoto region divided into shallow and deep aquifers. Around Lake Ezu, where one of Kumamoto City’s largest tap-water source wells are located, groundwater from both aquifers [...] Read more.

Kumamoto is a city in Japan that relies completely on groundwater for drinking water. Groundwater in the Kumamoto region divided into shallow and deep aquifers. Around Lake Ezu, where one of Kumamoto City’s largest tap-water source wells are located, groundwater from both aquifers mixes, resulting in numerous springs. The aim of this study was to identify and quantify the relative contributions of the groundwater sources that discharge into Ezu Lake. River, lake, spring, and artesian well samples were collected every month between April 2021 and March 2022, and groundwater chemistry data for the shallow and deep aquifers were obtained from previous studies. The NO₃⁻ and SO₄²⁻ concentrations indicated three end-members: (A) high NO₃⁻ from anthropogenic sources, (B) high SO₄²⁻ from Shirakawa River water, and (C) low NO₃⁻ and SO₄²⁻ from denitrification or dilution. Mixing analysis show 60–70% from A, 17–22% from B, and 7–25% from C for the lake waters. Also, the result showed that springs in the Kami-Ezu area were dominated by shallow aquifer water, whereas artesian wells in the Shimo-Ezu area reflected deep aquifer water. This is the first time that the contributions of groundwater sources in this area have been quantified using a three-component mixing approach. Furthermore, it was estimated that Shirakawa River infiltration, including the artificial recharge project from rice paddy, contributed approximately 57% to groundwater discharge into Ezu Lake in 2020. These results provide new insights into the contribution of artificial recharge from agricultural land to groundwater. Full article

(This article belongs to the Section Hydrogeology)

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28 pages, 26156 KB

Open AccessArticle

3D Structural Modeling and Analysis of the Devonian–Permian Succession in the Tasbulak Trough, Central Kazakhstan: Insights into Trap Formation and Preservation

by Almas Zhumagulov and Auez Abetov

Geosciences 2025, 15(12), 456; https://doi.org/10.3390/geosciences15120456 - 1 Dec 2025

Viewed by 514

Abstract

The Devonian–Permian succession of the Tasbulak Trough in the Shu–Sarysu Basin contains confirmed gas shows (wells 462, 1-P Izykyr, 1-P Sokyr-Tobe, and 1-P Kamenistaya) and a sedimentary cover exceeding 5500 m but still lacks a unified 3D structural interpretation capable of explaining the [...] Read more.

The Devonian–Permian succession of the Tasbulak Trough in the Shu–Sarysu Basin contains confirmed gas shows (wells 462, 1-P Izykyr, 1-P Sokyr-Tobe, and 1-P Kamenistaya) and a sedimentary cover exceeding 5500 m but still lacks a unified 3D structural interpretation capable of explaining the distribution of gas-prone intervals. This study addresses this gap by digitizing and integrating legacy well and 2D seismic datasets to construct horizon-consistent three-dimensional structural surfaces for eight target horizons. The resulting model reveals a low-deformation structural framework dominated by a previously undocumented element—the Central Tasbulak Ridge—which exerts first-order control on fault segmentation, trap geometry, and gas preservation. Structural surfaces were synthesized with stratigraphic intervals to define reservoir–seal–trap relationships, highlighting the late Visean–early Serpukhovian carbonate subformation as the primary target interval. Building on these relationships, a prospect evaluation matrix was developed to classify structural, stratigraphic (including intraformational), and combination trap types together with their corresponding sealing units. The results demonstrate long-term tectonic stability, multi-level evaporitic seals, and inheritance-guided trap evolution, providing a reference framework for assessing gas prospectivity in data-limited intracratonic basins and advancing understanding of petroleum-system architecture in stable continental settings. Full article

(This article belongs to the Special Issue Advanced Studies in Applied Structural Geology and Tectonics)

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23 pages, 50732 KB

Open AccessArticle

Rapid Evaluation of Coastal Sinking and Management Issues in Sayung, Central Java, Indonesia

by Dewayany Sutrisno, Ratih Dewanti Dimyati, Rizatus Shofiyati, Yosef Prihanto, Janthy Trilusianthy Hidayat, Mulyanto Darmawan, Syamsul Bahri Agus, Muhammad Helmi, Heri Sadmono and Nanin Anggraini

Geosciences 2025, 15(12), 455; https://doi.org/10.3390/geosciences15120455 - 1 Dec 2025

Viewed by 1029

Abstract

Coastal flooding driven by sea-level rise and land subsidence poses severe risks to low-lying communities. This study evaluates the causes and impacts of coastal sinking in Sayung, Demak, Central Java, using multi-temporal Landsat imagery (1977, 2024), tidal gauge data, and GPS measurements. A [...] Read more.

Coastal flooding driven by sea-level rise and land subsidence poses severe risks to low-lying communities. This study evaluates the causes and impacts of coastal sinking in Sayung, Demak, Central Java, using multi-temporal Landsat imagery (1977, 2024), tidal gauge data, and GPS measurements. A set of spectral indices—Normalized Difference Vegetation Index (NDVI), Weighted Modified Normalized Difference Water Index (WMNDWI), Land Surface Water Index (LSWI), and Normalized Difference Built-up Index (NDBI)—were calculated and integrated as input features for a Random Forest machine learning model to detect and classify environmental changes. Results indicated an average land subsidence rate of approximately 6 cm/year ± 0.8 cm/year, validated against InSAR-based measurements, and a classification accuracy of 91% (RMSE of 0.8 cm/year). A substantial decline in vegetation indices was observed, reflecting the conversion of agricultural land into built-up areas and water bodies. Extensive flooding and shoreline retreat were documented, with high-risk zones concentrated along densely developed coastlines. These findings highlight the urgent need for integrated management strategies, including stricter groundwater regulation, continuous remote-sensing-based monitoring, and large-scale mangrove restoration, to safeguard ecological functions and enhance the socio-economic resilience of coastal communities in the face of accelerating climate change impacts. Full article

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21 pages, 5142 KB

Open AccessArticle

Geological Map of the Frasassi Gorge (Northern Apennines, Italy)

by Sandro Galdenzi

Geosciences 2025, 15(12), 454; https://doi.org/10.3390/geosciences15120454 - 29 Nov 2025

Cited by 1 | Viewed by 927

Abstract

This work presents a new 1:10,000-scale geological map of the Frasassi area (central Italy), integrating recent surface and cave surveys. The map is complemented by new data on the lithostratigraphic characterisation of the Calcare Massiccio Formation (MAS), which forms the core of the [...] Read more.

This work presents a new 1:10,000-scale geological map of the Frasassi area (central Italy), integrating recent surface and cave surveys. The map is complemented by new data on the lithostratigraphic characterisation of the Calcare Massiccio Formation (MAS), which forms the core of the local Jurassic structural high. This refined analysis allows for a more detailed subdivision of the MAS and better correlation with the overlying condensed Jurassic succession (BU) and surrounding Maiolica Formation (MAI). The map documents the complex tectono-sedimentary contacts between these units, highlighting the geometry of the MAS–MAI boundary and the occurrence of neptunian dykes both at the surface and within the cave system. The proposed structural interpretation suggests that the Frasassi high was an elongated NW–SE block bounded by conjugate oblique-slip normal faults later reactivated during folding. The results refine the understanding of Jurassic paleogeography and post-Jurassic deformation in the northern Apennines and provide an updated framework to support future geological studies in the area. Full article

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21 pages, 5847 KB

Open AccessArticle

Probabilistic Slope Stability Assessment of Tropical Hillslopes in Southern Guam Under Typhoon-Induced Infiltration

by Ujwalkumar Dashrath Patil, Myeong-Ho Yeo, Sayantan Chakraborty, Surya Sarat Chandra Congress and Bryan Higgs

Geosciences 2025, 15(12), 453; https://doi.org/10.3390/geosciences15120453 - 29 Nov 2025

Viewed by 448

Abstract

Uncertainty and variability in soil properties strongly impact slope stability under extreme rainfall. This study applies a probabilistic hydro-mechanical slope stability assessment to unsaturated volcanic hillslopes in southern Guam, covering a range of slope angles and subjected to four major 2023 typhoons. The [...] Read more.

Uncertainty and variability in soil properties strongly impact slope stability under extreme rainfall. This study applies a probabilistic hydro-mechanical slope stability assessment to unsaturated volcanic hillslopes in southern Guam, covering a range of slope angles and subjected to four major 2023 typhoons. The slope scenarios analyzed include bare slopes, vegetated slopes with root water uptake, and vetiver with both uptake and root reinforcement. Laboratory-derived variability in effective cohesion, friction angle, and unit weight was incorporated via Latin hypercube sampling. Gentler slopes (≤40°) remained stable with a probability of failure (PoF) = 0%. For steep slopes (45–60°), vetiver root reinforcement improved the mean factor of safety by up to 12–15% and reduced variability in outcomes to less than 2%. Probabilistic predictions advanced failure timing compared to deterministic estimates, with differences more pronounced on steeper slopes. By integrating soil variability and vegetation effects within probabilistic frameworks, this approach provides a more accurate and comprehensive assessment of tropical slope failure risks, thereby informing more effective and resilient slope management strategies. Full article

(This article belongs to the Special Issue Advances in Thermo-Hydro-Mechanical and Biochemical (THMBC) Characterization and Modelling of Unsaturated Soils)

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16 pages, 9349 KB

Open AccessArticle

Surface Ice Velocity near the Terminus of Grey Glacier in the Southern Patagonian Icefield, Based on Direct Field Measurements

by Roberto García-Esteban

Geosciences 2025, 15(12), 452; https://doi.org/10.3390/geosciences15120452 - 29 Nov 2025

Viewed by 1405

Abstract

Glacier mass balance and ice flow dynamics, strongly influenced by climatic variability, topography, and geological–structural controls, can be precisely characterized through in situ GPS measurements of surface ice velocity, though such data remain limited due to logistical challenges in field acquisition. This study [...] Read more.

Glacier mass balance and ice flow dynamics, strongly influenced by climatic variability, topography, and geological–structural controls, can be precisely characterized through in situ GPS measurements of surface ice velocity, though such data remain limited due to logistical challenges in field acquisition. This study presents direct measurements of surface ice velocity on Grey Glacier, a major outlet glacier of the Southern Patagonian Icefield (SPI) in Chile. Ice flow was monitored over a one-week period in late 2002 by tracking the displacement of six stakes installed on the glacier surface. The resulting velocity data reveal spatial patterns of surface flow that provide significant information for the comparison and validation of remote sensing observations, which is particularly relevant considering that the ice mass from which the data were collected has since disappeared due to glacier retreat. The combined use of ground-based and remote sensing methods is essential for advancing our understanding of glacier motion and behavior, particularly in the context of climate forcing. Full article

(This article belongs to the Section Cryosphere)

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26 pages, 42537 KB

Open AccessArticle

ID-TIMS U-Pb Zircon Ages and Petrogenesis of Granitoid Magmas in Central Madagascar: Geodynamic Perspectives

by Tsilavo Raharimahefa, Christine Rasoazanamparany and Timothy M. Kusky

Geosciences 2025, 15(12), 451; https://doi.org/10.3390/geosciences15120451 - 28 Nov 2025

Viewed by 468

Abstract

We present ID-TIMS U-Pb single zircon ages and major and trace element data for granitoid plutons from the Imorona–Itsindro and Kiangara suites in central Madagascar, in order to constrain the timing of igneous emplacement and investigate the petrogenesis and tectonic settings of these [...] Read more.

We present ID-TIMS U-Pb single zircon ages and major and trace element data for granitoid plutons from the Imorona–Itsindro and Kiangara suites in central Madagascar, in order to constrain the timing of igneous emplacement and investigate the petrogenesis and tectonic settings of these Neoproterozoic plutons. A U-Pb crystallization age of 779 ± 7 Ma was determined from an Imorona–Itsindro intrusion, while a Kiangara intrusion yields 777 ± 4 Ma, older than previously reported. The identical U-Pb ages suggest contemporaneous emplacement of some Kiangara and Imorona–Itsindro intrusions. Elemental data indicate that the two suites display trace element patterns similar to those of arc-type magmas. Some distinct geochemical features are apparent between these two suites. The Imorona–Itsindro sample displays I-type affinity with low REE abundances, whereas the Kiangara samples exhibit A-type signatures with higher REE contents. We suggest that the elemental differences between A-type and I-type reflect the contamination of mantle-derived magma by lower and upper crustal rocks, respectively. We suggest that the coeval A-type and I-type granitoids in central Madagascar were generated in a subduction system associated with slab rollback and back-arc extension like extension. The compositional diversity in these Neoproterozoic plutons reflects the evolution of the tectonic regime within a single geodynamic environment, similar to that proposed for plutons in other Precambrian and younger terranes. Full article

(This article belongs to the Section Geochemistry)

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4 pages, 151 KB

Open AccessEditorial

Special Issue “Earth Observation by GNSS and GIS Techniques”

by Aggeliki Kyriou, Lia Bárbara Cunha Barata Duarte and Christos Pikridas

Geosciences 2025, 15(12), 450; https://doi.org/10.3390/geosciences15120450 - 28 Nov 2025

Viewed by 516

Abstract

Over the past few decades, Geographic Information Systems (GIS) and Global Navigation Satellite Systems (GNSS) have undergone transformative developments that have profoundly influenced positioning/navigation, data science, and geospatial technologies [...] Full article

(This article belongs to the Special Issue Earth Observation by GNSS and GIS Techniques)

19 pages, 13143 KB

Open AccessArticle

Research on the Impact of Regional-Scale Soil Mechanics Parameter Disturbances on Rainfall Landslides Warning

by Kai Wang, Shuailong Xie, Linmao Xie, Shaojie Zhang, Lin Zhu, Fuzhou Qi, Haohao Luo and Xiangyang Zhao

Geosciences 2025, 15(12), 449; https://doi.org/10.3390/geosciences15120449 - 27 Nov 2025

Viewed by 288

Abstract

The spatial uncertainty of soil mechanical parameters remains a major challenge in physical models for the prediction of rainfall landslides. Currently, the widely adopted stochastic methods for parameter selection disregard the lithological variations and fail to account for rainfall infiltration’s attenuation effects on [...] Read more.

The spatial uncertainty of soil mechanical parameters remains a major challenge in physical models for the prediction of rainfall landslides. Currently, the widely adopted stochastic methods for parameter selection disregard the lithological variations and fail to account for rainfall infiltration’s attenuation effects on soil mechanical parameters. Through field sampling and laboratory testing, this study examined the distribution of mechanical parameters across five lithological zones in Fengjie County, Chongqing, China. The soil mechanical parameters at liquid and plastic limits were used as boundaries, and nine attenuation scenarios of mechanical parameters were devised based on disturbance ratios from 0.1 to 0.9, simulating the attenuation effect of rainfall infiltration on parameters. The prediction performance across different attenuation scenarios was then explored. The findings revealed that different lithologies displayed unique normal distribution characteristics. Prediction results from slope units indicate lower disturbance ratios (0.1–0.3) yield ideal miss rates (below 10%) but very high false alarm rates. With higher disturbance ratios (0.4–0.9), missing alarm rates increased while false alarm rates continually decreased. At 0.4 disturbance ratio, both the false and missed alarm rates are optimal. This study recommends setting the disturbance ratio of soil mechanical parameters to 0.4 to achieve a preferable predictive performance in Fengjie County. Full article

(This article belongs to the Special Issue Landslides: The Contribution of Multi-Source Multi-Temporal Data for Monitoring, Analysis and Risk Mitigation)

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38 pages, 13323 KB

Open AccessReview

Pockmark Distribution and Genesis in the Mediterranean and Black Seas: A Regional Synthesis

by Daniele Spatola, Martin Torvald Hovland, Daniele Casalbore, Marzia Rovere, Francesco Latino Chiocci, Stéphanie Dupré, Gemma Ercilla, Aaron Micallef, George Papatheodorou, Attilio Sulli and Juan Tomás Vázquez

Geosciences 2025, 15(12), 448; https://doi.org/10.3390/geosciences15120448 - 27 Nov 2025

Viewed by 1097

Abstract

Pockmarks are ubiquitous seafloor depressions formed by the fluid/gas seepage through marine sediments, with implications for geohazards, benthic ecosystems, and climate-related processes. Despite extensive research, the mechanisms controlling the formation and spatial distribution of pockmarks are not completely understood, owing to the diverse [...] Read more.

Pockmarks are ubiquitous seafloor depressions formed by the fluid/gas seepage through marine sediments, with implications for geohazards, benthic ecosystems, and climate-related processes. Despite extensive research, the mechanisms controlling the formation and spatial distribution of pockmarks are not completely understood, owing to the diverse and site-specific geo-environmental conditions. In this study, we provide a first review of over 7500 pockmarks mapped across the Mediterranean and Black seas, showing their relationship with depth range, slope gradient, seafloor lithology, proximity to tectonic faults, and sediment thickness. Our analysis reveals that pockmarks are predominantly located at intermediate water depths (100–700 m), with two main clusters around 100–200 and 500–700 m. They are commonly found on gently sloping seafloor (<4°), often clustering around slope breaks. In detail, two slope-related peaks around 1.5° and 3.5° suggest distinct geological settings for pockmark formation: sediment-rich and low-energy environments versus more dynamic slope domains. Fault proximity plays a critical role, with over 40% of pockmarks occurring within 1 km of mapped faults, indicating that structural discontinuities act as preferential fluid pathways. Pockmarks concentrate in areas with moderate Plio-Quaternary sediment thickness (300–600 m), suggesting an optimal window for overpressure generation and fluid expulsion. A strong lithological control is evident: 74% of pockmarks occur on muddy sand or sand-rich substrates. In terms of ongoing to recent seepage/activity, ~27% of pockmarks show evidence of ongoing fluid seepage (e.g., acoustic gas flares, seismic wipeouts), particularly in regions such as the Black Sea, Aegean, and Central Tyrrhenian, where faulting, salt tectonics, or hydrothermal systems enhance permeability. Conversely, pockmarks in the Western Mediterranean appear to be generally inactive and buried. These findings underscore the influence of tectono-sedimentary architecture on seafloor fluid escape and provide essential insight into methane seepage, slope stability, and benthic habitats. This pedagogic review enhances our understanding of pockmark systems and establishes a foundation for future geohazard assessment, climate studies, and marine resource exploration. Full article

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