Geosciences

26 pages, 66564 KB

Open AccessArticle

Prediction of Sonic Well Logs Using Deep Neural Network: Application to Petroleum Reservoir Characterization in Mexico

by Jorge Alejandro Vázquez-Ayala, Jose Carlos Ortiz-Alemán, Sebastian López-Juárez, Carlos Couder-Castañeda and Alfredo Trujillo-Alcántara

Geosciences 2025, 15(11), 424; https://doi.org/10.3390/geosciences15110424 - 6 Nov 2025

Abstract

The sonic log is a key tool for assessing the mechanical properties of rocks, identifying structural features, calibrating seismic data, and monitoring well integrity. However, sonic data are often incomplete due to time and cost constraints, tool failures, or unreliable measurements. Traditional approaches [...] Read more.

The sonic log is a key tool for assessing the mechanical properties of rocks, identifying structural features, calibrating seismic data, and monitoring well integrity. However, sonic data are often incomplete due to time and cost constraints, tool failures, or unreliable measurements. Traditional approaches to generate synthetic sonic logs usually rely on empirical relationships or statistical methods. In this study, we applied an artificial intelligence approach in which a deep neural network was trained with real data from an oilfield in Mexico to reconstruct sonic logs based on their relationships with other geophysical well logs. Three models, each using different input logs, were trained to predict the sonic response. The models were validated on wells excluded from training, and performance was evaluated using the root mean square error (RMSE) and mean absolute percentage error (MAPE), showing satisfactory accuracy. The models achieved RMSE values between 1.4 and 1.7 [

μ

s/ft] and MAPE values between 2.1 and 2.6% on independent test wells, confirming robust predictive performance. We also generated synthetic sonic logs for wells where no sonic data were originally acquired, demonstrating the practical value of the proposed method. This work integrates convolutional (CNN) and recurrent (GRU) layers in a single deep-learning architecture, trained under strict well-level validation. The workflow is demonstrated on wells from the Tabasco Basin, representing a field-scale deployment not previously reported in similar studies. Full article

(This article belongs to the Section Geophysics)

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23 pages, 15275 KB

Open AccessArticle

Geological Modelling of Urban Environments Under Data Uncertainty

by Charalampos Ntigkakis, Stephen Birkinshaw and Ross Stirling

Geosciences 2025, 15(11), 423; https://doi.org/10.3390/geosciences15110423 - 5 Nov 2025

Abstract

Geological models form the basis for scientific investigations of both the surface and subsurface of urban environments. Urban cover, however, usually prohibits the collection of new subsurface data. Therefore, models depend on existing subsurface datasets that are often of poor quality and have [...] Read more.

Geological models form the basis for scientific investigations of both the surface and subsurface of urban environments. Urban cover, however, usually prohibits the collection of new subsurface data. Therefore, models depend on existing subsurface datasets that are often of poor quality and have an uneven spatial and temporal distribution, introducing significant uncertainty. This research proposes a novel method to mitigate uncertainty caused by clusters of uncertain data points in kriging-based geological modelling. This method estimates orientations from clusters of uncertain data and randomly selects points for geological interpolation. Unlike other approaches, it relies on the spatial distribution of the data and translating geological information from points to geological orientations. This research also compares the proposed approach to locally changing the accuracy of the interpolator through data-informed local smoothing. Using the Ouseburn catchment, Newcastle upon Tyne, UK, as a case study, results indicate good correlation between both approaches and known conditions, as well as improved performance of the proposed methodology in model validation. Findings highlight a trade-off between model uncertainty and model precision when using highly uncertain datasets. As urban planning, water resources, and energy analyses rely on a robust geological interpretation, the modelling objective ultimately guides the best modelling approach. Full article

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14 pages, 2510 KB

Open AccessArticle

Experimental Study on the Mechanical Response and Failure Behavior of High-Pressure Frozen Ice Under Axial Loading Conditions

by Zhijiang Yang, Yu Zhang, Tao Han, Ying Ding, Chenyi Zhang and Weihao Yang

Geosciences 2025, 15(11), 422; https://doi.org/10.3390/geosciences15110422 - 5 Nov 2025

Abstract

The mechanical response and failure behavior of high-pressure frozen ice are essential to the technological progress in drilling thick polar ice sheets, but current research primarily focuses on non-pressure-frozen ice. In this paper, ice specimens with a cylindrical geometry were fabricated at −20 [...] Read more.

The mechanical response and failure behavior of high-pressure frozen ice are essential to the technological progress in drilling thick polar ice sheets, but current research primarily focuses on non-pressure-frozen ice. In this paper, ice specimens with a cylindrical geometry were fabricated at −20 °C, applying freezing pressures across a range of 10 to 40 MPa with a 10 MPa interval. Their mechanical properties were investigated through triaxial compression tests under axial loading conditions and were compared with the results obtained at −10 °C. The results indicate that, with increasing freezing pressure, the samples transitioned from a failure state of interlaced cracking to a highly transparent state. The failure behavior observed in the specimens was characterized as ductile, as evidenced by the deviatoric stress–axial strain relationships. Moreover, the peak deviatoric stress exhibited a non-monotonic dependence on freezing pressure, with an initial rise from 9.59 MPa at 10 MPa to a peak of 14.37 MPa at 30 MPa and a subsequent decline to 10.12 MPa at 40 MPa. All specimens reached a relatively stable residual state at 5% axial strain, with residual deviatoric stresses ranging from 4.13 to 5.71 MPa. A reduction in freezing temperature from −10 °C to −20 °C can effectively enhance both the peak deviatoric stress and the residual stress of high-pressure frozen ice under triaxial shear conditions. All peak tangent modulus values, ranging from 1.61 to 2.93 GPa with an average of 2.2 GPa, were observed within 0.7% axial strain and exhibited mild fluctuations with increasing freezing pressure. These findings provide a more robust mechanical foundation for drilling research and operations in extremely thick polar ice caps. Full article

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13 pages, 47202 KB

Open AccessArticle

Coseismic Deformation, Fault Slip Distribution, and Stress Changes of the 2025 M_S 6.8 Dingri Earthquake from Sentinel-1A InSAR Observations

by Junwen Zhu, Bo Zhang, Saisai Yao and Yimeng Cai

Geosciences 2025, 15(11), 421; https://doi.org/10.3390/geosciences15110421 - 5 Nov 2025

Abstract

On 7 January 2025, a M_S 6.8 earthquake struck Dingri County, southern Tibet, within the extensional regime of the central Himalaya–southern Tibetan Plateau. Using ascending and descending Sentinel-1A SAR data, we applied a two-pass Differential InSAR (D-InSAR) approach with SRTM DEM data [...] Read more.

On 7 January 2025, a M_S 6.8 earthquake struck Dingri County, southern Tibet, within the extensional regime of the central Himalaya–southern Tibetan Plateau. Using ascending and descending Sentinel-1A SAR data, we applied a two-pass Differential InSAR (D-InSAR) approach with SRTM DEM data to retrieve high-precision coseismic deformation fields. We observed significant LOS deformation, revealing peak displacements of −1.06 m and +0.76 m, with deformation concentrated along the Denmo Co graben and clear offsets along its western boundary fault. Nonlinear inversion using the Okada elastic dislocation model and a quadtree down-sampled dataset yields a rupture plane 28.42 km long and 12.81 km wide, striking 183.51°, dipping 55.41°, and raking −71.95°, consistent with a predominantly normal-faulting mechanism with a minor left-lateral component. Distributed-slip inversion reveals that peak slip (4.79 m) was concentrated in the upper ~10 km of the fault, with the main asperity located in the central fault segment. The seismic moment is estimated to be 4.24 × 10¹⁹ Nm, which corresponds to a magnitude of M_W 7.05. Coulomb failure stress (ΔCFS) calculations indicate stress increases (>0.01 MPa) at the northern and southern rupture terminations (5–10 km depth) and the flanks at 15–20 km depth, suggesting elevated seismic potential in these regions. This integrated InSAR–modeling–stress analysis provides new constraints on the source parameters, slip distribution, and tectonic implications of the 2025 Dingri earthquake, offering important insights for regional seismic hazard assessment. Full article

(This article belongs to the Section Geophysics)

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17 pages, 2720 KB

Open AccessArticle

Studying Natural Radioactivity of Coals and Ash and Slag Waste as Potential Raw Materials for Quality Assessment and Extraction of Rare Earth Elements

by Yuriy Pak, Dmitriy Pak, Pyotr Kropachev, Vladimir Matonin, Diana Ibragimova, Anar Tebayeva, Pavel Timoshenko, Natalya Tsoy and Yelena Tseshkovskaya

Geosciences 2025, 15(11), 420; https://doi.org/10.3390/geosciences15110420 - 4 Nov 2025

Abstract

A significant portion of coal mined in Kazakhstan is mainly used for fuel energy and metallurgy. Approximately 60% of electricity is generated by coal-fired power engineering. About 19 million tons of ash and slag waste (ASW) are annually sent to dumps. After coal [...] Read more.

A significant portion of coal mined in Kazakhstan is mainly used for fuel energy and metallurgy. Approximately 60% of electricity is generated by coal-fired power engineering. About 19 million tons of ash and slag waste (ASW) are annually sent to dumps. After coal combustion, in ASW not only are natural radioactive nuclides NRN (U²³⁸, Th²³², K⁴⁰) concentrated, but also rare and rare earth elements (REE). In this regard, ASW that essentially turns into quasi-technogenic deposits of NRN and REE, requires systemic measures for their utilization. The possibilities of extracting REE from coal power-industry waste are estimated based on the analysis of the concentration of REE (Ce, La, Nd, Sm, etc.), NRN (U²³⁸, Th²³² and their decay products, K⁴⁰) and the established significant correlations between rare earth and radioactive elements. The purpose of this paper is to study the natural radioactivity of coals and ash and slag waste as potential raw materials for assessing the quality and extracting rare earth metals. The stated purpose involves solving the following problems: studying the features of the NRN and REE distribution in coals and ash and slag waste; assessing the possibility of using ash and slag waste as a promising source of REE extraction based on nuclear radiometric studies; and studying the spectrometry of natural gamma radiation for assessing the quality of coals. Full article

(This article belongs to the Topic Global Challenges and Local Solutions in Natural Resource Management: Insights from the GEA 2025 Conference)

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23 pages, 4754 KB

Open AccessArticle

Unveiling the Igneous Geodiversity of the Shunku Rumi Geosite for Geoeducation and Geotourism Actions in the Napo Sumaco UNESCO Global Geopark (Ecuador)

by Saida Huatatoca-Mamallacta, Marco Simbaña-Tasiguano, David Granja-Guato, Ronny Espín, Lola De Lima, Pablo Cisneros, Andrea Salgado-Revelo, Estefany Almeida and Alexia Tana

Geosciences 2025, 15(11), 419; https://doi.org/10.3390/geosciences15110419 (registering DOI) - 4 Nov 2025

Abstract

The Shunku Rumi Geosite, located within the Napo Sumaco UNESCO Global Geopark in Ecuador, offers an exceptional opportunity to explore the igneous geodiversity of the Abitagua Batholith. This study employs an integrative approach combining petrographic, geochemical, and structural analyses to characterize the site’s [...] Read more.

The Shunku Rumi Geosite, located within the Napo Sumaco UNESCO Global Geopark in Ecuador, offers an exceptional opportunity to explore the igneous geodiversity of the Abitagua Batholith. This study employs an integrative approach combining petrographic, geochemical, and structural analyses to characterize the site’s lithological diversity, mineral assemblages, and emplacement mechanisms. Detailed fieldwork at a 1:3000 scale included geological mapping, 23 intrusive rock samples, and over 100 structural measurements. Laboratory techniques, such as X-ray fluorescence (XRF), X-ray diffraction (XRD), and thin-section petrography, revealed a wide range of mineral phases, with dominant minerals including quartz, plagioclase, biotite, and amphibole. The petrographic and geochemical dataset is consistent with a calc-alkaline affinity, reflecting subduction-related magmatism. Alteration zones, predominantly propylitic, were identified through secondary minerals like epidote, chlorite, and sericite, signaling late-stage hydrothermal processes. Structural analysis shows NE–SW dyke emplacement was controlled by pre-existing fault systems. The study emphasizes the educational and geotourism potential of Shunku Rumi, with its accessible exposures offering a unique platform for geoeducation. These results also underpin the development of field-based learning materials and practitioner guides within the geopark, linking geological processes to local cultural heritage and promoting sustainable development. The findings contribute to the growing efforts to integrate scientific research with community engagement, fostering a deeper understanding of Earth’s dynamic systems within the context of the Amazonian landscape. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: "Trends and Prospects in Geoheritage, Geoparks, and Geotourism")

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35 pages, 5292 KB

Open AccessArticle

3D Simultaneous Inversion and Modeling of Full Tensor Gravity and Gravity Data for Salt Imaging

by Carlos Ortiz-Alemán, Sebastian López-Juárez, Carlos Couder-Castañeda, Alfredo Trujillo-Alcántara, Jaime Meléndez-Martínez and Andrés Ambros-Vargas

Geosciences 2025, 15(11), 418; https://doi.org/10.3390/geosciences15110418 - 3 Nov 2025

Abstract

In this study, we performed three-dimensional gravity modeling and inversion of the Vinton Dome, a well-known onshore salt structure located in southwestern Louisiana, USA, by simultaneously integrating Full Tensor Gravity (FTG) and conventional gravity data using a simulated-annealing approach. The process begins with [...] Read more.

In this study, we performed three-dimensional gravity modeling and inversion of the Vinton Dome, a well-known onshore salt structure located in southwestern Louisiana, USA, by simultaneously integrating Full Tensor Gravity (FTG) and conventional gravity data using a simulated-annealing approach. The process begins with the application of Tensor Euler Deconvolution (ETD), which provides a physically consistent initial model for inversion. This method extends the traditional Euler deconvolution by incorporating both the three diagonal components of the gravity-gradient tensor and the three components of the gravity field, thereby enhancing the frequency content and stability of the solutions. By combining FTG gradients and gravity data, the proposed workflow improves the precision of subsurface modeling, particularly in delineating salt-body boundaries and estimating their depth. The integration of ETD-derived initialization with joint inversion results in a more accurate reconstruction of density contrasts, offering a powerful approach for characterizing complex geologic structures such as the Vinton Dome. Full article

(This article belongs to the Section Geophysics)

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19 pages, 2719 KB

Open AccessArticle

Explainable Machine Learning-Based Ground Motion Characterization: Evaluating the Role of Geotechnical Variabilities on Response Parameters

by Ayele Tesema Chala, Richard Ray, Mais Mayassah, Janko Logar and Edina Koch

Geosciences 2025, 15(11), 417; https://doi.org/10.3390/geosciences15110417 - 2 Nov 2025

Abstract

Accounting for geotechnical property variability is crucial in seismic site response analysis. Traditionally, the influence of each geotechnical property on response parameters is assessed independently. However, this approach limits our understanding of the combined effects of multiple properties on ground response parameters. This [...] Read more.

Accounting for geotechnical property variability is crucial in seismic site response analysis. Traditionally, the influence of each geotechnical property on response parameters is assessed independently. However, this approach limits our understanding of the combined effects of multiple properties on ground response parameters. This study presents a novel, explainable machine learning (ML)-based approach to assess the influence of multiple geotechnical property variations on response parameters. Four ML models, namely AdaBoost, Extreme Gradient Boosting (XGBoost), Random Forest Regressor (RFR) and Gradient Boosting Machine (GBM), were developed for predictive models. The input factors were shear-wave velocity, plasticity index, soil thickness, input motion intensity and unit weight of the soils. The response parameters were peak ground acceleration (PGA) and peak ground displacement (PGD). Multiple statistical performance metrics were computed to evaluate the performance of the models. The results show the superior prediction performance of the GBM model with low error rates and high agreement index (AI), Kling–Gupta efficiency (KGE) and coefficient of determination

{(R}^{2})

. The output of the GBM model was further analyzed using Shapley Additive exPlanation (SHAP) technique to explain and identify the most significant factors contributing to the predictions. Finally, the model was used to develop user-friendly web-based software to facilitate rapid predictions of PGA and PGD. Full article

(This article belongs to the Section Geomechanics)

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12 pages, 2344 KB

Open AccessArticle

Revealing a Previously Unknown Fault Hidden by Urbanization: A Case Study from Villa d’Agri (Southern Italy)

by Alessandro Giocoli and Nicola Perilli

Geosciences 2025, 15(11), 416; https://doi.org/10.3390/geosciences15110416 - 1 Nov 2025

Abstract

Urbanization poses significant challenges for fault investigation, as it can obscure or even hide surface fault expressions and limit access to potential study sites. This paper reports the preliminary results of Electrical Resistivity Tomography combined with geological field surveys in the urbanized area [...] Read more.

Urbanization poses significant challenges for fault investigation, as it can obscure or even hide surface fault expressions and limit access to potential study sites. This paper reports the preliminary results of Electrical Resistivity Tomography combined with geological field surveys in the urbanized area of Villa d’Agri (Marsicovetere, Basilicata Region, Southern Italy), which has undergone significant expansion in recent decades. This area is located at the northeastern border of the High Agri Valley, characterized by the Eastern Agri Fault System, one of the fault systems believed to have caused the M 7.0 earthquake in 1857 in Southern Italy. The combined use of Electrical Resistivity Tomography and geological field investigations in previously inadequately explored areas, along with the reprocessing of data provided by the technical office of Marsicovetere, allowed imaging of a previously unknown fault and reconstruction of sedimentary cover and substratum geometries, particularly in the urban and peri-urban sectors of Villa d’Agri. These preliminary findings provide valuable insights for geological and structural studies and have prompted the attention of the municipal decision makers, supporting further research aimed at enhancing urban management and seismic risk assessment. Full article

(This article belongs to the Section Geophysics)

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15 pages, 6136 KB

Open AccessArticle

Petrology of Lancang (Upper Mekong) River Sand

by Daxin Fang, Xiumian Hu, Eduardo Garzanti, Wen Lai and Fengting Chen

Geosciences 2025, 15(11), 415; https://doi.org/10.3390/geosciences15110415 - 31 Oct 2025

Abstract

The texture and composition of river sediments are key to understanding the characteristics of source rocks, chemical weathering in the source area, physical modifications during transport, and human impacts within watersheds. This study analyzes 47 very fine to coarse size sands from the [...] Read more.

The texture and composition of river sediments are key to understanding the characteristics of source rocks, chemical weathering in the source area, physical modifications during transport, and human impacts within watersheds. This study analyzes 47 very fine to coarse size sands from the Lancang (Upper Mekong) River in China to monitor compositional variations and assesses the contribution of different geological units to trunk-river sediments. Lancang River sands are mostly feldspatho-quartzo-lithic in composition, with quartz content increasing downstream at the expense of lithic fragments (especially of carbonate lithics). Sand is mostly generated from the Lincang and Baoshan blocks, with subordinate contributions from the Simao and Changdu blocks. This study provides new insights into erosional and depositional processes in the Lancang River and emphasizes the impact of human activities on river sediment transport. Full article

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

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21 pages, 15740 KB

Open AccessArticle

A Dual-Method Assessment of the Yarmouk Basin’s Groundwater Vulnerability Using SINTACS and Random Forest

by Ibraheem Hamdan, Ahmad AlShdaifat, Majed Ibrahim, Abdel Rahman Al-Shabeeb, Rida Al-Adamat and A’kif Al-Fugara

Geosciences 2025, 15(11), 414; https://doi.org/10.3390/geosciences15110414 - 30 Oct 2025

Abstract

Water scarcity and increased human pressures are crucial issues facing Jordan. Chemical pollutants significantly influence groundwater quality in Jordan due to increased pollution risks, ease of contamination, and various human activities that release harmful compounds into the groundwater. The Yarmouk River Groundwater Basin [...] Read more.

Water scarcity and increased human pressures are crucial issues facing Jordan. Chemical pollutants significantly influence groundwater quality in Jordan due to increased pollution risks, ease of contamination, and various human activities that release harmful compounds into the groundwater. The Yarmouk River Groundwater Basin (YRB) is one of the main basins in northern Jordan. It is exploited for domestic, drinking, agricultural, and industrial uses. This study assessed the groundwater vulnerability for the YRB through the implementation of a dual-method approach, employing the SINTACS intrinsic groundwater vulnerability model and the Random Forest (RF) machine learning method. The results revealed similarities and differences between the two models. The delineation of low-vulnerability zones was similar, suggesting that the intrinsic hydrogeological characteristics of these areas provide robust natural protection against contamination. In addition, both models suggest that the eastern, northern, and southern parts are areas of ‘high’ and ‘very high’ vulnerability. Subtle differences can be observed, particularly in the precise delineation of boundaries and the fragmentation of vulnerability zones. Generally, the results show that over (47%) and (43%) of the basin area falls into the high- and very high-vulnerability classes, while the very low and low classes make up about (14%) and (15%), based on the SINTACS and RF models, respectively. Using the SINTACS and RF groundwater vulnerability assessments in the YRB provides valuable insights into groundwater susceptibility in this critical area of Jordan. The identified high- and very high-vulnerability areas within YRB highlight the urgent need for protective measures to safeguard this vital groundwater resource for both present and future generations. The SINTACS model proves to be a reliable tool for intrinsic vulnerability assessment in the study area, consistent with its application in other parts of Jordan and similar dry regions. Full article

(This article belongs to the Special Issue Advancing Groundwater Sustainability: Integrated Risk Assessment and Management Strategies)

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16 pages, 10175 KB

Open AccessArticle

Upwellings and Mantle Ponding Zones in the Lower Mantle Transition Zone (660–1000 km)

by Jean-Paul Montagner, Barbara Romanowicz, Mathurin Wamba and Gael Burgos

Geosciences 2025, 15(11), 413; https://doi.org/10.3390/geosciences15110413 - 30 Oct 2025

Abstract

Convective instabilities at various boundary layers in the earth’s mantle—including the core–mantle boundary, mantle transition zone and lithosphere-asthenosphere boundary— result in upwellings (mantle plumes) and downwellings (subducting slabs). While hotspot volcanism is traditionally linked to mantle plumes, their structure, origins, evolution, and death [...] Read more.

Convective instabilities at various boundary layers in the earth’s mantle—including the core–mantle boundary, mantle transition zone and lithosphere-asthenosphere boundary— result in upwellings (mantle plumes) and downwellings (subducting slabs). While hotspot volcanism is traditionally linked to mantle plumes, their structure, origins, evolution, and death remain subjects of ongoing debate. Recent progress in seismic tomography has revealed a complex plumbing system connecting the core–mantle boundary and the surface. In particular, recent seismic imaging results suggest the presence of large-scale ponding zones between 660 km and ∼1000 km, associated with several mantle plumes around the globe. The broad upwellings originating from the CMB spread laterally beneath the 660 km seismic discontinuity, forming extensive ponding zones several thousand kilometers wide and extending up from an approximately 1000 km depth. Similar ponding zones are also observed for downwellings, with stagnant subducting slabs, within the 660–1000 km depth range. Here, we review evidence for wide ponding zones characterized by low seismic velocities and anomalous radial and azimuthal anisotropies in light of recent high-resolution regional studies below La Réunion Island in the Indian Ocean and below St Helena/Ascension in the southern Atlantic Ocean. We review and discuss possible interpretations of these structures, as well as possible mineralogical, geodynamic implications and outlook for further investigations aiming to improve our understanding of the mantle plumbing system. Full article

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

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15 pages, 8296 KB

Open AccessArticle

Grain Shape Variation of Different Sand-Sized Particles and Its Implication for Discriminating Sedimentary Environment

by Fangen Hu and Xia Xiao

Geosciences 2025, 15(11), 412; https://doi.org/10.3390/geosciences15110412 - 29 Oct 2025

Abstract

Particle shape analysis is essential in sedimentological research, as it offers vital insights into the sedimentary environment and transport history. However, little is known about the particle shape variation across different sand fractions, as well as the differences between particle shape data based [...] Read more.

Particle shape analysis is essential in sedimentological research, as it offers vital insights into the sedimentary environment and transport history. However, little is known about the particle shape variation across different sand fractions, as well as the differences between particle shape data based on volume and number weighting. In this study, we investigate the grain shape variation of different sand-sized particles (fine, medium, and coarse sand fractions) in aeolian dune (11 samples) and lake beach (12 samples) environments around Poyang Lake, China, using dynamic image analysis (DIA). The shape data results based on both volume-weighted and number-weighted methods reveal significant differences in shape parameters (circularity, symmetry, aspect ratio, and convexity) among different sand fractions, especially between coarse and fine sand. This highlights the critical need for size-fractionated analysis when employing particle shape as an environmental discriminant. By integrating 86 sets of published particle shape data from different depositional environments, we found that volume-weighted shape data has limited ability to differentiate beach and dune sands, although it distinguished the fluvial, desert dune, and coastal beach sand well. In contrast, number-weighted shape data effectively distinguished the beach and dune sands, as fine sand particles are typically transported in suspension during fluvial processes and in saltation during aeolian processes. This demonstrates the role of integrating both volume-weighted and number-weighted shape data in future studies to accurately distinguish sedimentary environments. Full article

(This article belongs to the Section Climate and Environment)

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38 pages, 36010 KB

Open AccessReview

Cobalt-Rich Fe-Mn Crusts in the Western Pacific Magellan Seamount Trail: Geochemistry and Chronostratigraphy

by Igor S. Peretyazhko, Elena A. Savina and Irina A. Pulyaeva

Geosciences 2025, 15(11), 411; https://doi.org/10.3390/geosciences15110411 - 27 Oct 2025

Abstract

Synthesis of published and new data from the Govorov and Kocebu guyots provide geochemical and chronostratigraphic constraints on hydrogenetic cobalt-rich Fe-Mn crusts from the Western Pacific Magellan Seamount Trail (MST). The history of the crusts began about 65–60 Ma, when the relict layer [...] Read more.

Synthesis of published and new data from the Govorov and Kocebu guyots provide geochemical and chronostratigraphic constraints on hydrogenetic cobalt-rich Fe-Mn crusts from the Western Pacific Magellan Seamount Trail (MST). The history of the crusts began about 65–60 Ma, when the relict layer R was deposited in the Campanian—Maastrichtian and Late Paleocene along the shores of guyots. The growth of the old-generation crusts continued in the Late Paleocene—Early Eocene (Layer I-1) and in the Middle—Late Eocene (Layer I-2) in a shallow-water shelf environment. The younger layers formed in the Late Oligocene—Early Miocene (Layer I-2b), Miocene (Layer II), and Pliocene—Pleistocene (Layer III) at depths about the present sea level. The precipitation of Fe and Mn oxyhydroxides from seawater was interrupted by several times, with the longest gap from 38 to 26.5 Ma between the old (R, I-1, and I-2) and young (I-2b, II, and III) layers. Fe and Mn oxyhydroxides in the crusts were affected by two global events of phosphogenesis in the Pacific: Late Eocene—Early Oligocene, from 43 to 39 Ma (Layers R, I-1, I-2) and Late Oligocene—Early Miocene, from 27 to 21 Ma (Layer I-2b). The trace element patterns in different layers of the Co-rich Fe-Mn crusts are grouped using factor analysis of principal components (varimax raw) into four factors: (1) +(all REEs except Ce and La); (2) +(Ce, La, Ba, Mo, Sr, Pb); (3) +(Zr, Hf, Nb, Rb, As)/-Pb; (4) +(U, Th, Co, As, Sb, W)/-Y. The factor score diagrams highlight fields which are especially contrasting for Layers I-1, I-2, and II + III according to factors 2 and 4. Consistent REE and Y variations in Layers I-2b → II → III of the crust from Pallada Guyot correlate with gradual ocean deepening between the Late Oligocene—Early Miocene and Present when the MST guyots were submerging. Large variations in the trace element contents across coeval layers may be due to the hydrodynamics of currents on the guyot surfaces. Furthermore, the geochemistry of the crusts bears effects from repeated episodes of Cenozoic volcanism in the MST region of the Pacific Plate. Higher contents of Nb, Zr, As, Sb, and W in the younger layers II and III may result from large-scale volcanism, including Miocene eruptions of petit-spot volcanoes. Full article

(This article belongs to the Section Geochemistry)

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13 pages, 815 KB

Open AccessArticle

A Bayesian Geostatistical Approach to Analyzing Groundwater Depth in Mining Areas

by Maria Chrysanthi, Andrew Pavlides and Emmanouil A Varouchakis

Geosciences 2025, 15(11), 410; https://doi.org/10.3390/geosciences15110410 - 25 Oct 2025

Abstract

This study addresses the spatial variability of groundwater levels within a mining basin in Greece. The objective is to develop an accurate spatial model of groundwater levels in the area to support an integrated groundwater management plan. Hydraulic heads were measured in 72 [...] Read more.

This study addresses the spatial variability of groundwater levels within a mining basin in Greece. The objective is to develop an accurate spatial model of groundwater levels in the area to support an integrated groundwater management plan. Hydraulic heads were measured in 72 observation wells, which are irregularly distributed, primarily in mining zones. Multiple geostatistical approaches are evaluated to identify an optimal model based on cross-validation metrics. We introduce a novel trend model that includes the surface elevation gradient, as well as the proximity of wells to the riverbed, utilizing a modified Box–Cox transformation to normalize residuals. The results indicate that Regression Kriging with a non-differentiable Matérn variogram outperforms Ordinary Kriging in cross-validation accuracy. The study provides maps of the piezometric head and kriging variance within a Bayesian framework, being among the first to quantify and incorporate river-distance effects within regression kriging for groundwater. Full article

(This article belongs to the Section Hydrogeology)

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19 pages, 4635 KB

Open AccessCommunication

Research on High-Density Discrete Seismic Signal Denoising Processing Method Based on the SFOA-VMD Algorithm

by Xiaoji Wang, Kai Lin, Guangzhao Guo, Xiaotao Wen and Dan Chen

Geosciences 2025, 15(11), 409; https://doi.org/10.3390/geosciences15110409 - 25 Oct 2025

Abstract

With the increasing demand for precision in seismic exploration, high-resolution surveys and shallow-layer identification have become essential. This requires higher sampling frequencies during seismic data acquisition, which shortens seismic wavelengths and enables the capture of high-frequency signals to reveal finer subsurface structural details. [...] Read more.

With the increasing demand for precision in seismic exploration, high-resolution surveys and shallow-layer identification have become essential. This requires higher sampling frequencies during seismic data acquisition, which shortens seismic wavelengths and enables the capture of high-frequency signals to reveal finer subsurface structural details. However, the insufficient sampling rate of existing petroleum instruments prevents the effective capture of such high-frequency signals. To address this limitation, we employ high-frequency geophones together with high-density and high-frequency acquisition systems to collect the required data. Meanwhile, conventional processing methods such as Fourier transform-based time–frequency analysis are prone to phase instability caused by frequency interval selection. This instability hinders the accurate representation of subsurface structures and reduces the precision of shallow-layer phase identification. To overcome these challenges, this paper proposes a denoising method for high-sampling-rate seismic data based on Variational Mode Decomposition (VMD) optimized by the Starfish Optimization Algorithm (SFOA). The denoising results of simulated signals demonstrate that the proposed method effectively preserves the stability of noise-free regions while maintaining the integrity of peak signals. It significantly improves the signal-to-noise ratio (SNR) and normalized cross-correlation coefficient (NCC) while reducing the root mean square error (RMSE) and relative root mean square error (RRMSE). After denoising the surface mountain drilling-while-drilling signals, the resulting waveforms show a strong correspondence with the low-velocity zone interfaces, enabling clear differentiation of shallow stratigraphic distributions. Full article

(This article belongs to the Section Geophysics)

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22 pages, 3482 KB

Open AccessArticle

Analysis of Ionospheric Response and GNSS Positioning on Geodetic and Low-Cost Receivers in Mexico During the May 2024 Geomagnetic Storm

by J. Rene Vazquez-Ontiveros, Angela Melgarejo-Morales, Carlos A. Martinez-Felix and J. Ramon Martinez-Batlle

Geosciences 2025, 15(11), 408; https://doi.org/10.3390/geosciences15110408 - 22 Oct 2025

Abstract

Geomagnetic storms can severely disturb the ionosphere, degrading Global Navigation Satellite System (GNSS) performance, particularly at low latitudes. The 10 May 2024 superstorm produced a strong ionospheric response across Mexico, with well-defined positive and negative phases observed at all analyzed stations. The proximity [...] Read more.

Geomagnetic storms can severely disturb the ionosphere, degrading Global Navigation Satellite System (GNSS) performance, particularly at low latitudes. The 10 May 2024 superstorm produced a strong ionospheric response across Mexico, with well-defined positive and negative phases observed at all analyzed stations. The proximity in time of %dTEC peaks to the second and third steps of the storm’s main phase, together with their local time dependence, indicates that Prompt Penetration Electric Fields (PPEFs) dominated the initial positive phase on the dayside. These eastward electric fields uplifted the F-region plasma, enhancing TEC values—especially at northern stations, where increases reached ±180%. In contrast, the subsequent nighttime depletion and extended recovery were mainly driven by composition-related plasma loss and enhanced recombination. A suppression of TEC followed the positive phase, with depletions between −58% and −77%, showing a persistent latitudinal gradient. Low-cost GNSS receivers successfully captured these ionospheric signatures but exhibited higher positioning degradation—up to 50% greater than geodetic-grade receivers. Multi-constellation Precise Point Positioning (PPP) mitigated these effects, reducing 3D errors by up to 23% and 53% in geodetic and low-cost receivers, respectively. These findings reveal the day–night dependence of ionospheric storm phases and underscore the importance of regional multi-GNSS monitoring during extreme space weather. Full article

(This article belongs to the Section Geophysics)

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16 pages, 14567 KB

Open AccessArticle

Subsidence in Qinghai—Tibet Plateau Peatlands Driven by Drainage Disturbance and Climatic Variability

by Enpeng Tian, Zhenshan Xue, Yanfeng Wu, Kaishan Song, Ruxu Li and Rongyang Zhang

Geosciences 2025, 15(11), 407; https://doi.org/10.3390/geosciences15110407 - 22 Oct 2025

Abstract

Peatlands are globally important carbon sinks, yet these are increasingly threatened by climate change and human disturbances. Among degradation indicators, surface subsidence is gradual and challenging to monitor, particularly in alpine peatlands. This study applied SBAS-InSAR techniques to analyze surface deformation in the [...] Read more.

Peatlands are globally important carbon sinks, yet these are increasingly threatened by climate change and human disturbances. Among degradation indicators, surface subsidence is gradual and challenging to monitor, particularly in alpine peatlands. This study applied SBAS-InSAR techniques to analyze surface deformation in the Zoige peatland of the eastern Qinghai—Tibet Plateau using Sentinel-1 SAR data from 2017 to 2023. The results showed a maximum interannual subsidence of −167.92 mm and a peak seasonal deformation of −144.11 mm, with a cumulative average of −23.99 mm (−3.43 mm·yr⁻¹). Approximately 80.9% of peatlands within the protected area exhibited subsidence. Drainage ditch construction emerged as the dominant driver, while climatic factors such as precipitation and temperature exhibited seasonal effects. Subsidence was more pronounced in drier years and during winter months. These findings highlight the spatial heterogeneity and seasonal dynamics of peatland subsidence and underscore the urgent need for hydrological restoration and long-term monitoring to mitigate degradation in alpine peatland ecosystems. Full article

(This article belongs to the Section Climate and Environment)

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39 pages, 23544 KB

Open AccessArticle

Zircon Isotopic Constraints on Age, Magma Genesis, and Evolution of the Betic Ophiolites, Nevado-Filábride Complex, Spain

by Encarnación Puga, Antonio Díaz de Federico, Miguel A. Díaz Puga and José Miguel Nieto

Geosciences 2025, 15(10), 406; https://doi.org/10.3390/geosciences15100406 - 20 Oct 2025

Abstract

Metabasic rocks (eclogites and amphibolites) from four Betic ophiolite outcrops (Lugros, Almirez, Cóbdar, and Algarrobo), comprising Ol-Px gabbros, dolerites, and MORB-affinity basalts, were studied. U-Pb SHRIMP zircon dating yielded Early to Middle Jurassic ages (187–174 Ma). At Cóbdar and Algarrobo, several magmatic levels [...] Read more.

Metabasic rocks (eclogites and amphibolites) from four Betic ophiolite outcrops (Lugros, Almirez, Cóbdar, and Algarrobo), comprising Ol-Px gabbros, dolerites, and MORB-affinity basalts, were studied. U-Pb SHRIMP zircon dating yielded Early to Middle Jurassic ages (187–174 Ma). At Cóbdar and Algarrobo, several magmatic levels were identified (187 ± 1.7 to 174 ± 1.8 Ma, and 184 ± 1.8 to 180 ± 1.6 Ma, respectively). In Lugros, two gabbros were dated to 187 ± 2.5 and 184 ± 1.4 Ma, while a dolerite dyke intruding serpentinites in Almirez gave 184 ± 1.6 Ma. Algarrobo xenocrystic zircons, predominantly Precambrian, resemble those from the MAR (13° N–15° N) in age and chemistry, suggesting a similar tectonic setting. δ¹⁸O values (4.2–6.2‰) of Betic ophiolite zircons (gabbros, basalts, dolerites) match those of MAR and SWIR samples, reflecting also oceanic alteration. Some zircons preserve δ¹⁸O variations linked to Jurassic (~150 Ma) oceanic metamorphism and later orogenic overprints. REE patterns show depletions in HREE and Y, with localized enrichments in LREE and Hf, which are more marked in metamorphically recrystallized zones. Xenocrystic zircons may derive from Precambrian protoliths assimilated during Jurassic magma ascent near transform faults. This integrated geochronological and geochemical evidence provides the key constraints for a revised geodynamic framework, confirming the existence of a Betic Jurassic ocean basin, which is a crucial precursor to the Alpine orogenic events that shaped the region. Full article

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

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