Geosciences

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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18 pages, 3181 KB

Open AccessArticle

Effect of Matrix Properties and Pipe Characteristics on Internal Erosion in Unsaturated Clayey Sand Slope

by Olaniyi Afolayan, Anna Lancaster and Jack Montgomery

Geosciences 2025, 15(10), 405; https://doi.org/10.3390/geosciences15100405 - 17 Oct 2025

Viewed by 147

Abstract

Soil piping is the process by which subsurface water creates and enlarges channels, or “pipes,” within soil, enabling rapid and preferential flow beneath the surface. The collapse of these eroded pipes can lead to land degradation, gully formation, and potential damage to overlying [...] Read more.

Soil piping is the process by which subsurface water creates and enlarges channels, or “pipes,” within soil, enabling rapid and preferential flow beneath the surface. The collapse of these eroded pipes can lead to land degradation, gully formation, and potential damage to overlying infrastructure. While the structural consequences of pipe collapse are well recognized, there is limited understanding of the factors controlling pipe collapse and how water within the pipe influences moisture levels within a slope. This study used physical models of unsaturated slopes to examine how compaction conditions, pipe characteristics, and hydraulic conditions affect the progression of internal erosion. Models were created with different initial pipe sizes, moisture contents, densities at compaction and levels of pipe connectivity. Volumetric water content (VWC) sensors and cameras were used to monitor the slope response to subsurface flow, and measurements of pipe geometry were collected after the tests. Results showed that lower initial soil water content was more susceptible to pipe collapse, while higher water content showed improved pipe stability and sustained preferential flow. Fully connected pipes grew through erosion due to the pipe flow, while disconnected pipes grew mainly through local pipe collapse. Hydraulic equilibrium and soil erodibility affected the final pipe morphology more than the initial pipe size. These experimental results demonstrate that soil fabric and hydraulic connectivity of the pipe control the progression of piping, likelihood of collapse, and movement of water within the soil matrix. Full article

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17 pages, 32699 KB

Open AccessArticle

Evaluation of a Soviet-Era Gravimetric Survey Using Absolute Gravity Measurements and Global Gravity Models: Toward the First National Geoid of Kazakhstan

by Daniya Shoganbekova, Asset Urazaliyev, Roman Sermiagin, Serik Nurakynov, Magzhan Kozhakhmetov, Nailya Zhaksygul and Anel Islyamova

Geosciences 2025, 15(10), 404; https://doi.org/10.3390/geosciences15100404 - 17 Oct 2025

Viewed by 254

Abstract

Determining a high-precision national geoid is a fundamental step in modernizing Kazakhstan’s vertical reference system. However, the country’s vast territory, complex topography, and limited coverage of modern terrestrial and airborne gravimetric surveys present significant challenges. In this context, Soviet-era gravimetric maps at a [...] Read more.

Determining a high-precision national geoid is a fundamental step in modernizing Kazakhstan’s vertical reference system. However, the country’s vast territory, complex topography, and limited coverage of modern terrestrial and airborne gravimetric surveys present significant challenges. In this context, Soviet-era gravimetric maps at a 1:200,000 scale remain the only consistent nationwide data source, yet their reliability has not previously been rigorously assessed within modern gravity standards. This study presents the first comprehensive validation of Soviet-era gravimetric surveys using two independent approaches. The first approach is about the comparison of gravity anomalies with the global geopotential models EGM2008, EIGEN-6C4 and XGM2019e_2159. The second approach is about the direct evaluation against absolute gravity measurements from the newly established Qazaqstan Gravity Reference Frame (QazGRF). The analysis demonstrates that, after applying systematic corrections, the Soviet-era gravimetric survey retains high information content. The mean discrepancy with QazGRF measurements is 0.7 mGal with a standard deviation of 2.5 mGal, and more than 90% of the evaluated points deviate by less than ±5 mGal. Larger inconsistencies, up to 20 mGal, are confined to mountainous and geophysically complex regions. In addition, several artifacts inherent to the global models were identified, suggesting that the integration of validated regional gravimetric data can also support future improvements of global gravity models. A key finding was the detection of an artifact in the global models on sheet M43. Its presence was confirmed by comparison with terrestrial gravimetric data and inter-model differences. It was established that the anomaly is caused by inaccuracies in the terrestrial “fill-in” component of the EGM2008 model, which subsequently inherited by later global solutions. The results confirm that Soviet gravimetric maps, once critically re-evaluated and tied to absolute observations, can be effectively integrated with global models. This integration delivers reliable, high-resolution inputs for regional gravity-field modeling. It establishes a robust scientific and practical foundation for constructing the first national geoid of Kazakhstan and for implementing a unified state coordinate and height system. It also helps enhance the accuracy of global geopotential models. Full article

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26 pages, 3740 KB

Open AccessArticle

Pilot Study on Fingerprinting the Isotopic Signatures of Fossiliferous Limestones as a Tool for Forensic Investigation of Fossil Trafficking (Cretaceous Crato Formation, Brazil)

by Marcos Antônio Pimentel de Sousa, Daniel Rodrigues do Nascimento Junior, Anelize Manuela Bahniuk and Giovanna Della Porta

Geosciences 2025, 15(10), 403; https://doi.org/10.3390/geosciences15100403 - 16 Oct 2025

Viewed by 120

Abstract

Unauthorized fossil trafficking violates national legislation and deprives cultural and natural heritage. This study proposes a pilot method to fingerprint the origin of fossils by characterizing the carbon and oxygen stable isotope signatures of fossil-bearing limestones to provide a non-destructive quantitative tool against [...] Read more.

Unauthorized fossil trafficking violates national legislation and deprives cultural and natural heritage. This study proposes a pilot method to fingerprint the origin of fossils by characterizing the carbon and oxygen stable isotope signatures of fossil-bearing limestones to provide a non-destructive quantitative tool against illegal fossil trade. This promising approach has been applied to the Crato Formation (NE Brazil), which is a renowned Lower Cretaceous fossiliferous lacustrine limestone. This study aims at establishing the range of isotopic oxygen (δ¹⁸O) and carbon (δ¹³C) values of the Crato Formation’s laminated calci-mudstone by compiling isotopic data from previous studies, conducting new analyses, and comparing with other fossiliferous lacustrine limestones from Brazil (Cretaceous Codó Formation) and the USA (Eocene Green River Formation). This preliminary evaluation determined a distinctive isotopic signature of the Crato Formation fossil-bearing “sete cortes” (“seven cuts”) ethnostratum, with VPDB δ¹⁸O and δ¹³C arithmetic means of −5.94‰ and +0.90‰, standard deviations 0.76‰ and 0.61‰, medians of −5.89‰ and +0.73‰, and interquartile ranges of 1.47‰ and 1.24‰, respectively. This pilot investigation establishes a methodological groundwork for the development of a global database integrating lithofacies and geochemical parameters of fossil-bearing limestones to expedite the identification and restitution of illegally extracted paleontological heritage. Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: “Sedimentology and Stratigraphy”)

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17 pages, 9762 KB

Open AccessArticle

Reconstruction of Torrential Activity in Cerradillas Valley (Sierra de Guadarrama National Park, Spain) Using Dendrogeomorphic Techniques

by Esteban Collazos Fernández and Juan M. Rubiales

Geosciences 2025, 15(10), 402; https://doi.org/10.3390/geosciences15100402 - 16 Oct 2025

Viewed by 140

Abstract

Flash floods in Mediterranean mountain catchments are a significant natural hazard, but systematic historical records of their occurrence are often lacking. This study reconstructs the history of torrential activity in the previously unexplored Arroyo Cerradillas catchment in the Sierra de Guadarrama, Spain, to [...] Read more.

Flash floods in Mediterranean mountain catchments are a significant natural hazard, but systematic historical records of their occurrence are often lacking. This study reconstructs the history of torrential activity in the previously unexplored Arroyo Cerradillas catchment in the Sierra de Guadarrama, Spain, to better understand the event frequency and its triggers. The main methods involved dendrogeomorphological analysis of growth disturbances in Scots pine (Pinus sylvestris L.) trees. Torrential events were dated and their intensity assessed by identifying and cross-dating scars, reaction wood, and abrupt changes in growth, which were integrated into a weighted index. The results yielded a chronology of 12 significant torrential events between 1935 and 2003. This record shows strong coherence with regional studies but also highlights the localized nature of some floods, and it adds two previously undocumented event years (1998 and 2003) to the regional chronology. The 1996 event was identified as having exceptional magnitude. This study confirms the value of dendrogeomorphology for completing historical flood records and improving hazard assessments. The intense signal from 1996 was likely caused by widespread mechanical damage from snow and wind rather than a direct hydrological flood, demonstrating the complexity of interpreting geomorphic processes in mountain environments. Full article

(This article belongs to the Section Natural Hazards)

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24 pages, 458 KB

Open AccessReview

Overview of Thermo-Hydro-Mechanical Constitutive Models for Saturated Cohesive Soils

by Meysam Mashayekhi and Victor N. Kaliakin

Geosciences 2025, 15(10), 401; https://doi.org/10.3390/geosciences15100401 - 15 Oct 2025

Viewed by 130

Abstract

The need to mathematically model and numerically simulate the effect of temperature on the hydro-mechanical behavior of soils, driven by the increased interest in energy geostructures and sundry other geothermal systems, has necessitated the development of constitutive models that can realistically simulate the [...] Read more.

The need to mathematically model and numerically simulate the effect of temperature on the hydro-mechanical behavior of soils, driven by the increased interest in energy geostructures and sundry other geothermal systems, has necessitated the development of constitutive models that can realistically simulate the thermo-hydro-mechanical (THM) behavior of such materials. Many such models, possessing varying degrees of sophistication, have been developed since the 1970s. A detailed overview and critical assessment of such models has not, however, been presented. In order to address this shortcoming and to better understand the models’ relative strengths and limitations, a comprehensive overview and assessment of constitutive models that have been developed to simulate the THM behavior of saturated cohesive soils is presented in this paper. Full article

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14 pages, 3810 KB

Open AccessArticle

Evidence of Ejecta from the Late-Triassic Manicouagan Impact in the Blomidon Formation, Fundy Basin, Canada

by Lawrence H. Tanner, Michael J. Clutson and David E. Brown

Geosciences 2025, 15(10), 400; https://doi.org/10.3390/geosciences15100400 - 15 Oct 2025

Viewed by 210

Abstract

The Manicouagan impact structure in northeastern Canada is one of the largest, well-documented impact sites among Phanerozoic structures. Once considered a candidate for the cause of end-Triassic extinctions, radioisotopic dating of impact melt rock has established the age of the impact as middle [...] Read more.

The Manicouagan impact structure in northeastern Canada is one of the largest, well-documented impact sites among Phanerozoic structures. Once considered a candidate for the cause of end-Triassic extinctions, radioisotopic dating of impact melt rock has established the age of the impact as middle to late Norian. In contrast to the clearly defined association between the Chicxulub structure and the K-Pg boundary, however, the sedimentary record of the Manicouagan impact is unusually sparse, with verified ejecta deposits currently limited to a single deep-marine occurrence (Japan) and one well-documented deposit in a continental (fluvial) setting (England). Sedimentary layers at the top of a widespread seismically deformed zone in a continental sequence in the Upper Triassic (Norian) Blomidon Formation, Fundy Basin, contain sparse, potentially impact-derived grains (shocked quartz and spherulitic grains) that are interpreted as impact ejecta that were reworked within a playa-lacustrine environment. The presence of these ejecta suggests that the seismic deformation resulted indirectly from the Manicouagan impact via reactivation of a nearby fault system. Paleomagnetic correlation of the ejecta-bearing strata in the Blomidon Formation to the Newark astrochronostratigraphic polarity time scale suggests a temporal discrepancy in the correlation of the Newark time scale to the magnetostratigraphic record of the Upper Triassic. This hypothesis is supported by recent correlations of the geomagnetic polarity time scale to the Newark time scale. Full article

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

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1 pages, 126 KB

Open AccessCorrection

Correction: Moussallam, Y. Carbon Isotopes in Magmatic Systems: Measurements, Interpretations, and the Carbon Isotopic Signature of the Earth’s Mantle. Geosciences 2025, 15, 266

by Yves Moussallam

Geosciences 2025, 15(10), 399; https://doi.org/10.3390/geosciences15100399 - 15 Oct 2025

Viewed by 84

Abstract

The Editorial Office was informed of several errors in the published version compared to the author’s original version [...] Full article

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

19 pages, 18396 KB

Open AccessArticle

Composition and Genesis of Dark Dolomite-Type Nephrite in the Kavokta Deposit, Middle Vitim Mountain Country, Russia

by Evgeniy V. Kislov, Irina Yu. Kotova, Viktor F. Posokhov, Artem V. Trofimov and Elena A. Khromova

Geosciences 2025, 15(10), 398; https://doi.org/10.3390/geosciences15100398 - 14 Oct 2025

Viewed by 132

Abstract

The Kavokta deposit in Russia contains gray and black dolomite-type nephrite, which is in high demand commercially. Although the fact that black nephrite has been found in several deposits, the reasons for its color are not well understood. The present study aims to [...] Read more.

The Kavokta deposit in Russia contains gray and black dolomite-type nephrite, which is in high demand commercially. Although the fact that black nephrite has been found in several deposits, the reasons for its color are not well understood. The present study aims to identify the localization and mineral composition of gray and black nephrite, and to determine the reasons for its dark coloration. The mineral composition of nephrite was studied using a scanning electron microscope with energy-dispersive microanalysis (SEM-EDX) and X-ray phase analysis. Also, the isotopic composition of carbon in graphite in nephrite and in carbonates associated with nephrite in the surrounding strata was determined. The gray–black color in most samples from the southeastern part of the Kavokta deposit (lodes 17 and 28 of the nephrite-bearing zone 4 of the Medvezhy section and lode 6-1 of the nephrite-bearing zone 6 of the Levoberezhny section) is due to the presence of graphite. Syngenetic graphite formed both by the organic matter buried in dolomites and by the decomposition of carbon dioxide that is released during decarbonation under the influence of deep-seated hydrogen. The color of nephrite also depends on the iron content, changing from white to light green as the iron content increases. The gray color of tremolite–diopside nephrite is due to the development of chlorite aggregates that replace diopside and/or tremolite. The gray-green to black color of the nephrite in the northwestern part of the Kavokta deposit (lode 1 of the nephrite-bearing zone 1 of the Prozrachny section) is due to the high iron content in the tremolite–actinolite at the contact with the epidote–tremolite skarn formed after amphibolite. The identified patterns of black nephrite localization can be used in the process of geological exploration of similar deposits elsewhere in Russia and abroad. Full article

(This article belongs to the Section Geochemistry)

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26 pages, 18752 KB

Open AccessArticle

Rate-Dependent Residual Strength of Unsaturated Slip-Zone Soil Under Suction-Controlled Conditions

by Jin Yuan, Rui Zhu, Yanpian Mao, Lanlan Xu, Jianfan Zhao, Chao Zhang and Shu Zhang

Geosciences 2025, 15(10), 397; https://doi.org/10.3390/geosciences15100397 - 14 Oct 2025

Viewed by 182

Abstract

Reservoir landslides undergo saturated–unsaturated transitions under hydrological variations. Matric suction significantly influences slip-zone soil strength. Existing studies lack analysis of suction–rate–strength coupling, while Amontons’ model fails for cohesive soils. This study investigated Huangtupo landslide slip-zone soil in the upper reaches of the Yangtze [...] Read more.

Reservoir landslides undergo saturated–unsaturated transitions under hydrological variations. Matric suction significantly influences slip-zone soil strength. Existing studies lack analysis of suction–rate–strength coupling, while Amontons’ model fails for cohesive soils. This study investigated Huangtupo landslide slip-zone soil in the upper reaches of the Yangtze River using pressure plate and saturated salt solution methods to determine the soil–water characteristic curve. Suction-controlled ring shear tests were conducted under three matric suction levels (

Ψ

= 0, 200, and 700 kPa) across net normal stresses (

σ_{n e t}

= 100–800 kPa) and shear rates (

\dot{γ}

= 0.05–200 mm/min). Key findings revealed the following: (1) significant suction–rate coupling effects were shown, with 700 kPa suction yielding 30% higher residual strength than saturated conditions, validating matric suction’s role in enhancing effective stress and particle contact strength; (2) residual cohesion showed strong logarithmic correlation with shear rate, with the fastest growth below 10 mm/min, while the residual friction angle varied minimally (0.68°), contributing little to overall strength; (3) a bivariate model relating residual cohesion to

\dot{γ}

and

Ψ

was established, overcoming traditional single-factor limitations. The study demonstrates that dual-parameter Coulomb modeling effectively captures multi-field coupling mechanisms in unsaturated slip-zone soils, providing theoretical foundations for landslide deformation prediction and engineering design under dynamic hydrological conditions. Full article

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

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22 pages, 17373 KB

Open AccessArticle

Numerical Modeling for Costa Rica of Tsunamis Originating from Tonga–Kermadec and Colombia–Ecuador Subduction Zones

by Silvia Chacón-Barrantes, Fabio Rivera-Cerdas, Kristel Espinoza-Hernández and Anthony Murillo-Gutiérrez

Geosciences 2025, 15(10), 396; https://doi.org/10.3390/geosciences15100396 - 13 Oct 2025

Viewed by 258

Abstract

Costa Rica has experienced 45 tsunamis at both its Pacific and Caribbean coasts, with none to moderated impact. However, the coastal population has increased exponentially in the past few decades, which might lead to higher impact in future tsunamis. In 2018 and 2019, [...] Read more.

Costa Rica has experienced 45 tsunamis at both its Pacific and Caribbean coasts, with none to moderated impact. However, the coastal population has increased exponentially in the past few decades, which might lead to higher impact in future tsunamis. In 2018 and 2019, IOC/UNESCO organized Experts Meetings of Tsunami Sources, Hazards, Risks and Uncertainties associated with the Tonga–Kermadec and Colombia–Ecuador subduction zones, where experts defined maximum credible scenarios. Here we modeled the propagation of those tsunami scenarios to Costa Rica and their inundation for selected sites. We found that the Tonga–Kermadec scenarios provoked more inundation than previous modeled sources from that region. However, the large travel time for those scenarios, about 14 h, would allow for a timely evacuation. In the Colombia–Ecuador scenarios, they provoked less inundation than previously modeled sources from that region, a good outcome as their arrival time is between 75 and 150 min. These new results required the update of tsunami evacuation maps and/or plans for many communities but provided more favorable conditions for tsunami preparedness. Yet, the short arrival times of the Colombia–Ecuador scenarios still require a prompt response from the population and authorities. For this, additional to updated tsunami evacuation maps and plans, it is recommended to have tsunami exercises on a regular basis. Full article

(This article belongs to the Collection Tsunamis: From the Scientific Challenges to the Social Impact)

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27 pages, 1859 KB

Open AccessArticle

Strengths and Weaknesses of Artificial Intelligence in Exploring Asbestos History and Regulations Across Countries

by Alessandro Croce, Francesca Ugo, Annalisa Roveta, Carlotta Bertolina, Caterina Rinaudo, Antonio Maconi and Marinella Bertolotti

Geosciences 2025, 15(10), 395; https://doi.org/10.3390/geosciences15100395 - 12 Oct 2025

Viewed by 245

Abstract

Asbestos, consisting of six natural mineral fibrous silicate phases, was widely utilized in industrial development during the 20th century and has left a global legacy of health, environmental, and regulatory challenges. Its remarkable properties (e.g., heat resistance, sound absorption, and tensile strength) made [...] Read more.

Asbestos, consisting of six natural mineral fibrous silicate phases, was widely utilized in industrial development during the 20th century and has left a global legacy of health, environmental, and regulatory challenges. Its remarkable properties (e.g., heat resistance, sound absorption, and tensile strength) made it a useful material in numerous applications. However, scientific research revealed its serious health risks in the early 1900s, with growing evidence during the 1960s, and nowadays its role in the development of different diseases (e.g., respiratory diseases, such as lung cancer, mesothelioma, and asbestosis) is well defined. Mapping this complex history requires integrating heterogeneous and often inconsistent information from nearly 200 countries. In this study, we tested the use of generative artificial intelligence (AI) tools as exploratory and comparative instruments to support the collection of asbestos-related data worldwide. Using Google Gemini (version 2.5 flash) and OpenAI ChatGPT (GPT-4-turbo variant), we gathered historical, medical, and regulatory information and then systematically verified and contextualized it with expert analysis. This dual approach allowed us to assess both the global asbestos situation and the reliability, advantages, and limitations of AI-assisted research. Our results highlight how AI can accelerate data collection and provide useful first drafts while underscoring the necessity of human expertise for validation, interpretation, and critical integration. This study, therefore, contributes a dual perspective: a comprehensive overview of the asbestos legacy across countries and a methodological reflection on the opportunities and pitfalls of employing AI in geoscientific and environmental research. Full article

(This article belongs to the Section Natural Hazards)

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30 pages, 20586 KB

Open AccessArticle

A Shallow Water Case of Ordovician Marine Red Beds (South China): Evidence from Sedimentary Structures and Response to the Kwangsian Orogeny

by Liangjun Wu, Xiqiang Quan, Yuanhai Zhang, Pujun Wang and Chao Huang

Geosciences 2025, 15(10), 394; https://doi.org/10.3390/geosciences15100394 - 12 Oct 2025

Viewed by 166

Abstract

Ordovician marine red beds (OMRBs) are widely developed along the margins of Gondwana and represent distinctive limestone facies. These red beds are known for their diverse sedimentary structures and have been described by scholars as the “fashionable facies” in geological history. However, their [...] Read more.

Ordovician marine red beds (OMRBs) are widely developed along the margins of Gondwana and represent distinctive limestone facies. These red beds are known for their diverse sedimentary structures and have been described by scholars as the “fashionable facies” in geological history. However, their characteristics and classification remain controversial. Multiple hypotheses about their origin have also hindered a clear understanding of these strata. Therefore, this study focuses on the Xiangxi area (South China) and presents a detailed analysis of the sedimentary structures of marine red beds, building on previous research on OMRBs in South China. Based on genetic features, we divide the most debated “nodule-like” and “cracked” structures—previously identified by earlier researchers—into ten subtypes. Three key genetic end-members are identified among these subtypes: breccia, patch, and argillaceous band. Detailed studies using microslab analysis, scanning electron microscopy, geochemistry, and paleontology were carried out on these three end-members. The results confirm that the Ordovician marine red beds were mainly deposited in a shallow marine environment, with the red coloration primarily derived from continental sources. As the sea level rose, the color of the red beds lightened, and the dominant sedimentary structures shifted from breccia end-members to argillaceous band end-members. Additionally, this study identified a vertically penetrating argillaceous band controlled by syndepositional compressive stress, which may be linked to NW-directed compression from the Kwangsian Orogeny. Evidence from tectonic styles, biofacies migration, and chronostratigraphy supports this hypothesis. Full article

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

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56 pages, 37807 KB

Open AccessReview

Geological and Geographical Characteristics of Limestone and Karst Landforms in Japan: Insights from Akiyoshidai, Seiyo (Shikoku), and Okinoerabu Island

by Koji Wakita, Takashi Murakami, Tomohiro Tsuji and Kensaku Urata

Geosciences 2025, 15(10), 393; https://doi.org/10.3390/geosciences15100393 - 11 Oct 2025

Viewed by 723

Abstract

Limestone in Japan exhibits distinct distribution patterns and associated lithologies compared to limestone found in most other parts of the world. These differences reflect contrasting depositional settings and formation processes. While the majority of the world’s limestones originate from reefs and their detritus [...] Read more.

Limestone in Japan exhibits distinct distribution patterns and associated lithologies compared to limestone found in most other parts of the world. These differences reflect contrasting depositional settings and formation processes. While the majority of the world’s limestones originate from reefs and their detritus deposited on continental shelves adjacent to continents, most limestones in Japan are derived from atoll reefs formed on oceanic island basalts. The remainder developed as reefs and associated detritus along the margins of island arcs underlain by continental crust. In this study, we refer to the former as Accreted Oceanic Reef (AOR) Limestones and the latter as Autochthonous Arc-Shelf (AAS) Limestones. These two types not only differ in origin and depositional environment, but also in the development of karst landforms, including cave systems. AOR Limestones, typified by the Akiyoshi Limestone of Akiyoshidai and the Shikoku Karst, partly distributed in Seiyo (Shikoku), and Pre-Cenozoic AAS Limestones such as Torinosu Limestone of Seiyo (Shikoku) exhibit complex three-dimensional structures that contrast with various caves common worldwide. In contrast, Cenozoic AAS Limestones are exemplified by the Pleistocene Ryukyu Limestone of Okinoerabu Island, where caves, though relatively small, develop parallel to bedding planes. While differing in scale from many caves worldwide, their fundamental structures are comparable. These contrasting characteristics provide new insights into the geological and geomorphological diversity of limestone and karst landforms in Japan. Full article

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17 pages, 15251 KB

Open AccessArticle

What Do Fossil charophytes Whisper to Us? Palaeoecological and Palaeoenvironmental Reports from Pleistocene Continental Deposits of Umbria (Central Italy)

by Angela Baldanza, Paola Angelini, Anna Maria De Santis, Isabella Nalli and Roberto Bizzarri

Geosciences 2025, 15(10), 392; https://doi.org/10.3390/geosciences15100392 - 10 Oct 2025

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Abstract

The Early Pleistocene continental deposits of the Tiberino Basin (Central Italy) host exceptionally preserved fossil charophyte assemblages that provide critical insights into palaeoenvironmental and palaeoclimatic dynamics during a key phase of the Mediterranean evolution. Integrated micropalaeontological and sedimentological investigations at three reference sections [...] Read more.

The Early Pleistocene continental deposits of the Tiberino Basin (Central Italy) host exceptionally preserved fossil charophyte assemblages that provide critical insights into palaeoenvironmental and palaeoclimatic dynamics during a key phase of the Mediterranean evolution. Integrated micropalaeontological and sedimentological investigations at three reference sections reveal distinct charophyte communities characterized by Chara cf. hispida (Hartman) Wood, 1962, Chara cf. vulgaris Linnaeus, 1753, Nitellopsis obtusa (Desvaux in Loiseleur) Groves, 1919, and Lychnothamnus barbatus (Meyen, 1827) von Leonhardi 1863, not reported until now. These assemblages reflect a mosaic of stable lacustrine, ephemeral swamp, and palustrine environments shaped by increasing climatic oscillations approaching the Early–Middle Pleistocene transition. Comparative data from Mediterranean basins, such as Laguna de Gallocanta, Lake Afourgagh, and Ilgin Palaeolake (Türkiye), highlight the role of charophytes as sensitive indicators of hydrological and climatic variability. This study strengthens the palaeolimnological and palaeoenvironmental significance of charophyte fossils and proposes new avenues for multidisciplinary research into Quaternary environmental evolution in Mediterranean continental basins. Full article

(This article belongs to the Section Climate and Environment)

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22 pages, 4943 KB

Open AccessArticle

Novel Wall Reef Identification Method Using Landsat 8: A Case Study of Microcontinent Areas in Wangiwangi Island, Indonesia

by Wikanti Asriningrum, Azura Ulfa, Edy Trihatmoko, Nugraheni Setyaningrum, Joko Widodo, Ahmad Sutanto, Suwarsono, Gathot Winarso, Bachtiar Wahyu Mutaqin and Eko Siswanto

Geosciences 2025, 15(10), 391; https://doi.org/10.3390/geosciences15100391 - 10 Oct 2025

Viewed by 291

Abstract

This study develops a geomorphological identification methodology for wall reefs in the microcontinental environment of Wangiwangi Island, Indonesia, using medium-resolution Landsat 8 satellite imagery and morphological analysis based on Maxwell’s geomorphological framework. The uniqueness of the wall reef landform lies in the fact [...] Read more.

This study develops a geomorphological identification methodology for wall reefs in the microcontinental environment of Wangiwangi Island, Indonesia, using medium-resolution Landsat 8 satellite imagery and morphological analysis based on Maxwell’s geomorphological framework. The uniqueness of the wall reef landform lies in the fact that the lagoon elongates on limestone, resulting in a habitat and ecosystem that develops differently from those of other shelf reefs, namely, platform reefs and plug reefs. Using Optimum Index Factor (OIF) optimization and RGB image composites, four reef types were successfully identified: cuspate reefs, open ring reefs, closed ring reefs, and resorbed reefs. A field check was conducted at fifteen observation sites, which included measurements of depth, turbidity, and water quality parameters, as well as an in situ benthic habitat inventory. The analysis results showed a strong correlation between image composites, geomorphological reef classes, and ecological conditions, confirming the successful adaptation of Maxwell’s classification to the Indonesian reef system. This hybrid integrated approach successfully maps the distribution of reefs on a complex continental shelf, providing an essential database for shallow-water spatial planning, ecosystem-based conservation, and sustainable management in the Coral Triangle region. Policy recommendations include zoning schemes for protected areas based on reef landform morphology, strengthening integrative monitoring systems, and utilizing high-resolution imagery and machine learning algorithms in further research. Full article

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26 pages, 20862 KB

Open AccessArticle

GIS-Based Landslide Susceptibility Mapping with a Blended Ensemble Model and Key Influencing Factors in Sentani, Papua, Indonesia

by Zulfahmi Zulfahmi, Moch Hilmi Zaenal Putra, Dwi Sarah, Adrin Tohari, Nendaryono Madiutomo, Priyo Hartanto and Retno Damayanti

Geosciences 2025, 15(10), 390; https://doi.org/10.3390/geosciences15100390 - 9 Oct 2025

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Abstract

Landslides represent a recurrent hazard in tropical mountain environments, where rapid urbanization and extreme rainfall amplify disaster risk. The Sentani region of Papua, Indonesia, is highly vulnerable, as demonstrated by the catastrophic debris flows of March 2019 that caused fatalities and widespread losses. [...] Read more.

Landslides represent a recurrent hazard in tropical mountain environments, where rapid urbanization and extreme rainfall amplify disaster risk. The Sentani region of Papua, Indonesia, is highly vulnerable, as demonstrated by the catastrophic debris flows of March 2019 that caused fatalities and widespread losses. This study developed high-resolution landslide susceptibility maps for Sentani using an ensemble machine learning framework. Three base learners—Random Forest, eXtreme Gradient Boosting (XGBoost), and CatBoost—were combined through a logistic regression meta-learner. Predictor redundancy was controlled using Pearson correlation and Variance Inflation Factor/Tolerance (VIF/TOL). The landslide inventory was constructed from multitemporal satellite imagery, integrating geological, topographic, hydrological, environmental, and seismic factors. Results showed that lithology, Slope Length and Steepness Factor (LS Factor), and earthquake density consistently dominated model predictions. The ensemble achieved the most balanced predictive performance, Area Under the Curve (AUC) > 0.96, and generated susceptibility maps that aligned closely with observed landslide occurrences. SHapley Additive Explanations (SHAP) analyses provided transparent, case-specific insights into the directional influence of key factors. Collectively, the findings highlight both the robustness and interpretability of ensemble learning for landslide susceptibility mapping, offering actionable evidence to support disaster preparedness, land-use planning, and sustainable development in Papua. Full article

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25 pages, 1098 KB

Open AccessReview

Review of Nano- and Micro- Indentation Tests for Rocks

by Qingqing He and Heinz Konietzky

Geosciences 2025, 15(10), 389; https://doi.org/10.3390/geosciences15100389 - 7 Oct 2025

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Abstract

Nano- and micro-indentation have become essential tools for quantifying the micromechanical behavior of rocks beyond traditional macroscopic tests. This review summarizes the historical evolution, experimental methodologies, and interpretation models (e.g., Oliver–Pharr, Doerner–Nix, energy-based methods, Hertz/ECM/Lawn), with a particular focus on rock-specific challenges such [...] Read more.

Nano- and micro-indentation have become essential tools for quantifying the micromechanical behavior of rocks beyond traditional macroscopic tests. This review summarizes the historical evolution, experimental methodologies, and interpretation models (e.g., Oliver–Pharr, Doerner–Nix, energy-based methods, Hertz/ECM/Lawn), with a particular focus on rock-specific challenges such as heterogeneity, anisotropy, and surface roughness. A structured literature survey (1980–August 2025) covers representative studies on shale, limestone, marble, sandstone, claystone, and granite. The transition from classical hardness measurements to advanced instrumented indentation has enabled more reliable determination of localized properties, including hardness, elastic modulus, fracture toughness, and creep. Special attention is given to the applicability and limitations of different interpretation models when applied to heterogeneous and anisotropic rocks. Current challenges include high sensitivity to surface conditions and difficulties in capturing the full complexity of natural rock behavior. Looking forward, promising directions involve intelligent systems that integrate AI-driven data analytics, robotic automation, and multiscale modeling (from molecular dynamics to continuum FEM) to enable predictive material design. This review aims to provide geoscientists and engineers with a comprehensive foundation for the effective application and further development of indentation-based testing in rock mechanics and geotechnical engineering. Full article

(This article belongs to the Section Geomechanics)

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20 pages, 2824 KB

Open AccessArticle

Seven Decades of River Change: Sediment Dynamics in the Diable River, Quebec

by Ali Faghfouri, Daniel Germain and Guillaume Fortin

Geosciences 2025, 15(10), 388; https://doi.org/10.3390/geosciences15100388 - 4 Oct 2025

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Abstract

This study reconstructs seven decades (1949–2019) of morphodynamic changes and sediment dynamics in the Diable River (Québec, Canada) using nine series of aerial photographs, a high-resolution LiDAR Digital Elevation Model (2021), and grain-size analysis. The objectives were to document long-term river evolution, quantify [...] Read more.

This study reconstructs seven decades (1949–2019) of morphodynamic changes and sediment dynamics in the Diable River (Québec, Canada) using nine series of aerial photographs, a high-resolution LiDAR Digital Elevation Model (2021), and grain-size analysis. The objectives were to document long-term river evolution, quantify erosion and deposition, and evaluate sediment connectivity between eroding sandy bluffs and depositional zones. Planform analysis and sediment budgets derived from DEMs of Difference (DoD) reveal an oscillatory trajectory characterized by alternating phases of sediment export and temporary stabilization, rather than a simple trend of degradation or aggradation. The most dynamic interval (1980–2001) was marked by widespread meander migration and the largest net export (−142.5 m³/km/year), whereas the 2001–2007 interval showed net storage (+70.8 m³/km/year) and short-term geomorphic recovery. More recent floods (2017, 2019; 20–50-year return periods) induced localized but persistent sediment loss, underlining the structuring role of extreme events. Grain-size results indicate partial connectivity: coarse fractions tend to remain in local depositional features, while finer sediments are preferentially exported downstream. These findings emphasize the geomorphic value of temporary sediment sinks (bars, beaches) and highlight the need for adaptive river management strategies that integrate sediment budgets and local knowledge into floodplain governance. Full article

(This article belongs to the Special Issue Integrating Geomorphological and Hydrological Insights for Flood Risk Assessment)

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16 pages, 2720 KB

Open AccessArticle

Shale Oil T₂ Spectrum Inversion Method Based on Autoencoder and Fourier Transform

by Jun Zhao, Shixiang Jiao, Li Bai, Bing Xie, Yan Chen, Zhenguan Wu and Shaomin Zhang

Geosciences 2025, 15(10), 387; https://doi.org/10.3390/geosciences15100387 - 4 Oct 2025

Viewed by 316

Abstract

Accurate inversion of the T₂ spectrum of shale oil reservoir fluids is crucial for reservoir evaluation. However, traditional nuclear magnetic resonance inversion methods face challenges in extracting features from multi-exponential decay signals. This study proposed an inversion method that combines autoencoder (AE) [...] Read more.

Accurate inversion of the T₂ spectrum of shale oil reservoir fluids is crucial for reservoir evaluation. However, traditional nuclear magnetic resonance inversion methods face challenges in extracting features from multi-exponential decay signals. This study proposed an inversion method that combines autoencoder (AE) and Fourier transform, aiming to enhance the accuracy and stability of T₂ spectrum estimation for shale oil reservoirs. The autoencoder is employed to automatically extract deep features from the echo train, while the Fourier transform is used to enhance frequency domain features of multi-exponential decay information. Furthermore, this paper designs a customized weighted loss function based on a self-attention mechanism to focus the model’s learning capability on peak regions, thereby mitigating the negative impact of zero-value regions on model training. Experimental results demonstrate significant improvements in inversion accuracy, noise resistance, and computational efficiency compared to traditional inversion methods. This research provides an efficient and reliable new approach for precise evaluation of the T₂ spectrum in shale oil reservoirs. Full article

(This article belongs to the Section Geophysics)

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19 pages, 6432 KB

Open AccessArticle

Storage and Production Aspects of Reservoir Fluids in Sedimentary Core Rocks

by Jumana Sharanik, Ernestos Sarris and Constantinos Hadjistassou

Geosciences 2025, 15(10), 386; https://doi.org/10.3390/geosciences15100386 - 3 Oct 2025

Viewed by 345

Abstract

Understanding the fluid storage and production mechanisms in sedimentary rocks is vital for optimising natural gas extraction and subsurface resource management. This study applies high-resolution X-ray computed tomography (≈15 μm) to digitise rock samples from onshore Cyprus, producing digital rock models from DICOM [...] Read more.

Understanding the fluid storage and production mechanisms in sedimentary rocks is vital for optimising natural gas extraction and subsurface resource management. This study applies high-resolution X-ray computed tomography (≈15 μm) to digitise rock samples from onshore Cyprus, producing digital rock models from DICOM images. The workflow, including digitisation, numerical simulation of natural gas flow, and experimental validation, demonstrates strong agreement between digital and laboratory-measured porosity, confirming the methods’ reliability. Synthetic sand packs generated via particle-based modelling provide further insight into the gas storage mechanisms. A linear porosity–permeability relationship was observed, with porosity increasing from 0 to 35% and permeability from 0 to 3.34 mD. Permeability proved critical for production, as a rise from 1.5 to 3 mD nearly doubled the gas flow rate (14 to 30 fm³/s). Grain morphology also influenced gas storage. Increasing roundness enhanced porosity from 0.30 to 0.41, boosting stored gas volume by 47.6% to 42 fm³. Although based on Cyprus retrieved samples, the methodology is applicable to sedimentary formations elsewhere. The findings have implications for enhanced oil recovery, CO₂ sequestration, hydrogen storage, and groundwater extraction. This work highlights digital rock physics as a scalable technology for investigating transport behaviour in porous media and improving characterisation of complex sedimentary reservoirs. Full article

(This article belongs to the Special Issue Advancements in Geological Fluid Flow and Mechanical Properties)

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22 pages, 8701 KB

Open AccessArticle

A Web-GIS Platform for Real-Time Scenario-Based Seismic Risk Assessment at National Level

by Agostino Goretti, Marta Faravelli, Chiara Casarotti, Barbara Borzi and Davide Quaroni

Geosciences 2025, 15(10), 385; https://doi.org/10.3390/geosciences15100385 - 3 Oct 2025

Viewed by 363

Abstract

The paper presents the main features of a Web-GIS platform designed to compute real-time scenario-based seismic risk assessments at the national level. Based on the Italian experience, the platform enables DRM scientist and policymakers to readily generate seismic scenarios supporting the entire DRM [...] Read more.

The paper presents the main features of a Web-GIS platform designed to compute real-time scenario-based seismic risk assessments at the national level. Based on the Italian experience, the platform enables DRM scientist and policymakers to readily generate seismic scenarios supporting the entire DRM cycle, including training, emergency planning, calibrating operations during response, and providing seismic risk estimates for National Disaster Risk Assessment or seismic risk reduction programs. The platform is immediately operational, relying on preloaded freeware datasets on exposure and vulnerability, and requiring only basic earthquake parameters to perform real-time analysis. At a later stage, these datasets should be replaced with more detailed and accurate national-level data. The platform generates earthquake impact assessments that include physical damage, economic and human losses, and key emergency response indicators, such as estimated displaced population, required tent camps, and EMT and USAR needs. Its key innovation lies in the ability to operate at the national scale, offering immediate usability with the possibility of further customization. As a web-based service with a user-friendly graphical interface, it is particularly suited for civil protection and DRM experts. Full article

(This article belongs to the Special Issue Advancing Earthquake Forecasting: Integrating Physics-Based and Statistical Approaches)

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18 pages, 19543 KB

Open AccessArticle

Detrital Zircon U-Pb Age Data and Geochemistry of Clastic Rocks in the Xiahe–Hezuo Area: Implications for the Late Paleozoic–Mesozoic Tectonic Evolution of the West Qinling Orogen

by Hang Li, Kang Yan, Kangning Li, Ke Yang, Baocheng Fan, Zhongkai Xue, Li Chen and Haomin Guo

Geosciences 2025, 15(10), 384; https://doi.org/10.3390/geosciences15100384 - 3 Oct 2025

Viewed by 342

Abstract

The West Qinling Orogenic Belt (WQOB) contains a sedimentary succession that is approximately 15 km thick, spanning from the Carboniferous to the Jurassic period. This succession offers critical insights into the tectonic evolution of the Paleo-Tethys Ocean. While previous models have suggested various [...] Read more.

The West Qinling Orogenic Belt (WQOB) contains a sedimentary succession that is approximately 15 km thick, spanning from the Carboniferous to the Jurassic period. This succession offers critical insights into the tectonic evolution of the Paleo-Tethys Ocean. While previous models have suggested various depositional environments, the late Paleozoic to Mesozoic tectonic evolution of the WQOB is still not fully understood. In this study, we incorporate new detrital zircon U-Pb age data and whole-rock geochemical analyses from six stratigraphic units, dating back to the Carboniferous to Triassic periods in the Xiahe–Hezuo region, alongside existing datasets. The detrital zircon age spectra from the WQOB reveal three distinct groups: Devonian–Carboniferous strata exhibit dominant Neoproterozoic (~800–900 Ma) zircon populations, whereas Permian–Triassic rock samples show prominent Paleoproterozoic (1840–1880 Ma) and Archean (2450–2500 Ma) peaks. A minor Neoproterozoic component in Permian spectra disappears by the Triassic, while Jurassic–Cretaceous assemblages lack Precambrian grains. These trends reflect evolving source terranes linked to Paleo-Tethyan subduction dynamics. Furthermore, the geochemical signatures of the Devonian–Triassic clastic rocks align with the composition of upper continental crust, indicating a tectonic relationship with continental island arcs and active continental margins. By synthesizing these findings with established detrital zircon ages, magmatic records, and geophysical data, we propose that the WQOB underwent pre-Triassic tectonic evolution that was marked by pre-Triassic subduction and localized extension during the process of continental underthrusting. Full article

(This article belongs to the Special Issue Detrital Minerals Geochronology and Sedimentary Provenance)

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42 pages, 45904 KB

Open AccessArticle

Sedimentary Architecture Prediction Using Facies Interpretation and Forward Seismic Modeling: Application to a Mediterranean Land–Sea Pliocene Infill (Roussillon Basin, France)

by Teddy Widemann, Eric Lasseur, Johanna Lofi, Serge Berné, Carine Grélaud, Benoît Issautier, Philippe-A. Pezard and Yvan Caballero

Geosciences 2025, 15(10), 383; https://doi.org/10.3390/geosciences15100383 - 3 Oct 2025

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Abstract

This study predicts sedimentary architectures and facies distribution within the Pliocene prograding prism of the Roussillon Basin (Gulf of Lion, France), developed along an onshore–offshore continuum. Boreholes and outcrops provide facies-scale observations onshore, while seismic data capture basin-scale structures offshore. Forward seismic modeling [...] Read more.

This study predicts sedimentary architectures and facies distribution within the Pliocene prograding prism of the Roussillon Basin (Gulf of Lion, France), developed along an onshore–offshore continuum. Boreholes and outcrops provide facies-scale observations onshore, while seismic data capture basin-scale structures offshore. Forward seismic modeling bridges spatial and scale gaps between these datasets, yielding characteristic synthetic seismic signatures for the sedimentary facies associations observed onshore, used as analogs for offshore deposits. These signatures are then identified in offshore seismic data, allowing seismic profiles to be populated with sedimentary facies without a well tie. Predicted offshore architectures are consistent with shoreline trajectories and facies successions observed onshore. The Roussillon prism records passive margin reconstruction in the Mediterranean Basin following the Messinian Salinity Crisis, through the following three successive depositional profiles marking the onset of infilling: (1) Gilbert deltas, (2) wave- and storm-reworked fan deltas, and (3) a wave-dominated delta. Offshore, transitions in clinoform type modify sedimentary architectures, influenced by inherited Messinian paleotopography. This autogenic control generates spatial variability in accommodation, driving changes in depositional style. Overall, this multi-scale and integrative approach provides a robust framework for predicting offshore sedimentary architectures and can be applied to other deltaic settings with limited land–sea data continuity. Full article

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18 pages, 3371 KB

Open AccessArticle

Fusing Geoscience Large Language Models and Lightweight RAG for Enhanced Geological Question Answering

by Bo Zhou and Ke Li

Geosciences 2025, 15(10), 382; https://doi.org/10.3390/geosciences15100382 - 2 Oct 2025

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Abstract

Mineral prospecting from vast geological text corpora is impeded by challenges in domain-specific semantic interpretation and knowledge synthesis. General-purpose Large Language Models (LLMs) struggle to parse the complex lexicon and relational semantics of geological texts, limiting their utility for constructing precise knowledge graphs [...] Read more.

Mineral prospecting from vast geological text corpora is impeded by challenges in domain-specific semantic interpretation and knowledge synthesis. General-purpose Large Language Models (LLMs) struggle to parse the complex lexicon and relational semantics of geological texts, limiting their utility for constructing precise knowledge graphs (KGs). Our novel framework addresses this gap by integrating a domain-specific LLM, GeoGPT, with a lightweight retrieval-augmented generation architecture, LightRAG. Within this framework, GeoGPT automates the construction of a high-quality mineral-prospecting KG by performing ontology definition, entity recognition, and relation extraction. The LightRAG component then leverages this KG to power a specialized geological question-answering (Q&A) system featuring a dual-layer retrieval mechanism for enhanced precision and an incremental update capability for dynamic knowledge incorporation. The results indicate that the proposed method achieves a mean F1-score of 0.835 for entity extraction, representing a 17% to 25% performance improvement over general-purpose large models using generic prompts. Furthermore, the geological Q&A model, built upon the LightRAG framework with GeoGPT as its core, demonstrates a superior win rate against the DeepSeek-V3 and Qwen2.5-72B general-purpose large models by 8–29% in the geochemistry domain and 53–78% in the remote sensing geology domain. This study establishes an effective and scalable methodology for intelligent geological text analysis, enabling lightweight, high-performance Q&A systems that accelerate knowledge discovery in mineral exploration. Full article

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22 pages, 12373 KB

Open AccessArticle

Groundwater Quality and Health Risk Assessment in Trenggalek Karst Springs and Underground Rivers as a Drinking Water Source

by Aminuddin, Nendaryono Madiutomo, Zulfahmi, Tedy Agung Cahyadi, Ilham Firmansyah, Rizka Maria, Heri Nurohman and Nopri Dwi Siswanto

Geosciences 2025, 15(10), 381; https://doi.org/10.3390/geosciences15100381 - 2 Oct 2025

Viewed by 431

Abstract

The karst landscape of Trenggalek Regency, located in several sub-districts including Dongko, Kampak, and Watulimo, is shaped by the Wonosari Formation and is characterized by springs and underground rivers. Due to water scarcity in the region, local communities heavily depend on these natural [...] Read more.

The karst landscape of Trenggalek Regency, located in several sub-districts including Dongko, Kampak, and Watulimo, is shaped by the Wonosari Formation and is characterized by springs and underground rivers. Due to water scarcity in the region, local communities heavily depend on these natural water sources. This study assesses the groundwater quality of 16 springs and 20 underground rivers to evaluate their suitability for consumption and associated health risks. Using the groundwater quality index (GWQI), human health risk assessment (HHRA), and statistical methods, various physicochemical parameters were analyzed, including pH, total dissolved solids (TDS), electrical conductivity (EC), and concentrations of iron (Fe²⁺), manganese (Mn²⁺), calcium carbonate (CaCO₃), and sulfate (SO₄). Water generally meets the World Health Organization standards for safe drinking. However, correlation analysis reveals notable mineral dissolution and possible anthropogenic influence. TDS strongly correlates with EC (r = 0.97), while Fe²⁺ shows significant relationships with Mn and TDS. Conversely, CaCO₃ shows a negative correlation with EC and TDS, suggesting alternative sources beyond rock weathering. The HHRA indicates higher non-carcinogenic health risks from Fe²⁺ contamination in underground rivers compared to springs. The study’s novelty comes in its integrated assessment of groundwater quality and health hazards in Trenggalek’s karst region, which uses GWQI, HHRA, and statistical analysis to show geochemical interactions and highlight iron-related health issues in underground rivers. Full article

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41 pages, 65993 KB

Open AccessArticle

Spatial Distribution of Geochemical Anomalies in Soils of River Basins of the Northeastern Caucasus

by Ekaterina Kashirina, Roman Gorbunov, Ibragim Kerimov, Tatiana Gorbunova, Polina Drygval, Ekaterina Chuprina, Aleksandra Nikiforova, Nastasia Lineva, Anna Drygval, Andrey Kelip, Cam Nhung Pham and Nikolai Bratanov

Geosciences 2025, 15(10), 380; https://doi.org/10.3390/geosciences15100380 - 1 Oct 2025

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Abstract

The aim of this study is to determine the spatial distribution of geochemical anomalies of selected potential toxic elements in the soils of the river basins in the Northeastern Caucasus—specifically the Ulluchay, Sulak, and Sunzha Rivers. A concentration of 25 chemical elements was [...] Read more.

The aim of this study is to determine the spatial distribution of geochemical anomalies of selected potential toxic elements in the soils of the river basins in the Northeastern Caucasus—specifically the Ulluchay, Sulak, and Sunzha Rivers. A concentration of 25 chemical elements was measured using inductively coupled plasma mass spectrometry (ICP-MS). Petrogenic elements commonly found in the Earth’s crust (Al, Na, Ca, Fe, Mg) showed high concentrations (Na up to 306,600.70 mg/kg). Conversely, concentrations of Ag, Cd, Sn, Sb, and Te at many sampling sites were extremely low, falling below the detection limits of analytical instruments. The geochemical indicators Cf (contamination factor) and Igeo (geoaccumulation index) indicate that the regional characteristics of the territory, such as lithological conditions, hydrochemical schedules, and the history of geological development of the territory, affect the concentration of elements. Anomalous concentrations were found for seven elements (Ba, Na, Zn, Ag, Li, Sc, As), whereas no anomalies were identified for Be, Mg, Al, Mn, Fe, Co, Ni, Cu, Pb, Te, and Cs. For the most part (8 of 10), the sampling sites with anomalous chemical element content are located in the basin of the Sunzha River. Two sites with anomalous chemical element content have been identified in the Sulak River Basin. Anomalous values in the Sulak River Basin are noted for two chemical elements—Ba and Na. Natural features such as geological structure, parent rock composition, vertical climatic zonation, and landscape diversity play a major role in forming geochemical anomalies. The role of anthropogenic factors increases in localized areas near settlements, industrial facilities, and roads. The spatial distribution of geochemical anomalies must be considered in agricultural management, the use of water sources for drinking supply, the development of tourist routes, and comprehensive spatial planning. Full article

(This article belongs to the Special Issue Soil Geochemistry)

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23 pages, 3989 KB

Open AccessArticle

Sequence Stratigraphy of the Volhynian (Late Middle Miocene) Deposits from the North Sector of Eastern Carpathian Foredeep

by Crina Miclӑuș, Anca Seserman, Sergiu Loghin and Viorel Ionesi

Geosciences 2025, 15(10), 379; https://doi.org/10.3390/geosciences15100379 - 1 Oct 2025

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Abstract

An exposed sedimentary succession, ca 115 m of a total of 1000 m, from the Eastern Carpathian foredeep was, for the first time, analyzed using facies analysis and scale- and time-independent sequence stratigraphy methods to reveal the depositional environment and its cyclic sedimentation. [...] Read more.

An exposed sedimentary succession, ca 115 m of a total of 1000 m, from the Eastern Carpathian foredeep was, for the first time, analyzed using facies analysis and scale- and time-independent sequence stratigraphy methods to reveal the depositional environment and its cyclic sedimentation. The outcropping deposits, belonging to the Șomuz Formation, dated on the basis of molluscs, foraminifera, and ostracods, are uppermost Volhynian (upper Serravalian). The three recurrent facies associations we have distinguished indicate a storm-dominated shoreface–offshore transition environment. Five-decametre-thick high-frequency sequences (HFS1–5), at most of 4th order, bounded by maximum regressive surfaces, were defined in the studied interval. The maximum thickness of the Volhynian deposits in the area, known both from well sites and outcrops, allowed us to estimate the sedimentation rate at ca 1.5 m/kyr. The fossil content shows that the entire sedimentary succession was deposited in very shallow to shallow water during the whole Volhynian (12.65 - ca 12.01 Ma). The time interval we studied was estimated at ca 75 kyr, so the average time of one HFS is ca 15 kyr. At this scale, considering that both high subsidence and Eastern Paratethys sea-level rise added to accommodation, the sediment supply must have been the main control of cyclic sedimentation, which, in turn, must have been controlled by precession climatic changes in the source area. The estimated time of an HFS is shorter than a precession cycle, but better dating might support or refute this hypothesis. This paper may awaken the interest of the owners of better data, especially from subsurface (seismic, well logs), to complete the data from natural exposures. Full article

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

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32 pages, 3829 KB

Open AccessArticle

Summary Results of Radon-222 Activity Monitoring in Karst Caves in Bulgaria

by Petar Stefanov, Karel Turek and Ludmil Tsankov

Geosciences 2025, 15(10), 378; https://doi.org/10.3390/geosciences15100378 - 1 Oct 2025

Viewed by 367

Abstract

Cave systems are a kind of natural laboratory for interdisciplinary research on karstogenesis in the context of global changes. In this study, we investigate the concentration of ²²²Rn at 65 points in 37 representative caves of Bulgarian karst through continuous monitoring with [...] Read more.

Cave systems are a kind of natural laboratory for interdisciplinary research on karstogenesis in the context of global changes. In this study, we investigate the concentration of ²²²Rn at 65 points in 37 representative caves of Bulgarian karst through continuous monitoring with passive and active detectors with a duration of 1 to 13 years. The concentration changes strongly both in the long term and seasonally, with values from 0.1 to 13 kBq m⁻³. These variations are analyzed from different perspectives (location and morphological features of the cave system, cave climate, ventilation regime, etc.). The seasonal change in the direction and intensity of ventilation is a leading factor determining the gas composition of the cave atmosphere during the year. Parallel measurements of ²²²Rn and CO₂ concentrations in the cave air show that both gases have a similar seasonal fluctuation. Cases of coincidences of an anomalous increase in the concentration of ²²²Rn with manifestations of seismic activity and micro-displacements along tectonic cracks in the caves have also been registered. The dependencies between the ²²²Rn concentration in the caves and in the soil above them are also discussed, as well as the possible connections between global trends in climate change and trends in ²²²Rn emissions. Special attention is paid to the risks of radiation exposure in show caves. A calculation procedure has been developed to achieve the realistic assessment of the effective dose of cave guides. It is based on information about the annual course of the ²²²Rn concentration in the respective cave and the time schedule of the guides’ stay in it. The calculation showed that the effective dose may exceed the permitted limits, and it is thus necessary to control it. Full article

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15 pages, 14032 KB

Open AccessArticle

Preliminary Study on the Activity of the Rupture Zone in the Eastern Segment of the Ba Co Fault in Ngari Prefecture, Tibet

by Yunsheng Yao, Yanxiu Shao and Bo Zhang

Geosciences 2025, 15(10), 377; https://doi.org/10.3390/geosciences15100377 - 1 Oct 2025

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Abstract

The lack of research on the slip behavior of the NW-trending faults in the central Tibetan Plateau constrains our understanding of the deformation models for this region. The Ba Co Fault, located in the central Tibetan Plateau, is a NW–SE-trending right-lateral strike-slip fault. [...] Read more.

The lack of research on the slip behavior of the NW-trending faults in the central Tibetan Plateau constrains our understanding of the deformation models for this region. The Ba Co Fault, located in the central Tibetan Plateau, is a NW–SE-trending right-lateral strike-slip fault. Its eastern section has been active in the Holocene and plays an important accommodating role in the northward compression and east–west extension of the Tibetan Plateau. This study presents a detailed analysis of the geomorphic features of the eastern section of the Ba Co Fault in the Ngari Prefecture of Tibet, precisely measuring the newly discovered surface rupture zone on its eastern side and preliminarily discussing the activity of the fault based on the optically stimulated luminescence (OSL) dating results. The results reveal that the eastern segment of the Ba Co Fault displays geomorphic evidence of offset, including displaced Holocene alluvial–fluvial fans at the mountain front and partially offset ridges. A series of pressure ridges, trenches, counter-slope scarps, and shutter ridge ponds have developed along the fault trace. Some gullies exhibit a cumulative dextral displacement of approximately 16–52 m. The newly discovered co-seismic surface rupture zone extends for a total length of ~21 km, with a width ranging from 30 to 102 m. Pressure ridges within the rupture zone reach heights of 0.3–5.5 m, while trenches exhibit depths of 0.6–15 m. Optically stimulated luminescence (OSL) dating constrains the timing of the surface-rupturing earthquake to after 5.73 ± 0.17 ka. The eastern segment of the Ba Co Fault experienced a NW-trending compressional deformation regime during the Holocene, manifesting as a transpressional dextral strike-slip fault. Magnitude estimation indicates that this segment possesses the potential to generate earthquakes of M ≥ 6. The regional tectonic analysis indicates that the activity of the eastern section of the Ba Co Fault is related to the shear model of the conjugate strike-slip fault zone in the central Tibetan Plateau and may play a boundary role between different shear zones. Full article

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