Geosystems and Geoenvironment最新文献

{"title":"Landslide susceptibility assessment and slope stability analysis of cut slopes along Dumre-Paudhi Bazar road section, western Nepal","authors":"Suraj Adhikari,&nbsp;Subodh Dhakal","doi":"10.1016/j.geogeo.2026.100499","DOIUrl":"10.1016/j.geogeo.2026.100499","url":null,"abstract":"<div><div>Cut slopes in Nepal pose significant threats in hilly regions due to weak geology, steep slopes, rainfall, and seismic activity ultimately causing landslide events. This study aims to assess landslide susceptibility and rainfall-induced cut slope stability analysis along the Dumre-Paudhi Bazar road section using geographic information system (GIS) and the GeoStudio package as this approach of accessing the stability has never been performed in the study area. A total of 36 landslides were mapped, and a landslide susceptibility map was developed using the information value method. Ten key causative factors: slope, aspect, curvature, elevation, rainfall, distance from roads, distance from drainage, topographic wetness index (TWI), land use/land cover, and rock and soil distribution were selected based on field observations, geomorphological conditions, and statistical screening using Pearson and Spearman correlation analyses. The study classified the region into five susceptibility zones: very low, low, medium, high and very high using the natural breaks method. Validation was performed using receiver operating characteristics (ROC) curve, where an area under curve (AUC) values of 0.796 for training data sets and 0.762 for testing data sets were obtained indicating a success rate of 79.6% and a prediction rate of 76.2%.</div><div>To further assess rainfall-induced slope stability, five road cut slopes within medium to very high susceptibility zones were analyzed using the coupled SEEP/W and SLOPE/W approach in GeoStudio under different rainfall scenario. Sensitivity analysis was performed under dry conditions and under rainfall intensities ranging from 50% to 150% of the recorded maximum daily rainfall. The results reveal a consistent reduction in the factor of safety with increasing rainfall intensity due to increased pore water pressure highlighting increased failure potential during heavy precipitation. The integrated approach adopted in this study provides a comprehensive understanding of landslide-prone areas and cut-slope behavior under different rainfall conditions and provides valuable insights for hazard mitigation and road infrastructure planning.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100499"},"PeriodicalIF":0.0,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146187354","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}

{"title":"Investigating structural controls on groundwater potential in parts of southeastern Ghana using geophysical tools to improve access to sustainable groundwater resources","authors":"Elikplim A. Dzikunoo,&nbsp;Yvonne S.A. Loh,&nbsp;Daniel Kwayisi,&nbsp;Prospera S. Sungpour","doi":"10.1016/j.geogeo.2026.100498","DOIUrl":"10.1016/j.geogeo.2026.100498","url":null,"abstract":"<div><div>Groundwater development in crystalline basement rocks is complex due to the discrete variations in the fractures, weathered zones and other geologic constraints which determine groundwater flow. To maximize groundwater exploration in such areas, it is imperative to understand the significance of the interplay between fracture systems as well as weathered zone thicknesses. To characterize these factors that underpin groundwater access in crystalline rocks, a geophysical assessment of parts of the Pan-African Dahomeyide rocks underlying the Akatsi district and parts of the Central Tongu district in southeastern Ghana was completed. Characterization of the fracture or lineament systems together with the weathered zone thickness was done using a multi-scale approach of interpreting airborne magnetic data together with limited direct current (DC) 2D electrical resistivity tomography (2D ERT) data. Based on the magnetic signatures, linear features at different depths and of different lengths were identified with the dominant trends being NE-SW. Inversion of the resistivity data aided in defining the weathered zone thicknesses in connection with established soil types including planosols, cambisols, luvisols, solonetz, gleysols and vertisols found in the area. The combined effects of lineaments and weathered zone thicknesses as a dual-porosity model are discussed in terms of their impact on groundwater development.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100498"},"PeriodicalIF":0.0,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077527","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}

{"title":"R-mode factor analysis of stream sediment geochemical data: A multivariate statistical approach for critical mineral exploration in the Bundelkhand Craton, India","authors":"Apratim Kumar Rai ,&nbsp;Satyabrata Behera ,&nbsp;Alok Kumar ,&nbsp;Vivek P. Malviya","doi":"10.1016/j.geogeo.2026.100496","DOIUrl":"10.1016/j.geogeo.2026.100496","url":null,"abstract":"<div><div>The Bundelkhand Craton, though relatively underexplored compared to other Archean cratons of India, exhibits geological and geochemical similarities with mineralised terrains globally, suggesting its potential to host economic mineralisation. In 21st-century exploration, where large geochemical datasets are available, robust statistical methods are essential to decode intricate patterns hidden within these data. This study applies R-mode factor analysis to centered log-ratio transformed stream sediment geochemical data (2808 samples, 62 elements) from the central Bundelkhand Craton to identify mineralisation-related signatures. Three key factors were extracted, explaining 52% of the total variance: (1) a lithological factor (26%) reflecting granitoid-mafic dyke assemblages, (2) a rare earth element (REE)-rare metal factor (20%) linked to potassic granitoids, and (3) a gold-bismuth-selenium factor (6%) spatially associated with shear zones. The centered log-ratio transformation effectively addressed compositional data constraints, while varimax rotation produced interpretable factors aligned with known geology. Spatial analysis revealed high-priority exploration targets, viz. REE anomalies in the south correlate with alkaline granitoids, while gold-bismuth-selenium anomalies along the Bundelkhand Tectonic Zone and Raksha Shear Zone confirm structurally controlled gold mineralisation. Scandium anomalies, coinciding with Fe-Mg-Ca-rich zones, indicate mafic-ultramafic intrusions. These findings not only validate historical gold occurrences but also reveal new critical mineral potential (Indium, Thalium and Scandium) in the craton. The study demonstrates how multivariate statistics, when integrated with geological knowledge, can transform regional geochemical data into actionable exploration targets. The methodology provides a replicable framework for assessing mineral potential in under-explored cratons, supporting India’s strategic mineral security initiatives.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100496"},"PeriodicalIF":0.0,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077528","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}

{"title":"Quantitative assessment of active tectonics of Chittagong-Tripura Fold Belt, Bengal Basin, Bangladesh","authors":"Md. Sakawat Hossain ,&nbsp;Mery Biswas ,&nbsp;Md. Sharif Hossain Khan ,&nbsp;Dilruba Yesmin Shetu ,&nbsp;Probir Biswas ,&nbsp;Zakia Sultana","doi":"10.1016/j.geogeo.2026.100493","DOIUrl":"10.1016/j.geogeo.2026.100493","url":null,"abstract":"<div><div>The Chittagong-Tripura Fold Belt (CTFB) is part of the active accretionary wedge of the Indo-Burman Ranges (IBR), spanning more than 100 km in width. Although the tectonic evolution and signature of active tectonics are evident from tectonogeomorphic and structural features, the assessment of active tectonics in the CTFB area—especially along the Chittagong Coastal Fault (CCF) and Kaladan Fault—remains limited. The present study attempts to comprehensively analyze fracture orientations and geomorphic features of the area to assess the level of active tectonics. The WSW-ENE generalized compressional direction, deciphered from the fracture set analysis, represents the normal component of present-day Indian Plate motion. Different morphometric parameter values of the seven watresheds in the CTFB area assign the range of the index of active tectonics (IAT): Class 1 is highly active (1.375–1.500), Class 2 is moderately active (1.501–1.875), and Class 3 is low/less active (1.876–2.250). The best-fit curves with the power-law (<em>R</em>² values) for linear, exponential, logarithmic, and power functions for seven master streams from seven watersheds and sixteen other streams from four different regions reflect the relative levels of active tectonics. Overall, the western margin of the CTFB along the Frontal Thrust/CCF appears to be relatively more active than the eastern margin along the Kaladan Fault and is therefore more prone to seismic hazards.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100493"},"PeriodicalIF":0.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037328","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}

{"title":"Stable isotopes and palynological analyses of the Campanian-Maastrichtian Mamu shales, western flank of the Anambra Basin, Nigeria: A paleoenvironmental investigation","authors":"Olugbenga T. Fajemila ,&nbsp;Tesleem O. Kolawole ,&nbsp;Jorge E. Spangenberg ,&nbsp;Moshood A. Olayiwola ,&nbsp;Kehinde O. Akinterinwa ,&nbsp;Kabirat T. Adebiyi ,&nbsp;Rafiu A. Salako","doi":"10.1016/j.geogeo.2026.100492","DOIUrl":"10.1016/j.geogeo.2026.100492","url":null,"abstract":"<div><div>The Mamu Formation is an important sedimentary unit within the Anambra Basin, southern Nigeria. The presence of coal seams and carbonaceous shales within this formation has implications on its hydrocarbon potential and paleoenvironment of deposition. This study integrated stable isotopes of organic carbon and total nitrogen (<em>δ</em>¹³C_org, <em>δ</em>¹⁵N_TN) and palynology to characterize the depositional environment of the Mamu Shales located at the western flank of the Anambra Basin in Nigeria. The <em>δ</em>¹³C_org values ranged from -25.9 to -24.6‰ VPDB, while the <em>δ</em>¹⁵N_TN values varied from 3.0 to 5.6‰ Air-N₂. Additionally, the carbon-to-nitrogen molar ratios (C/N) fell between 10.8 and 19.3. These findings suggest that the organic matter primarily originated from terrestrial C₃ grasses and trees. The range of TOC, HI and T_max values suggested that these shales are good hydrocarbon source rocks. The palynomaceral (PM) assemblages were characterized by abundant, poorly sorted small and medium-sized PM-1 and PM-2, alongside relatively common lath-shaped PM-4. These assemblages were associated with lower occurrences of PM-3, structureless organic matter, and land-derived palynomorphs. Together, these observations indicate a predominantly terrestrial paleoenvironment marked by rainforest vegetation. From the <em>δ</em>¹⁵N_TN values, it appears that symbiotic nitrogen-fixing plants served as the primary nitrogen source for the black shales, which formed in a continental marginal environment. Overall, our results suggest that the episodic incursions of the Trans-Saharan Seaway were minimal at the western flank of the basin, indicating a carbonate-starved paleoenvironment during the Late Cretaceous.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100492"},"PeriodicalIF":0.0,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037329","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}

{"title":"Petrogenesis and tectonomagmatic environment of Naranag granites from Northwestern Kashmir Himalaya, India","authors":"Akhtar R. Mir ,&nbsp;Shamim A. Dar ,&nbsp;Adil A. Bhat ,&nbsp;Naseer A. Bhat ,&nbsp;Irfan M. Bhat ,&nbsp;J. Ukasha ,&nbsp;Vikash Kumar ,&nbsp;Shabber H. Alvi ,&nbsp;V. Balaram ,&nbsp;Santosh Kumar","doi":"10.1016/j.geogeo.2026.100490","DOIUrl":"10.1016/j.geogeo.2026.100490","url":null,"abstract":"<div><div>Granites represent a fundamental component of the continental crust and provide valuable insights into crustal growth, recycling, and tectono-magmatic evolution through Earth’s history. The Early Paleozoic granitoids in the Himalaya are of particular significance as they record the influence of the Pan-African event (ca. 600–500 Ma), a major tectono-thermal event related with the assembly of Gondwana. Despite the occurance of numerous Pan-African granitoids across the Himalaya, several intrusions remain poorly characterized. One such body is the Naranag granites (NG) of the northwestern Himalaya, exposed over ∼15 km² in Ganderbal District, Kashmir. This study integrates detailed field relationships, petrographic observations, and whole-rock geochemistry to investigate the petrogenesis, source characteristics, and tectonic setting of the Naranag pluton. Field observations reveal that the Naranag granites are medium to coarse grained, whitish grey, and largely undeformed, with quartz, k-feldspar, plagioclase, and biotite ± muscovite minerals present. Pegmatitic and aplitic veins with tourmaline reflect late-stage magmatic evolution. Petrographic features, including graphic textures, perthitic intergrowths, and the presence of garnet and tourmaline, confirm a peraluminous, two-mica (S-type) affinity. Geochemical analyses show high SiO₂ (68.7–70.5 wt.%), elevated alkalis (Na₂O + K₂O = 8.3–9.1 wt.%), high alumina saturation indices (ASI =1.65–1.77), and enrichment in large ion lithophile elements (e.g., Rb, Ba, K, Pb) with depletion in high-field-strength elements (e.g., Nb, Ta, Ti). These features, along with negative Ba–Sr anomalies and negative trends of MgO, Al₂O₃, TiO₂, and CaO with SiO₂, reflect partial melting of metagraywacke-dominated lower crust under water-undersaturated conditions, followed by fractional crystallization of feldspars and biotite. Tectonic setting plots (Rb–Y–Nb; Rb vs. Y + Nb) and calc-alkaline affinity indicate emplacement in a syn-collisional to volcanic arc setting, consistent with other Early Paleozoic granitoids of the Himalaya, such as the Hant and Dalhousie granites, and comparable Pan-African intrusions globally. The Naranag granites thus represent a crust-derived melt generated during crustal thickening and orogenic heating associated with the Pan-African tectono-thermal regime. Their geochemical affinity and mineralogical signatures provide evidence for widespread Early Paleozoic granitic magmatism across the Himalaya linked to the assembly of Gondwana. This study highlights the significance of the Naranag granites as a key but previously underexplored record of Pan-African magmatism in the northwestern Himalaya. Future isotopic and geochronological investigations are recommended to refine their emplacement age and further constrain the relative contributions of crustal versus mantle sources in their genesis.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100490"},"PeriodicalIF":0.0,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037330","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}

{"title":"Hydrothermal source and upwelling-related sedimentary accumulation: A new model for early-stage ore forming processes of the western Neotethyan lower Jurassic Úrkút manganese ore deposit","authors":"Máté Zs. Leskó ,&nbsp;Boglárka A. Topa ,&nbsp;Ferenc Móricz ,&nbsp;Ferenc Kristály ,&nbsp;Délia H. Debus-Bulátkó ,&nbsp;Richárd Z. Papp ,&nbsp;Tamás G. Weiszburg ,&nbsp;József Pálfy ,&nbsp;Tamás Vigh ,&nbsp;Péter Majoros ,&nbsp;Lívia Leskóné Majoros ,&nbsp;Norbert Zajzon","doi":"10.1016/j.geogeo.2025.100489","DOIUrl":"10.1016/j.geogeo.2025.100489","url":null,"abstract":"<div><div>The black shale-hosted manganese ore deposit of Úrkút in Hungary formed during the globally recognized Toarcian (Early Jurassic) Jenkyns Event. Although geochemical signatures of hydrothermal processes involved in the metallogenesis of manganese ores were first recognized in the 1980s, their source and geochemical characterisation remained controversial. Here, we address two key questions: (i) why economically significant manganese ore accumulation is exclusively restricted to the Úrkút and Eplény sub-basins, despite the widespread Jenkyns Event-related sedimentation across the Transdanubian Range, and (ii) what was the source of the manganese. Based on new clay mineralogical (identification of montmorillonite and beidellite with distinct formation environments), geochemical (behaviour of Fe and Mn; Co-Ni-Zn and Fe-Mn-(Co-Ni-Cu) ternary system analysis; Cd/Mo ratio), and sedimentological data (evidence for radiolarian blooms), we propose a new early-stage ore-forming model. We suggest that dissolved Fe and Mn from hot brine pools associated with the rifting of the Neotethys Ocean were transported over long distances under anoxic conditions during the Jenkyns Event. A long-lived upwelling system (from the Late Pliensbachian to Early Toarcian) caused water mixing in the Bakony basin, which triggered the precipitation of the “proto-ore” of the Úrkút and Eplény manganese ore deposits. Our results contribute to a better understanding of the manganese enrichment in the Úrkút and Eplény sub-basins, pointing to the critical interplay between global paleoenvironmental events and local depositional settings.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100489"},"PeriodicalIF":0.0,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976559","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}

{"title":"Spectral dispersion matching technique for multi-class spatial-spectral feature detection of REE-fertile lithology in the Samalpatti alkaline–carbonatite complex (SACC) using Hyperion data","authors":"P. Abishek ,&nbsp;N.K. Libeesh ,&nbsp;S. Arivazhagan ,&nbsp;C. Sreejith","doi":"10.1016/j.geogeo.2025.100488","DOIUrl":"10.1016/j.geogeo.2025.100488","url":null,"abstract":"<div><div>The Proterozoic alkaline carbonatite complex, lies along the Samalpatti shear zone, is linked to a post-collisional rift setting in the Southern Granulitic Terrain (SGT), provides a geologically intriguing and economically prospective terrain for rare earth element (REE) exploration. This study involves a multiproxy approach by integrating the hyperspectral remote sensing, machine learning, and field validation techniques to delineate the REE fertile lithology units using the EO-1 Hyperion imagery. The pre-processed dataset was subjected to noise reduction and dimensionality reduction using spectral dispersion matching (SDM) methods. SDM was performed in 3 steps; initially, noise reduction algorithms such as principal component analysis (PCA), independent component analysis (ICA), minimum noise fraction (MNF), and band ratio combinations (BRC) were applied to enhance data quality. This was followed by correlation-based feature selection using support vector machines (SVM), focusing on spectral behaviour. Subsequently, mineralogical characteristics were integrated and validated to emphasize their spectrochemical properties. Among the reduction algorithms, ICA achieved the highest spectral class separability, as confirmed by Jeffries–Matusita distance analysis, with values &gt;1.9 for key lithological pairs. The correlation-based feature selection was performed with a radial basis function (RBF) kernel, yielding an overall accuracy of 85.56% and a Kappa coefficient of 0.80. The multiproxy approach using SDM highlights the efficacy of imaging spectroscopy combined with advanced classification techniques in complex lithological terrains and offers a scalable framework for mineral exploration targeting REE-fertile zones.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100488"},"PeriodicalIF":0.0,"publicationDate":"2025-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976558","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}

{"title":"Electrical resistivity tomography for geohazard assessment in West Lombok’s alluvial plain","authors":"Yayat Sudrajat ,&nbsp;Ilham Arisbaya ,&nbsp;Lina Handayani ,&nbsp;Karit L. Gaol ,&nbsp;M. Maruf Mukti ,&nbsp;Bambang Sugiarto ,&nbsp;Syamsuddin ,&nbsp;Bachtiar W. Mutaqin ,&nbsp;Clément Virmoux ,&nbsp;Franck Lavigne","doi":"10.1016/j.geogeo.2025.100487","DOIUrl":"10.1016/j.geogeo.2025.100487","url":null,"abstract":"<div><div>Electrical resistivity tomography (ERT) is widely used for mapping subsurface conditions and is very useful for assessing geohazards. Variations in resistivity can suggest anomalies that can be linked to fault zones, or sediment layering that specifies a particular body, such as sediment-filled basins, or loose soils that are prone to earthquake amplification, liquefaction, and ground failure. This study examines two alluvial plains in West Lombok: Mataram city (the densely populated capital) and Tanjung (a coastal tourist area). Alluvial plains are especially vulnerable to geohazards because their loose, water-saturated sediments intensify seismic shaking and raise liquefaction risks during earthquakes. Our ERT models show a consistent subsurface structure: sand-dominated layers extending beyond 30 meters, topped by pumice-rich volcanic deposits. In some areas, shallow groundwater (&lt;2 meters deep) was detected, further increasing liquefaction potential. Specific resistivity patterns match known liquefaction features, which suggest historical liquefaction had occurred in Mataram. These results emphasize the importance of combining ERT with direct methods, such as trenching and boreholes, to verify subsurface models and refine hazard assessments.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100487"},"PeriodicalIF":0.0,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790613","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}

{"title":"Origin and paleoenvironmental conditions of iron duricrust in the Paleogene N’kapa Formation, Douala sub-basin, Cameroon","authors":"Kevin Jorex Voufor Tsafack ,&nbsp;Ngong Roger Ngia ,&nbsp;Christopher Fuanya ,&nbsp;Christopher M. Agyingi ,&nbsp;Elie Fosso Menkem ,&nbsp;Alexandrine N’nanga ,&nbsp;Median Yongye ,&nbsp;Ligbwah Victor Wotanie","doi":"10.1016/j.geogeo.2025.100486","DOIUrl":"10.1016/j.geogeo.2025.100486","url":null,"abstract":"<div><div>This paper unravels rarely studied paleoenvironmental conditions and origin of iron duricrust in the Paleogene N’kapa Formation, Douala sub-basin, Cameroon. It integrates petrographic and geochemical techniques (mineralogy, trace, major and REEs elements) and isotope of δ¹⁸O, δD and ⁸⁷Sr/⁸⁶Sr to reconstruct paleoclimate, paleoweathering, paleoredox and paleosalinity, and established mechanisms of formation of iron duricrust. The textures and mineralogy of iron duricrust indicates that they are ferricretes with brecciated to colloform textures composed of hematite, siderite, kaolinite and detrital quartz grains. Paleoclimate proxies revealed humid to semi-arid climate and variation in climatic conditions caused intense-chemical weathering, favouring a change in weathering processes from kaolinitisation to ferricretization. Paleoredox and paleosalinity proxies indicate that the iron duricrust was formed under dysoxic to dominantly oxic conditions in shallow freshwater to somewhat brackish water body with intermediate salinity. The δ¹⁸O, δD and ⁸⁷Sr/⁸⁶Sr composition of the samples indicate post-depositional alteration due to influx of meteoric waters during the duricrusting process. The equilibration with meteoric water reveals that the iron duricrusts formed primarily through supergene enrichment and diagenetic reworking of detrital sediments. However, some contribution from hydrogenous input occurred in lagoonal settings with fluctuating salinity, which probably facilitated the precipitation of iron directly from water. The remobilization of iron led to the formation of secondary hematite, which could possibly be link to early Paleogene climatic variations and eustatic sea-level changes. These findings provide valuable insights into sedimentary mineral enrichment in response to Paleogene environmental dynamics and offer a reference for comparable iron-rich deposits in African basins and other parts of the world.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"5 2","pages":"Article 100486"},"PeriodicalIF":0.0,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840235","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}