Pub Date : 2025-07-12DOI: 10.1016/j.geogeo.2025.100431
Lívia Leskóné Majoros , Máté Zs. Leskó , Krisztián Fintor , Ferenc Móricz , Délia Bulátkó-Debus , Sándor Szakáll , Ferenc Kristály
The metamorphic temperature of rock bodies can be estimated from the degree of graphitization of carbonaceous material, best determined by Raman spectroscopy. Graphite-bearing rocks from intensely folded black phyllites (black schists) near Meszes village in the Szendrő Mts., NE-Hungary, were analyzed using ore microscopy, scanning electron microscopy (SEM-EDX), X-ray powder diffraction (XRD), Raman spectroscopy and X-ray fluorescence spectrometry (XRF). The exposed Szendrő Phyllite Formation is of Carboniferous age, represents a gradually deepening basin fill, metamorphosed under greenschist facies conditions. Due to its low quantity and the presence of significant muscovite (± illite) 2M1, clinochlore and quartz content, graphite is not directly detectable by XRD. Graphite occurs as intensely deformed 50–150 μm sized flakes persistently with kink-band microstructure and undulose extinction. The absence of S and Cl (confirmed by EDX) indicates a total maturation of the carbonaceous material into pure, disordered graphite with higher crystal ordering supported also by the initial splitting of S2 Raman band. The average formation temperature is estimated at 425°C (±50°C) by the Beyssac-method and 417°C (±50°C) by the Aoya-method.
{"title":"Accessory graphite in phyllites as indicator of metamorphic grade and stage (Szendrő Mts., NE Hungary)","authors":"Lívia Leskóné Majoros , Máté Zs. Leskó , Krisztián Fintor , Ferenc Móricz , Délia Bulátkó-Debus , Sándor Szakáll , Ferenc Kristály","doi":"10.1016/j.geogeo.2025.100431","DOIUrl":"10.1016/j.geogeo.2025.100431","url":null,"abstract":"<div><div>The metamorphic temperature of rock bodies can be estimated from the degree of graphitization of carbonaceous material, best determined by Raman spectroscopy. Graphite-bearing rocks from intensely folded black phyllites (black schists) near Meszes village in the Szendrő Mts., NE-Hungary, were analyzed using ore microscopy, scanning electron microscopy (SEM-EDX), X-ray powder diffraction (XRD), Raman spectroscopy and X-ray fluorescence spectrometry (XRF). The exposed Szendrő Phyllite Formation is of Carboniferous age, represents a gradually deepening basin fill, metamorphosed under greenschist facies conditions. Due to its low quantity and the presence of significant muscovite (± illite) 2M<sub>1</sub>, clinochlore and quartz content, graphite is not directly detectable by XRD. Graphite occurs as intensely deformed 50–150 μm sized flakes persistently with kink-band microstructure and undulose extinction. The absence of S and Cl (confirmed by EDX) indicates a total maturation of the carbonaceous material into pure, disordered graphite with higher crystal ordering supported also by the initial splitting of S2 Raman band. The average formation temperature is estimated at 425°C (±50°C) by the Beyssac-method and 417°C (±50°C) by the Aoya-method.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100431"},"PeriodicalIF":0.0,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Drought is the outcome of unequal rainfall distribution over time and space which negatively impacts agricultural productivity and social well-being. Analyzing the spatiotemporal drought variability in terms of intensity and magnitude is necessary for improving agricultural productivity. The main goal of the study is to analyze the long-term rainfall trend and measure the frequency and severity of droughts in 10 Agro-Climatic Zones (ACZs) of Odisha, India from 1988 to 2022. Secondary data sources, like rainfall data of Special Relief Commissioner (SRC), Standardized Precipitation-Evapotranspiration Index (SPEI) database, Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) data and GLDAS-2.2: Global Land Data Assimilation System data are used to achieve the objective. Moreover, field data is collected to validate drought scenario. In this study, Innovative Trend Analysis (ITA) is used to evaluate rainfall trends. Drought scenario mapping is done through Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI) method and various drought indices like Vegetation Condition Index (VCI), Temperature Condition Index (TCI), Precipitation Condition Index (PCI), and Integrated Drought Severity Index (IDSI). The study found highly increasing trend in rainfall in 2006–2022 compared to 1989–2005, over Eastern Ghat High Land (EGHL), Northwestern Plateau (NWP), North Central Plateau (NCP), and Northeastern Ghat (NEG). While moderately decreasing trend observed over Northeastern Coastal Plain (NECP) and Eastern and Southeastern Coastal Plain (ESECP). High drought frequency with extreme severity noticed over NECP, and severe over Western Undulating Zone (WUZ) and Western Central Table Land (WCTL). Low IDSI values reflecting severe drought effects which noticed over WCTL, WUZ and Mid Central Table Land (MCTL) in 2016, WCTL and ESECP in 2018 and MCTL, ESECP, and NCP in 2022. The study provides critical insights to the current scenario of knowledge of drought condition for better understanding the drought and agricultural planning in each ACZ of Odisha.
干旱是降雨随时间和空间分布不均的结果，对农业生产力和社会福祉产生负面影响。分析干旱时空变化的强度和幅度，是提高农业生产力的必要条件。该研究的主要目标是分析1988年至2022年印度奥里萨邦10个农业气气带（acz）的长期降雨趋势，并测量干旱的频率和严重程度。次要数据源包括美国特别救援专员（SRC）降雨数据、标准化降水-蒸散发指数（SPEI）数据库、Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor （TIRS）数据以及GLDAS-2.2: Global Land data Assimilation System数据。此外，还收集了现场数据来验证干旱情景。本研究采用创新趋势分析（ITA）来评估降雨趋势。通过标准化降水指数（SPI）、标准化降水蒸散指数（SPEI）方法和植被条件指数（VCI）、温度条件指数（TCI）、降水条件指数（PCI）、综合干旱严重程度指数（IDSI）等多种干旱指数完成干旱情景制图。研究发现，与1989-2005年相比，2006-2022年东高止高原（EGHL）、西北高原（NWP）、中北部高原（NCP）和东北高止高原（NEG）的降雨量呈高度增加趋势。东北沿海平原（NECP）和东、东南沿海平原（ESECP）呈中等下降趋势。东北东北地区干旱频次高，旱情严重，西部起伏带和中西部台地旱情严重。低IDSI值反映了2016年WCTL、WUZ和中部高原（MCTL）、2018年WCTL和ESECP以及2022年MCTL、ESECP和NCP的严重干旱效应。该研究为了解奥里萨邦每个ACZ的干旱和农业规划提供了重要的见解。
{"title":"Spatiotemporal rainfall trend analysis and drought identification in agro-climatic zones of Odisha, Eastern India","authors":"Laxmikanta Rana , Siba Sankar Sahu , Bubun Mahata , Mukul Maity , Simanchal Nayak","doi":"10.1016/j.geogeo.2025.100430","DOIUrl":"10.1016/j.geogeo.2025.100430","url":null,"abstract":"<div><div>Drought is the outcome of unequal rainfall distribution over time and space which negatively impacts agricultural productivity and social well-being. Analyzing the spatiotemporal drought variability in terms of intensity and magnitude is necessary for improving agricultural productivity. The main goal of the study is to analyze the long-term rainfall trend and measure the frequency and severity of droughts in 10 Agro-Climatic Zones (ACZs) of Odisha, India from 1988 to 2022. Secondary data sources, like rainfall data of Special Relief Commissioner (SRC), Standardized Precipitation-Evapotranspiration Index (SPEI) database, Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) data and GLDAS-2.2: Global Land Data Assimilation System data are used to achieve the objective. Moreover, field data is collected to validate drought scenario. In this study, Innovative Trend Analysis (ITA) is used to evaluate rainfall trends. Drought scenario mapping is done through Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI) method and various drought indices like Vegetation Condition Index (VCI), Temperature Condition Index (TCI), Precipitation Condition Index (PCI), and Integrated Drought Severity Index (IDSI). The study found highly increasing trend in rainfall in 2006–2022 compared to 1989–2005, over Eastern Ghat High Land (EGHL), Northwestern Plateau (NWP), North Central Plateau (NCP), and Northeastern Ghat (NEG). While moderately decreasing trend observed over Northeastern Coastal Plain (NECP) and Eastern and Southeastern Coastal Plain (ESECP). High drought frequency with extreme severity noticed over NECP, and severe over Western Undulating Zone (WUZ) and Western Central Table Land (WCTL). Low IDSI values reflecting severe drought effects which noticed over WCTL, WUZ and Mid Central Table Land (MCTL) in 2016, WCTL and ESECP in 2018 and MCTL, ESECP, and NCP in 2022. The study provides critical insights to the current scenario of knowledge of drought condition for better understanding the drought and agricultural planning in each ACZ of Odisha.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100430"},"PeriodicalIF":0.0,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144703997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The pore and grain size of rocks and geomaterials are very crucial factors in evaluating their usefulness in industrial productions, geological and petrophysical assessments, geotechnical engineering projects and environmental studies. The study techniques include low field NMR measurements via CPMG pulse sequence on fully saturated disc-shaped samples and grain size analysis on sample fragments. NMR Relaxation curves were inverted via conventional regularized least-squares inversion routine to generate pore size distribution (PSD). Grain size analysis using sieve method was based on grain size distribution (GSD) and statistical parameters (mean (Mz), sorting (σi), skewness (SKi), and kurtosis (KG)). PSD depicts the presence of micropore and mesopores in all samples, with macropores detected only in limestone. All samples manifest well connected multiple peak pore systems. Sandstone and glauconite samples exhibit bimodal PSD. PSD for Limestone samples is trimodal which is a manifestation of a more complex pore system common in carbonate rocks mainly due to the composition of grains, matrix and cement. Mz values reveal more of medium/coarse grain composition across samples, implying an intermediate to high energy depositional environment. σi values indicate poor to medium sorting which reveals that the rock sediments were likely deposited in fluvial-continental environments. KG values are a mix of mesokurtic, leptokurtic and platykurtic, indicating a combination of depositional environments. Observed spread in skewness values also corroborates the diverse nature of sediment transport for rock formation and existence of mixed or transitional environment.
{"title":"Integrated pore size and grain size characterization of geomaterials from Ewekoro, Eastern Dahomey Basin","authors":"Olawale Babatunde Olatinsu , Mathew Osaretin Ogieva , Kehinde Saheed Ishola , Amidu Abiola Ige-Adeyeye","doi":"10.1016/j.geogeo.2025.100428","DOIUrl":"10.1016/j.geogeo.2025.100428","url":null,"abstract":"<div><div>The pore and grain size of rocks and geomaterials are very crucial factors in evaluating their usefulness in industrial productions, geological and petrophysical assessments, geotechnical engineering projects and environmental studies. The study techniques include low field NMR measurements via CPMG pulse sequence on fully saturated disc-shaped samples and grain size analysis on sample fragments. NMR Relaxation curves were inverted via conventional regularized least-squares inversion routine to generate pore size distribution (PSD). Grain size analysis using sieve method was based on grain size distribution (GSD) and statistical parameters (mean (<em>Mz</em>), sorting (<em>σ</em><sub>i</sub>), skewness (<em>SK<sub>i</sub></em>), and kurtosis (<em>K<sub>G</sub></em>)). PSD depicts the presence of micropore and mesopores in all samples, with macropores detected only in limestone. All samples manifest well connected multiple peak pore systems. Sandstone and glauconite samples exhibit bimodal PSD. PSD for Limestone samples is trimodal which is a manifestation of a more complex pore system common in carbonate rocks mainly due to the composition of grains, matrix and cement. <em>M</em><sub>z</sub> values reveal more of medium/coarse grain composition across samples, implying an intermediate to high energy depositional environment. <em>σ</em><sub>i</sub> values indicate poor to medium sorting which reveals that the rock sediments were likely deposited in fluvial-continental environments. <em>K<sub>G</sub></em> values are a mix of mesokurtic, leptokurtic and platykurtic, indicating a combination of depositional environments. Observed spread in skewness values also corroborates the diverse nature of sediment transport for rock formation and existence of mixed or transitional environment.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100428"},"PeriodicalIF":0.0,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Bikélélé greenstone belt belongs to the Chaillu Massif, which corresponds to the northwestern part of the Congo Craton outcropping in the southwestern Republic of the Congo. It mainly consists of metavolcanic lithological sequences composed of amphibolites, clinopyroxene amphibolites, epidote amphibolites, amphibole gneisses and amphibole-chlorite schists. These rocks show granoblastic to grano-nematoblastic textures, and contain amphibole, plagioclase, alkali feldspar, quartz, chlorite, clinopyroxene, biotite, sericite, sphene and opaque minerals. They have high contents in SiO2, Fe2O3, Al2O3, CaO and MgO, with subordinate Na2O and K2O. In the REE chondrite-normalised diagrams, the metavolcanic rocks show flat to LREE-enriched and flat HREE patterns. However, in the primitive mantle-normalised diagrams, most of the samples show depletion in Nb, Ta and Ti. Trace and rare earth element (REE) data suggest that their protoliths correspond to basalts and basaltic andesites of tholeiitic and calc-alkaline affinity. The metavolcanic rocks likely formed by 2.5–4 % partial melting of a subcontinental lithospheric mantle source that was enriched through metasomatism involving sediment-derived melts and subduction-related fluids. The results of this study suggest that the protoliths of the Bikélélé metavolcanic rocks were emplaced in a subduction-related back-arc environment, during the second magmatic episode recorded in the Chaillu Massif and underwent metamorphic grade up to amphibolite facies during the Neoarchean tectono-metamorphic event.
{"title":"Geochemistry of the metavolcanic rocks from the Archean Bikélélé greenstone belt (Chaillu Massif, Republic of the Congo): Petrogenesis and tectonic implications","authors":"Yarsé Brodivier Mavoungou , Noël Watha-Ndoudy , Hardy Medry Dieu-Veill Nkodia , Anthony Temidayo Bolarinwa , Aliyu Ohiani Umaru , Georges Muhindo Kasay","doi":"10.1016/j.geogeo.2025.100429","DOIUrl":"10.1016/j.geogeo.2025.100429","url":null,"abstract":"<div><div>The Bikélélé greenstone belt belongs to the Chaillu Massif, which corresponds to the northwestern part of the Congo Craton outcropping in the southwestern Republic of the Congo. It mainly consists of metavolcanic lithological sequences composed of amphibolites, clinopyroxene amphibolites, epidote amphibolites, amphibole gneisses and amphibole-chlorite schists. These rocks show granoblastic to grano-nematoblastic textures, and contain amphibole, plagioclase, alkali feldspar, quartz, chlorite, clinopyroxene, biotite, sericite, sphene and opaque minerals. They have high contents in SiO<sub>2</sub>, Fe<sub>2</sub>O<sub>3</sub>, Al<sub>2</sub>O<sub>3</sub>, CaO and MgO, with subordinate Na<sub>2</sub>O and K<sub>2</sub>O. In the REE chondrite-normalised diagrams, the metavolcanic rocks show flat to LREE-enriched and flat HREE patterns. However, in the primitive mantle-normalised diagrams, most of the samples show depletion in Nb, Ta and Ti. Trace and rare earth element (REE) data suggest that their protoliths correspond to basalts and basaltic andesites of tholeiitic and calc-alkaline affinity. The metavolcanic rocks likely formed by 2.5–4 % partial melting of a subcontinental lithospheric mantle source that was enriched through metasomatism involving sediment-derived melts and subduction-related fluids. The results of this study suggest that the protoliths of the Bikélélé metavolcanic rocks were emplaced in a subduction-related back-arc environment, during the second magmatic episode recorded in the Chaillu Massif and underwent metamorphic grade up to amphibolite facies during the Neoarchean tectono-metamorphic event.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100429"},"PeriodicalIF":0.0,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cr-bearing amphiboles frequently occur in the subcratonic lithospheric mantle of Siberian Craton particularly in northern kimberlite fields like West Ukukit, Kuranakh, Kuoika, Kharamai, as well as in the central part of Yakutia – in Alakit and Daldyn fields and in Aldan and Chompolo fields. In the Leningrad pipe of the West Ukukit field, Cr-bearing amphiboles range from Cr-hornblendes to pargasites, edenites, katophorites, and K-richterites, showing an increase in K and Si content, as well as pressure, as determined using the updated amphibole thermobarometer. The P–T estimates for amphiboles are consistent with the results of garnet thermobarometry, supporting the division into seven horizons (interpreted as paleo-subducted slabs).
Typically, the lower to middle pressure levels and the lithospheric boundary are more heated and Fe-rich, which suggests interaction between melts and peridotites within low-pressure traps for hydrous melts.
K-richterites from the lithosphere–asthenosphere boundary exhibit steeply inclined and enriched trace element patterns, characterized by elevated levels of large ion lithophile elements (LILE), Sr, and Rb, along with pronounced negative anomalies in Nb and Pb. The low to middle pressure Na-rich varieties exhibit peaks in Rb, Ba, and Th, but show significantly lower rare earth element (REE) concentrations with marked depressions in the MREE range. Pargasites and hornblendes display concave REE patterns with distinct Eu anomalies, as well as peaks in Ba, U, and Sr and troughs in high field strength elements (HFSE), reflecting subduction-related signatures. Clinopyroxenes show Th, U, and Sr peaks, indicative of plume-related processes. The pargasites and hornblendes show concave REE patterns with Eu anomalies and Ba, U, Sr peaks and troughs in HFSE reflecting subduction-related signs. Clinopyroxenes reveal Th, U, Sr peaks related to plumes. Amphiboles are commonly Cl-bearing and typically associated with subduction-related processes. In the Leningrad pipe, amphibole ages range from 2.67 Ga – indicating early mantle hydration – to 1370, 500, and 370 Ma, which correspond to re-equilibration during major plume events.
{"title":"Mantle amphiboles from the lithospheric keel of the Siberian Craton: Reconstructions using new thermobarometry and geochemistry","authors":"I.V. Ashchepkov , S.A. Babushkina , S.I. Kostrovitsky , O.B. Oleinikov , A.V. Travin , D.S. Yudin , A.S. Ivanov , N.S. Medvedev","doi":"10.1016/j.geogeo.2025.100427","DOIUrl":"10.1016/j.geogeo.2025.100427","url":null,"abstract":"<div><div>Cr-bearing amphiboles frequently occur in the subcratonic lithospheric mantle of Siberian Craton particularly in northern kimberlite fields like West Ukukit, Kuranakh, Kuoika, Kharamai, as well as in the central part of Yakutia – in Alakit and Daldyn fields and in Aldan and Chompolo fields. In the Leningrad pipe of the West Ukukit field, Cr-bearing amphiboles range from Cr-hornblendes to pargasites, edenites, katophorites, and K-richterites, showing an increase in K and Si content, as well as pressure, as determined using the updated amphibole thermobarometer. The P–T estimates for amphiboles are consistent with the results of garnet thermobarometry, supporting the division into seven horizons (interpreted as paleo-subducted slabs).</div><div>Typically, the lower to middle pressure levels and the lithospheric boundary are more heated and Fe-rich, which suggests interaction between melts and peridotites within low-pressure traps for hydrous melts.</div><div>K-richterites from the lithosphere–asthenosphere boundary exhibit steeply inclined and enriched trace element patterns, characterized by elevated levels of large ion lithophile elements (LILE), Sr, and Rb, along with pronounced negative anomalies in Nb and Pb. The low to middle pressure Na-rich varieties exhibit peaks in Rb, Ba, and Th, but show significantly lower rare earth element (REE) concentrations with marked depressions in the MREE range. Pargasites and hornblendes display concave REE patterns with distinct Eu anomalies, as well as peaks in Ba, U, and Sr and troughs in high field strength elements (HFSE), reflecting subduction-related signatures. Clinopyroxenes show Th, U, and Sr peaks, indicative of plume-related processes. The pargasites and hornblendes show concave REE patterns with Eu anomalies and Ba, U, Sr peaks and troughs in HFSE reflecting subduction-related signs. Clinopyroxenes reveal Th, U, Sr peaks related to plumes. Amphiboles are commonly Cl-bearing and typically associated with subduction-related processes. In the Leningrad pipe, amphibole ages range from 2.67 Ga – indicating early mantle hydration – to 1370, 500, and 370 Ma, which correspond to re-equilibration during major plume events.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100427"},"PeriodicalIF":0.0,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-27DOI: 10.1016/j.geogeo.2025.100410
Fahad Abubakar, Felix Bamidele Fatoye, Momohjimoh Abdulsalami, Abdullateef Aliyu
The discovery of iron ore deposits is crucial for Nigeria’s economic diversification. However, the Nigerian Bida Basin’s complex geology, extensive overburden, disputed stratigraphic boundaries and limited surface exposure hinder traditional geological and geophysical exploration methods. This study employs high-resolution aeromagnetic data covering 20,984.48 m² to delineate subsurface geological features and identify potential mineralized zones. Known ore deposits were used for validation. Signal enhancement filters, including the analytic signal (ANS), total horizontal derivative (THD), and Euler deconvolution, were applied to aid data interpretation. Depth estimates for mineralization sources range from 83.06 to 248.53 m (ANS) and 129 to 600 m (Euler). The THD highlights magnetic edge sources, with gradient amplitudes of 0.00008–0.00046 nT/m, covering 4621.42 m² (22%). The ANS refines the geometric configuration of these zones, identifying high-amplitude regions (0.07–0.16 nT/m) across 2989.34 m² (14%). These results strongly align with existing mining sites. Fuzzy membership and fuzzy overlay spatial analysis integrated the geophysical results, identifying 2667.39 m² (12.7%) as highly suitable for future metallic ore exploration. Validation using four known iron ore mining sites confirmed model accuracy, with all sites located within predicted high-potential zones. The predicted high mineralization potential zones are focus areas for further exploration and development. While the findings demonstrate the effectiveness of integrated geophysical enhancements in complex terrains, future exploration should incorporate ground-truth validation and economic feasibility assessments to refine exploration accuracy and ensure resource viability.
铁矿石储量的发现对尼日利亚的经济多样化至关重要。然而，尼日利亚Bida盆地复杂的地质、广泛的覆盖层、有争议的地层边界和有限的地表暴露，阻碍了传统的地质和地球物理勘探方法。利用20984.48 m²的高分辨率航磁数据，圈定地下地质特征，识别潜在矿化带。已知的矿床被用于验证。信号增强滤波器，包括分析信号（ANS）、总水平导数（THD）和欧拉反卷积，用于辅助数据解释。成矿源深度估计范围为83.06 ~ 248.53 m （ANS）和129 ~ 600 m （Euler）。THD突出磁边源，梯度幅值为0.00008 ~ 0.00046 nT/m，覆盖面积为4621.42 m²（22%）。ANS细化了这些区域的几何结构，确定了2989.34 m²（14%）的高振幅区域（0.07-0.16 nT/m）。这些结果与现有的采矿地点非常吻合。模糊隶属度和模糊叠加空间分析综合了物探结果，确定2667.39 m²（12.7%）为未来高度适合找矿的区域。使用四个已知的铁矿石开采地点进行验证，证实了模型的准确性，所有地点都位于预测的高潜力区域内。预测的高成矿潜力带是今后勘探开发的重点区域。虽然研究结果证明了综合地球物理增强在复杂地形中的有效性，但未来的勘探应结合地面真实性验证和经济可行性评估，以提高勘探精度并确保资源可行性。
{"title":"Aeromagnetic delineation of iron ore deposits in a complex geological terrain aided by fuzzy logic","authors":"Fahad Abubakar, Felix Bamidele Fatoye, Momohjimoh Abdulsalami, Abdullateef Aliyu","doi":"10.1016/j.geogeo.2025.100410","DOIUrl":"10.1016/j.geogeo.2025.100410","url":null,"abstract":"<div><div>The discovery of iron ore deposits is crucial for Nigeria’s economic diversification. However, the Nigerian Bida Basin’s complex geology, extensive overburden, disputed stratigraphic boundaries and limited surface exposure hinder traditional geological and geophysical exploration methods. This study employs high-resolution aeromagnetic data covering 20,984.48 m² to delineate subsurface geological features and identify potential mineralized zones. Known ore deposits were used for validation. Signal enhancement filters, including the analytic signal (ANS), total horizontal derivative (THD), and Euler deconvolution, were applied to aid data interpretation. Depth estimates for mineralization sources range from 83.06 to 248.53 m (ANS) and 129 to 600 m (Euler). The THD highlights magnetic edge sources, with gradient amplitudes of 0.00008–0.00046 nT/m, covering 4621.42 m² (22%). The ANS refines the geometric configuration of these zones, identifying high-amplitude regions (0.07–0.16 nT/m) across 2989.34 m² (14%). These results strongly align with existing mining sites. Fuzzy membership and fuzzy overlay spatial analysis integrated the geophysical results, identifying 2667.39 m² (12.7%) as highly suitable for future metallic ore exploration. Validation using four known iron ore mining sites confirmed model accuracy, with all sites located within predicted high-potential zones. The predicted high mineralization potential zones are focus areas for further exploration and development. While the findings demonstrate the effectiveness of integrated geophysical enhancements in complex terrains, future exploration should incorporate ground-truth validation and economic feasibility assessments to refine exploration accuracy and ensure resource viability.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100410"},"PeriodicalIF":0.0,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144704100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-27DOI: 10.1016/j.geogeo.2025.100412
Anamika Pandey, Birendra Pratap
Aquifer parameters are crucial for effectively managing groundwater resources. A geoelectrical survey was conducted in parts of Mirzapur District, Uttar Pradesh, India, involving twenty-four vertical electrical soundings (VES) to characterize the aquifers and evaluate contamination levels. The Dar-Zarrouk parameters, such as longitudinal unit conductance, total transverse unit resistance, anisotropy and, aquifer parameters, were determined to characterize the aquifers and estimate their protective capacity. Transmissivity (T) values ranged from 65.32 to 49,310.05 m2/day, with an average of 24,687.69 m2/day. The study indicated a high groundwater potential in areas with overburden thickness exceeding 13 m and a reflection coefficient below 0.8. In regions with overburden thickness greater than 13 m and a reflection coefficient of 0.8 or higher, a medium groundwater potential was observed. The groundwater protective capacity assessment revealed that most locations have moderate to good protection levels. This study aids in identifying aquifer vulnerability and guiding future groundwater resource development.
{"title":"Aquifer characterization and protective capacity evaluation using geoelectrical measurements in parts of Vindhyan Supergroup, Uttar Pradesh, India","authors":"Anamika Pandey, Birendra Pratap","doi":"10.1016/j.geogeo.2025.100412","DOIUrl":"10.1016/j.geogeo.2025.100412","url":null,"abstract":"<div><div>Aquifer parameters are crucial for effectively managing groundwater resources. A geoelectrical survey was conducted in parts of Mirzapur District, Uttar Pradesh, India, involving twenty-four vertical electrical soundings (VES) to characterize the aquifers and evaluate contamination levels. The Dar-Zarrouk parameters, such as longitudinal unit conductance, total transverse unit resistance, anisotropy and, aquifer parameters, were determined to characterize the aquifers and estimate their protective capacity. Transmissivity (T) values ranged from 65.32 to 49,310.05 m<sup>2</sup>/day, with an average of 24,687.69 m<sup>2</sup>/day. The study indicated a high groundwater potential in areas with overburden thickness exceeding 13 m and a reflection coefficient below 0.8. In regions with overburden thickness greater than 13 m and a reflection coefficient of 0.8 or higher, a medium groundwater potential was observed. The groundwater protective capacity assessment revealed that most locations have moderate to good protection levels. This study aids in identifying aquifer vulnerability and guiding future groundwater resource development.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100412"},"PeriodicalIF":0.0,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-25DOI: 10.1016/j.geogeo.2025.100425
Oghenevovwero E. Esi , Orisekpabor P. Odedede , Moses O. Eyankware
The solid waste contaminated leachate may cause radiological human risk when it comes in contact with the aquifer groundwater. To ascertain the radiological contamination level of research area, the electrical resistivity method was used to assess the depth of the aquifer of the groundwater and radiometric survey analytical method were used to assessed the radiological human risk. The electrical resistivity Dar-Zarrouk parameters longitudinal conductance (S), transverse resistance (Tr), longitudinal resistance (L) and aquifer properties such as transmissivity (T) and hydraulic conductivity (K) used to evaluate groundwater potential revealed that Aladja had higher values of Tr compared to other research sites. The values obtained from S also suggested that surface pollution of groundwater is a possibility. The research area's Effurun axis was the location of the highest value of ρL. Subsequent investigation indicated that high K values were found in the research area near the Ogunu and Warri axes. A total of 18 water samples were collected for a radiometric survey and mean measured results of 238U, 232Th and 40K are 6.57 ± 2.89Bql-1, 3.23 ± 1.25Bql-1 and 53.21 ± 3.51Bql-1 respectively. The obtained mean results exceeded the permissible limits of 1.0 Bql-1, 0.1 Bql-1, and 10 Bql-1 respectively. The computed radiological parameter results are all slightly higher than standard. The results prove that the studied groundwater will be detrimental to human health with time. Deductions from the study revealed that groundwater quality should be monitored and that suitable treatment technologies should be used to filter the water before drinking.
{"title":"Integration of geophysical and radiological assessment of solid waste diposal impact on groundwater and human health in Southern Nigeria","authors":"Oghenevovwero E. Esi , Orisekpabor P. Odedede , Moses O. Eyankware","doi":"10.1016/j.geogeo.2025.100425","DOIUrl":"10.1016/j.geogeo.2025.100425","url":null,"abstract":"<div><div>The solid waste contaminated leachate may cause radiological human risk when it comes in contact with the aquifer groundwater. To ascertain the radiological contamination level of research area, the electrical resistivity method was used to assess the depth of the aquifer of the groundwater and radiometric survey analytical method were used to assessed the radiological human risk. The electrical resistivity Dar-Zarrouk parameters longitudinal conductance (<em>S</em>), transverse resistance (<em>Tr</em>), longitudinal resistance (<em>L</em>) and aquifer properties such as transmissivity (<em>T</em>) and hydraulic conductivity (<em>K</em>) used to evaluate groundwater potential revealed that Aladja had higher values of <em>Tr</em> compared to other research sites. The values obtained from <em>S</em> also suggested that surface pollution of groundwater is a possibility. The research area's Effurun axis was the location of the highest value of <em>ρ<sub>L</sub></em>. Subsequent investigation indicated that high <em>K</em> values were found in the research area near the Ogunu and Warri axes. A total of 18 water samples were collected for a radiometric survey and mean measured results of <sup>238</sup>U, <sup>232</sup>Th and <sup>40</sup>K are 6.57 ± 2.89Bql<sup>-1</sup>, 3.23 ± 1.25Bql<sup>-1</sup> and 53.21 ± 3.51Bql<sup>-1</sup> respectively. The obtained mean results exceeded the permissible limits of 1.0 Bql<sup>-1</sup>, 0.1 Bql<sup>-1</sup>, and 10 Bql<sup>-1</sup> respectively. The computed radiological parameter results are all slightly higher than standard. The results prove that the studied groundwater will be detrimental to human health with time. Deductions from the study revealed that groundwater quality should be monitored and that suitable treatment technologies should be used to filter the water before drinking.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 1","pages":"Article 100425"},"PeriodicalIF":0.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144911741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-25DOI: 10.1016/j.geogeo.2025.100426
Guozheng Sun , Shuwen Liu , Lintao Wang , Yang Yu , Shengyao Yu , Huahua Cao , Lei Gao , Yalu Hu , Jinghao Fu
The formation, evolution, and geodynamics of the Archean continent is a hot topic in solid earth science. Sanukitoids are the oldest Mg-Fe-K-rich granitoid magmas recognized so far on Earth, and their crust-mantle interaction process is a golden key to deciphering the formation and evolution of early continental crust. Sanukitoid suites consist of late Archean (3.0–2.5 Ga-old) plutonic rocks ranging from diorites, monzodiorites, and granodiorite, typically with abundant cognate mafic enclaves. Geochemically, they have a mantle signature (high content of Mg, Ni, Cr, and high Mg#) and enrichment in LILE (especially K, Ba, and Sr). It is generally believed that Archean sanukitoids originated from an enriched or metasomatized lithospheric mantle source, and its parental magmas are water-rich and highly oxidized, which is probably genetically related to gold mineralization. Here we compile the geochemical data for late Neoarchean (2.6–2.5 Ga) sanukitoids from the North China Craton and conduct a systematic petrogenetic classification. The less-differentiated sanukitoid magma (SiO2 < 62 wt%) was controlled by multiple factors such as metasomatic component, metasomatic degree, and melting P-T conditions, indicating that near-surface weathering had already existed in the late Archean. The differentiated sanukitoids (SiO2 > 62 wt%) were formed by extensive fractional crystallization of less-differentiated sanukitoid melts, accompanied by crust-mantle magmatic mixing. These late Neoarchean sanukitoids are distributed sporadically throughout the North China Craton without zonation. Combined with other evidence of magmatism, metamorphic deformation, and thermodynamic numerical modeling, we propose that the sanukitoids may develop under the microplate tectonic regime, characterized by small-scale and short-term warm subduction.
{"title":"Late Neoarchean sanukitoids in the North China Craton: A geodynamic perspective","authors":"Guozheng Sun , Shuwen Liu , Lintao Wang , Yang Yu , Shengyao Yu , Huahua Cao , Lei Gao , Yalu Hu , Jinghao Fu","doi":"10.1016/j.geogeo.2025.100426","DOIUrl":"10.1016/j.geogeo.2025.100426","url":null,"abstract":"<div><div>The formation, evolution, and geodynamics of the Archean continent is a hot topic in solid earth science. Sanukitoids are the oldest Mg-Fe-K-rich granitoid magmas recognized so far on Earth, and their crust-mantle interaction process is a golden key to deciphering the formation and evolution of early continental crust. Sanukitoid suites consist of late Archean (3.0–2.5 Ga-old) plutonic rocks ranging from diorites, monzodiorites, and granodiorite, typically with abundant cognate mafic enclaves. Geochemically, they have a mantle signature (high content of Mg, Ni, Cr, and high Mg#) and enrichment in LILE (especially K, Ba, and Sr). It is generally believed that Archean sanukitoids originated from an enriched or metasomatized lithospheric mantle source, and its parental magmas are water-rich and highly oxidized, which is probably genetically related to gold mineralization. Here we compile the geochemical data for late Neoarchean (2.6–2.5 Ga) sanukitoids from the North China Craton and conduct a systematic petrogenetic classification. The less-differentiated sanukitoid magma (SiO<sub>2</sub> < 62 wt%) was controlled by multiple factors such as metasomatic component, metasomatic degree, and melting <em>P-T</em> conditions, indicating that near-surface weathering had already existed in the late Archean. The differentiated sanukitoids (SiO<sub>2</sub> > 62 wt%) were formed by extensive fractional crystallization of less-differentiated sanukitoid melts, accompanied by crust-mantle magmatic mixing. These late Neoarchean sanukitoids are distributed sporadically throughout the North China Craton without zonation. Combined with other evidence of magmatism, metamorphic deformation, and thermodynamic numerical modeling, we propose that the sanukitoids may develop under the microplate tectonic regime, characterized by small-scale and short-term warm subduction.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100426"},"PeriodicalIF":0.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-18DOI: 10.1016/j.geogeo.2025.100423
Chikezie Chimere Onyekwena , Huabei Liu
Global warming has intensified erratic climatic events, such as increased rainfall, flooding, and rapid drawdown, often triggering slope failures. This study investigates the influence of primary and secondary geotextile reinforcements on the stability of unsaturated soil slopes under rapid and transient drawdown conditions. Seepage forces were analyzed using the effective stress B-bar method and finite element method (FEM), while slope stability was assessed using the limit equilibrium method (LEM) integrated with the unsaturated soil mechanics concepts. Results revealed that the combined use of the primary and secondary geotextile reinforcements significantly improves slope stability by mitigating shear stresses near the slope face, reducing shallow failure surfaces, and ensuring global stability. Drainage-enabled geotextiles were particularly effective, facilitating rapid dissipation of pore pressure, lowering the phreatic surface, and achieving a higher factor of safety (1.790) compared to non-drainage geotextiles (1.439). These findings highlight the dual role of geotextiles in providing reinforcement and drainage, confirming their potential as a sustainable solution for mitigating slope failures during rapid drawdown in the face of climate uncertainty.
{"title":"Stability analysis of geotextile-reinforced unsaturated slope under drawdown conditions","authors":"Chikezie Chimere Onyekwena , Huabei Liu","doi":"10.1016/j.geogeo.2025.100423","DOIUrl":"10.1016/j.geogeo.2025.100423","url":null,"abstract":"<div><div>Global warming has intensified erratic climatic events, such as increased rainfall, flooding, and rapid drawdown, often triggering slope failures. This study investigates the influence of primary and secondary geotextile reinforcements on the stability of unsaturated soil slopes under rapid and transient drawdown conditions. Seepage forces were analyzed using the effective stress B-bar method and finite element method (FEM), while slope stability was assessed using the limit equilibrium method (LEM) integrated with the unsaturated soil mechanics concepts. Results revealed that the combined use of the primary and secondary geotextile reinforcements significantly improves slope stability by mitigating shear stresses near the slope face, reducing shallow failure surfaces, and ensuring global stability. Drainage-enabled geotextiles were particularly effective, facilitating rapid dissipation of pore pressure, lowering the phreatic surface, and achieving a higher factor of safety (1.790) compared to non-drainage geotextiles (1.439). These findings highlight the dual role of geotextiles in providing reinforcement and drainage, confirming their potential as a sustainable solution for mitigating slope failures during rapid drawdown in the face of climate uncertainty.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100423"},"PeriodicalIF":0.0,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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