Geosystems and Geoenvironment最新文献

{"title":"Geochemistry and petrology of deep seated mantle magmas and their mantle xenoliths and xenocrysts: Applications to the structure and compositions of mantle lithosphere","authors":"Igor V. Ashchepkov , N.V. Chalapathi Rao , Rohit Pandey , Sergei V. Rasskazov","doi":"10.1016/j.geogeo.2025.100388","DOIUrl":"10.1016/j.geogeo.2025.100388","url":null,"abstract":"","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100388"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617922","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":"Mantle amphiboles from the lithospheric keel of the Siberian Craton: Reconstructions using new thermobarometry and geochemistry","authors":"I.V. Ashchepkov ,&nbsp;S.A. Babushkina ,&nbsp;S.I. Kostrovitsky ,&nbsp;O.B. Oleinikov ,&nbsp;A.V. Travin ,&nbsp;D.S. Yudin ,&nbsp;A.S. Ivanov ,&nbsp;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":"2025-11-01","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}

{"title":"Hydrostratigraphic characterization using geoelectrostratigraphic information and hydraulic flow unit analysis for high-resolution aquifer mapping in heterogeneous systems","authors":"Ndifreke I. Udosen ,&nbsp;Kufre R. Ekanem ,&nbsp;Nyakno J. George","doi":"10.1016/j.geogeo.2025.100434","DOIUrl":"10.1016/j.geogeo.2025.100434","url":null,"abstract":"<div><div>Accurate characterization of aquifers requires comprehensive understanding of groundwater hydraulic properties. Traditional aquifer assessment techniques are usually insufficient in characterizing hydrostratigraphic variability, leading to inaccurate prediction of aquifer flow dynamics. To address these limitations, this work integrated geoelectrical stratigraphy with hydraulic flow unit, flow zone indicator, and stratigraphic modified Lorenz plot strategies, the goal being to enhance the resolution of aquifer characterization along river channels and tributaries in Akwa Ibom State, Southern Nigeria. Unlike conventional approaches, the stratigraphic modified Lorenz plot (SMLP) provided a more precise strategy for quantifying permeability distribution within the heterogeneous aquifer system, enabling enhanced prediction of aquifer performance. Furthermore, SMLP delineated flow efficiency across the distinct hydrostratigraphic units. Results indicated the presence of four hydraulic flow units, with individual units exhibiting distinctive transmissivity properties. Computed inclination angles of the four flow units were 34°, 29°, 49°, and 33°, respectively, and these indicated the extent of hydraulic efficiency. Hydraulic flow units 1, 3, and 4 had higher transmissivity and were key conduits for groundwater flow. Hydraulic flow unit 2, on the other hand, had reduced transmissivity, indicating restricted fluid migration. The techniques employed in this study enhanced subsurface characterization and generated high-resolution and cost-effective strategies for delineating high-yield aquifer zones within river channels and tributaries with better accuracy than with use of traditional hydrogeological models. These findings are important for optimizing groundwater resource management in the study area and analogous hydrogeological settings worldwide.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100434"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144724467","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":"Paleoenvironmental reconstruction and carbon and sulfur isotopes perturbation in black shales of the Paleocene Bolander member in the N’kapa Formation, Douala Sub-basin Cameroon","authors":"Ngong Roger Ngia ,&nbsp;Elie Fosso Menkem ,&nbsp;Alexandrine N’Nanga ,&nbsp;Christopher Fuanya ,&nbsp;Median Yongye","doi":"10.1016/j.geogeo.2025.100417","DOIUrl":"10.1016/j.geogeo.2025.100417","url":null,"abstract":"<div><div>Black shales deposited across the Paleocene Bolander member of the N’kapa Formation are considered important source rock and shale gas reservoirs in the Douala sub-basin. However, no studies on organic carbon and sulfur isotopes perturbation, accumulation and enrichment of organic matter in black shales exist in the sub-basin. This paper unravels paleoenvironmental reconstruction, the perturbation of organic carbon and pyrite sulfur isotopes record, and mechanism of organic matter enrichment in black shales of the Kompina-Mian and Pendanboko-Kombe areas. Multiple geochemical techniques: organic carbon isotope (δ¹³C_org), pyrite sulfur (δ³⁴S_py), TOC, total sulfur abundance (TS), elemental geochemistry, mineralogy and SEM were used. Paleoclimate proxies indicates that the paleoclimatic condition was mildly-warmer and more humid. Bivariate plots and discriminant functions diagrams to delineate between active and passive tectonic settings such as DF1&amp;2(Arc-Rift-Col)_M1, DF1&amp;2(Arc-Rift-Col)_M2 and DF(A-P)_M revealed that the rocks were sourced from felsic rocks with a passive tectonic setting, with little contribution from active setting. Paleoweathering proxies revealed that the source area experienced moderate chemical weathering as a result of variation in climate and sea-level changes. The proxies for paleoredox and paleosalinity conditions revealed that the sediments were deposited under anoxic sulphidic benthic brackish-water with intermediate salinity. Paleoproductivity parameters like Ba-bio, δ³⁴S_py, δ¹³C_org, TOC, Mo/Al, Cu/Al and S/¹³C_org ratios revealed that climate, brackish-water and anoxia conditions were suitable for high primary productivity and preservation of organic matters. The depleted δ¹³C_org values and negative excursion along the black shale bed results from sulfate-reducing bacteria and chemoautotrophy-mediated carbon cycling under anoxia conditions. While depleted δ³⁴Spy contents are results from biological fractionation during microbial sulfate reduction (MSR), generating pyrite framboids in sediment under strong restrictive conditions with low oxygenation. The mechanism of organic matter accumulation and enrichment demonstrates that δ¹³C_org and δ³⁴Spy was anaerobically recycled by sulphate reducing bacteria and MSR processes, and the caping of benthic black shales by mudstones at shortened exposure duration, caused high primary productivity in anoxic waters. The data of this study demonstrate large climatic and oceanic anoxia fluctuations during the Paleocene influenced peleoweathering, paleosalinity, primary productivity, carbon and sulfur isotopes perturbation, and accumulation and enrichment of organic matter.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100417"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864516","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":"Proterozoic arc magmatism from the Padhar mafic-ultramafics in Betul Belt, Central India Tectonic Zone: Insight from petrography, bulk rock and in-situ trace element geochemistry","authors":"M. Lachhana Dora ,&nbsp;Hassan M. Helmy ,&nbsp;Rajkumar Meshram ,&nbsp;Nathala K. Rao ,&nbsp;Mohamad Shareef ,&nbsp;Raghuram ,&nbsp;Vivek P. Malviya ,&nbsp;Tushar Meshram ,&nbsp;Srinivas Rao Baswani ,&nbsp;Mohammad Atif Raza ,&nbsp;Kirtikumar Randive","doi":"10.1016/j.geogeo.2025.100383","DOIUrl":"10.1016/j.geogeo.2025.100383","url":null,"abstract":"<div><div>This study presents the first identification of an Alaskan-type intrusion within the late-Proterozoic Padhar mafic-ultramafic complex (PMUC), situated along the Central Indian Tectonic Zone (CITZ). The intrusion exhibits a differentiated composition, including peridotite, pyroxenites, hornblende gabbros and diorite. We adopt an integrated approach that combines field studies with analyses of major oxides, in-situ trace elements, and rare-earth element geochemistry. The field evidences of PMUC displays concentric zoning, with a core of dunite surrounded by wehrlite, olivine clinopyroxenite, clinopyroxenite, hornblende clinopyroxenite, and gabbro akin to Alaskan type intrusions. The primary minerals in the PMUC include olivine (forsterite), pyroxene (Cpx and Opx), amphibole, phlogopite, chromite, and magnetite, while secondary minerals like serpentine, chlorite, and talc are also present. The increase in magnesian number (Mg#) of olivine (70–77), orthopyroxene (53–73), and clinopyroxene (67–88) from mafic to ultramafic units indicates differentiation from a common parent melt. The geochemical signature, including negative Nb and Zr anomalies and positive Rb anomalies, suggests fluid metasomatism from slab sediments. The presence of a hydrous parent magma is inferred from the Mg# of early-formed olivine and high amphibole content. Tectonic discrimination plots of pyroxene and amphibole minerals, combined with <em>in-situ</em> trace element chemistry and bulk rock geochemistry, indicate an arc-related origin. The data suggest fluid-driven subduction zone metasomatism, characteristic of Proterozoic Alaskan-type tectonics within the CITZ. Platinum-group element geochemistry shows a high (Pt + Pd)/(Ir + Ru) ratio, similar to that of intrusive rocks of Alaskan types. Geological and geochemical data further support that the PMUC represents a shallow-level (ca. 17 km) segment of a Proterozoic arc, with minor ultramafic units acting as conduits for arc magma in the Betul Belt.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100383"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617247","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":"Late Neoarchean sanukitoids in the North China Craton: A geodynamic perspective","authors":"Guozheng Sun ,&nbsp;Shuwen Liu ,&nbsp;Lintao Wang ,&nbsp;Yang Yu ,&nbsp;Shengyao Yu ,&nbsp;Huahua Cao ,&nbsp;Lei Gao ,&nbsp;Yalu Hu ,&nbsp;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 (SiO₂ &lt; 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 (SiO₂ &gt; 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":"2025-11-01","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}

{"title":"Integrated pore size and grain size characterization of geomaterials from Ewekoro, Eastern Dahomey Basin","authors":"Olawale Babatunde Olatinsu ,&nbsp;Mathew Osaretin Ogieva ,&nbsp;Kehinde Saheed Ishola ,&nbsp;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>_i), skewness (<em>SK_i</em>), and kurtosis (<em>K_G</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>_z values reveal more of medium/coarse grain composition across samples, implying an intermediate to high energy depositional environment. <em>σ</em>_i values indicate poor to medium sorting which reveals that the rock sediments were likely deposited in fluvial-continental environments. <em>K_G</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":"2025-11-01","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}

{"title":"Spatiotemporal rainfall trend analysis and drought identification in agro-climatic zones of Odisha, Eastern India","authors":"Laxmikanta Rana ,&nbsp;Siba Sankar Sahu ,&nbsp;Bubun Mahata ,&nbsp;Mukul Maity ,&nbsp;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":"2025-11-01","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}

{"title":"Impact of geofactors on landslide susceptibility using weighted overlay method: An integrated GIS and field-based analysis on NH-07, Chamoli, Uttarakhand","authors":"Haritabh Rana,&nbsp;Tahir Mushtaq,&nbsp;Ranjith Anburaj","doi":"10.1016/j.geogeo.2025.100420","DOIUrl":"10.1016/j.geogeo.2025.100420","url":null,"abstract":"<div><div>The Himalayan Belt is notably at risk for landslide occurrences, which are directly related to the region's development and economic well-being. The study area encompasses Tangni to Vishnuprayag road sector, National Highway-07 (NH-07) in Chamoli district of Uttarakhand. The primary objective of this study is to identify the zones susceptible to landslides within the region, thereby contributing to the reduction of landslide disaster risks. Knowledge driven weighted overlay method (WOM) integrating GIS and field based multiple geofactor maps has been used where each thematic map was given a rating and weighting process utilizing a heuristic approach which facilitated the generation of a landslide susceptibility map, separately for the rock and debris domain of the region. Seventy-three landslides along the road corridor and its surrounding areas, establishing a correlation between their spatial distribution and various geotechnical parameters have been considered for this study. The resulting susceptibility map documenting 73 nos. of landslide incidences in the study area indicates that low susceptibility zone accounts for 49 % of the area accomodating 8 % (06 nos.) of the total landslide incidences. The moderate susceptibility zone accounts for 30 % of the area but has 19 % (14 nos.) of the total landslide incidences and the high susceptibility zone accounts for 21 % of the area but has 73 % (53 nos.) of the total landslide incidences. Validation of the susceptibility map was conducted against historical landslide data and field observations, which confirmed its reliability. This integrated approach of WOM serves as a significant resource for land-use planning and disaster risk reduction in landslide-prone areas of the Himalayas. Furthermore, it illustrates the efficacy of the WOM for mapping landslide susceptibility, providing a replicable framework for similar terrains both within the Himalayas and in other regions.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100420"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522751","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":"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 ,&nbsp;Noël Watha-Ndoudy ,&nbsp;Hardy Medry Dieu-Veill Nkodia ,&nbsp;Anthony Temidayo Bolarinwa ,&nbsp;Aliyu Ohiani Umaru ,&nbsp;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 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.</div></div>","PeriodicalId":100582,"journal":{"name":"Geosystems and Geoenvironment","volume":"4 4","pages":"Article 100429"},"PeriodicalIF":0.0,"publicationDate":"2025-11-01","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}