Asian Journal of Geological Research

Delineation of Metallic Mineralization Zones using Integrated Aeromagnetic and Geochemical Data in the Basement Rocks of Oba-Akoko Area, Southwestern Nigeria

2026-06-10T09:57:41+00:00

The Oba Akoko area, southwestern Nigeria, lies within the Precambrian Basement Complex and is characterized by complex lithological units and Pan-African structural deformation. This study delineates metallic mineralization zones using integrated aeromagnetic and geochemical data. Fifteen (n = 15) geochemical samples were analyzed. Aeromagnetic data were processed to produce Total Magnetic Intensity (TMI), First Vertical Derivative (FVD), Euler deconvolution (structural index = 1), and lineament maps, with Euler depth solutions indicating shallow-to-moderate structural sources. Geochemical analysis involved ICP-MS following four-acid (HNO₃–HCl–HF–HClO₄) digestion with 0.45 µm filtration. Statistical evaluation used correlation analysis and Principal Component Analysis (PCA). Aeromagnetic results reveal dominant NE–SW to ENE–WSW structural trends interpreted as deep-seated faults and shear zones controlling crustal deformation and hydrothermal fluid migration. Magnetic highs correspond to mafic rocks, while lows indicate felsic or hydrothermally altered zones. Lineament and Euler analyses highlight structurally dense and highly prospective zones, particularly within the Ikun–Afo corridor. Geochemical results show significant enrichment in IKUN samples with Cu, Zn, Pb, Co, Ni, and Cr relative to background OBA values. PCA identifies hydrothermal (Cu–Zn–As–Pb–Co), lithological (Mo–Th), and mafic (Ni–Cr) associations, while correlation analysis confirms strong Cu–Zn–Pb relationships indicative of sulfide-related hydrothermal processes. Integration of both datasets reveals a strong structural control on geochemical anomalies, with consistent spatial coincidence between fault zones and elemental enrichment. The Ikun–Afo–Okeusi–Oka corridor is identified as the most prospective zone for metallic mineralization due to overlapping geophysical and geochemical signatures. This study confirms the effectiveness of integrated aeromagnetic and geochemical methods for mineral prospectivity mapping in Precambrian basement terrains.

Granulometric Characteristics and Heavy Mineral Composition of Igbokoda Beach Sands, Ondo State, Southwestern Nigeria

2026-06-13T11:39:12+00:00

Analysis of grain size distribution has been widely used by sedimentologists to classify sedimentary environments and elucidate transport dynamics. Grain size and heavy mineral content analysis of Igbokoda beach sands, Ondo State, Southwestern Nigeria was carried out to determine the provenance, maturity, industrial and economic significance as well as the economic prospect of the heavy minerals present in the beach sands. For the purpose of this study, a total number of ten (10) beach sand samples were collected along the beach sides in Igbokoda for laboratory analyses. For grain size and heavy mineral content analyses, granulometric and heavy mineral content analyses were carried out on the samples. Grain size analysis was determined by dry sieving the sediments. Granulometric analyses of Igbokoda beach sands showed that Igbokoda beach sands are predominantly fine-medium, clay-free, well-sorted, near symmetrical-fine skewed beach sands with mesokurtic-leptokurtic types ranging from 2.000 mm to 0.063 mm. From the provenance study, the samples were observed to be mature and predicted to have been sourced from a distal source. Heavy mineral content investigation was carried out using heavy mineral separation techniques, which involve using separating funnels and tetrabromoethane, which make up 6-15% of the weight of Igbokoda beach sands. For the purpose of this study, samples were collected from the various sections of the Igbokoda beach sides. For the first section of the beach side, the percentage of concentration of ilmenite is the highest, followed by zircon, pyroxene, rutile, with subordinate amounts of epidote, augite, garnet, apatite, spinel, staurolite and tourmaline. In the second section, almost similar results to the first section were obtained, except in some cases, that is, the concentration of ilmenite and magnetite is lesser, covellite and kyanite are present. From the results, Igbokoda beach sands are predicted to have been sourced from a continental environment and consist of intrusive granitic, metamorphosed and partly sedimentary rock types. However, the beach sands are derived predominantly from intermediate source(s), probably granodiorite. The presence and abundance of heavy minerals like augite, rutile, tourmaline, pyroxene, zircon and others in the bulk composition of the beach sands supports the influence of granitic, gneissic, granodioritic and schistosity sources from nearby crystalline basement complex. Igbokoda beach sands serve various industrial purposes such as filtration, production of glassware and construction.

Geoelectrical Investigation of Groundwater Potential in the Hard Rock Terrain: A Case Study from Lokapavani River Basin, Mandya District, Karnataka

2026-06-15T13:28:58+00:00

Groundwater in crystalline basement regions is mainly stored in weathered and fractured zones due to the low permeability of fresh bedrock, making its distribution highly variable and dependent on subsurface structural features. Accurate identification of these aquifer zones is therefore essential for sustainable groundwater exploration and management in hard rock terrains. The present study investigates groundwater potential in the hard rock terrain of the Lokapavani River Basin, Mandya District, Karnataka, using the Vertical Electrical Sounding (VES) technique. Twenty-one VES stations were conducted employing the Schlumberger electrode configuration using a resistivity meter (SSR-MP-ATS), with fixed potential electrode spacing (MN/2 = 5 m) and current electrode spacing (AB/2) varying from 10 m to 100 m. Apparent resistivity data were analyzed qualitatively through comparative log–log sounding curves to delineate subsurface geoelectrical variations associated with groundwater occurrence. The interpreted apparent resistivity values range from less than 30 Ωm to greater than 7000 Ωm, reflecting considerable lateral and vertical heterogeneity in subsurface conditions. The VES curves revealed predominantly three- to four-layer geoelectrical models characteristic of crystalline basement terrains. The interpreted subsurface conditions indicate the presence of conductive clayey layers, moderately resistive weathered/fractured basement zones and highly resistive fresh basement formations. Locations characterized by moderate resistivity increase with depth are interpreted as favorable groundwater zones, whereas zones exhibiting very high resistivity values correspond to compact basement rocks with low groundwater potential. The study demonstrates that electrical resistivity sounding is an effective and economical technique for groundwater exploration in hard rock terrains and provides valuable information for sustainable groundwater resource development in the study area.

Depth Estimation of Magnetic Sources in Katsina State, North-Western Nigeria, Using Aeromagnetic Data

2026-06-26T10:43:56+00:00

This study estimates depths to magnetic sources in Katsina State, north-western Nigeria, using high-resolution aeromagnetic data from eight sheets: Ruma (Sheet 33), Katsina (Sheet 34), Dutsin Ma (Sheet 55), Musawa (Sheet 65), Funtua (Sheet 78), Malumfashi (Sheet 79), Maska (Sheet 101) and Zaria (Sheet 102). The work applies three depth-estimation techniques, namely 3D Euler deconvolution, source parameter imaging (SPI) and analytic signal (AS) depth estimation, to support the interpretation of subsurface structures relevant to mineral exploration. The total magnetic intensity map shows values between 32,933.563 and 33,079.871 nT, reflecting contrasts associated with lithology and structural features. Depth estimates range from 9.039 m, obtained from SPI, to 1,060.994 m, obtained from AS. Shallow magnetic sources, generally less than 150 m deep, occur mainly in the south-eastern sector around Mai-Jiriya and Gwarzo and in the north-western sector around Charanchi and Mani. A NW-SE-trending dyke-like feature through Mahazu and Ungwan Gagarau is consistently indicated at depths of 150-350 m by the three methods, including Euler deconvolution using a structural index of 1. Deeper sources, exceeding 600 m, occur in the north-eastern part of the area and are interpreted as comparatively thick basement rocks. SPI provided useful imaging of undulating basement topography, whereas Euler deconvolution was more effective for structural depth estimation. The agreement among the methods strengthens the interpretation of shallow magnetic sources that coincide with zones of high analytic signal amplitude and structural density. The results identify areas of potential near-surface mineralisation within the Katsina sector of the Schist Belt, subject to ground-based validation and drilling.

Integrated Geophysical and GIS-Based Analysis of Facies Control on Groundwater Flow Direction in Uromi, Edo State, Nigeria

2026-06-27T10:48:04+00:00

This study evaluates the influence of lithofacies variation on groundwater flow direction in Uromi, Edo State, Nigeria, using integrated electrical resistivity surveying and GIS-based spatial analysis. Three Vertical Electrical Sounding (VES) stations were occupied using the Schlumberger electrode configuration, with current electrode spacing extended to 700 m. Resistance measurements obtained with a terrameter were converted to apparent resistivity and interpreted through curve matching and inversion to infer geoelectric layers and lithological variation. GPS coordinates of survey locations were processed in ArcGIS 9.2 for spatial interpolation, facies delineation and groundwater flow interpretation. The apparent resistivity values ranged from 6.20 to 8957.4 Ωm, indicating a heterogeneous subsurface composed mainly of alternating clay, sandstone and lignite-bearing units. The interpreted geoelectric sections show aquiferous intervals associated principally with medium- to coarse-grained sandstone units at greater depths, reflecting comparatively favourable groundwater storage and transmission conditions. The resistivity curves generally display A-type characteristics, suggesting increasing resistivity with depth. GIS-based interpretation indicates a lateral facies transition from kaolin-rich sandstone to lateritic sandstone across the study area. This variation is inferred to influence groundwater movement by creating contrasts in permeability, with the predominant flow direction interpreted as southwest to northeast. Inferred hydraulic conductivity values range from approximately 10⁻⁹ to 10⁻³ m/s, with seepage velocities of about 10⁻⁹ to 10⁻⁴ m/s, increasing from kaolin-rich units to lateritic and coarse sandstone facies. The findings indicate that lithofacies heterogeneity exerts an important control on groundwater flow behaviour in the study area and demonstrate the value of combining geophysical data with GIS-based spatial analysis for preliminary groundwater assessment in sedimentary terrains.

Shrinkage Characteristics of Soils under Varying Geological Formations in a Humid Tropical Environment of Southeastern Nigeria

2026-06-27T10:56:21+00:00

This study evaluated the shrinkage characteristics and shrink–swell susceptibility of soils developed from different geological parent materials in a humid tropical environment of southeastern Nigeria. Soil samples were collected from three parent materials: Coastal Plain Sand at Eziobodo, Imo Clay Shale at Amuro, and False Bedded Sandstone at Uturu. Samples were obtained from two depths, 0–30 cm and 30–60 cm, with four replicates per depth, giving a total of 24 soil samples. The samples were analysed for selected physical, chemical, and shrinkage-related properties, including particle size distribution, volumetric moisture content, bulk density, soil pH, soil organic matter, effective cation exchange capacity, liquid limit, plastic limit, plasticity index, coefficient of linear extensibility, volumetric shrinkage, and clay activity. Data were subjected to analysis of variance, and treatment means were separated using the least significant difference test at the 5% probability level. The results showed clear differences in soil properties among the parent materials. Coastal Plain Sand soils had the highest sand content of 853 g kg⁻¹, while False Bedded Sandstone soils recorded the highest silt and clay contents of 602 g kg⁻¹ and 260 g kg⁻¹, respectively. Volumetric moisture content ranged from 88.40 to 342.61 g kg⁻¹, while bulk density ranged from 1.51 to 1.66 g cm⁻³. Shrinkage indices were higher in soils derived from False Bedded Sandstone and Imo Clay Shale than in Coastal Plain Sand soils. False Bedded Sandstone recorded the highest liquid limit, plasticity index, coefficient of linear extensibility, and volumetric shrinkage values, while Coastal Plain Sand showed little or no measurable shrinkage response. The findings indicate that geological parent material strongly influences soil shrinkage behaviour in the study area.

Geophysical Investigation of Uke-Ideani and Environs in Southeastern Nigeria

2026-07-02T13:11:04+00:00

Groundwater is an important source of water supply for communities in southeastern Nigeria, and reliable subsurface information is required for effective groundwater exploration and borehole siting. This study presents a geophysical investigation of Uke-Ideani and adjoining areas in Anambra State, southeastern Nigeria, using the electrical resistivity method. Five Vertical Electrical Sounding (VES) stations were occupied using the Schlumberger electrode configuration, with a maximum half-current electrode spacing of 160 m. Field resistance measurements were converted to apparent resistivity values and interpreted to determine subsurface layer resistivities, thicknesses, depths, and inferred lithological units. Geoelectric sections were constructed to assess vertical and lateral variations in lithology and aquifer occurrence. Aquifer parameters, including longitudinal conductance, transverse resistance, hydraulic conductivity, and transmissivity, were estimated from the interpreted geoelectrical data. The results indicate four to five geoelectric layers across the investigated locations, consisting mainly of topsoil, clay, sandy clay, clayey sand, sandstone, and water-saturated sandstone. The principal aquifer units occur within sandstone layers, with aquifer resistivity values ranging from 92.8 to 1539 Ωm. The interpreted aquifer depths vary from 22.6 m at Alor to 97.1 m at Uke, showing spatial variation in groundwater occurrence across the area. Estimated hydraulic conductivity values range from 0.00064 to 0.01077 m/day, while transmissivity values range from 0.0512 to 0.677433 m²/day. These values indicate low to moderate groundwater potential, with Uke, Ojoto, Alor, and Nnobi showing moderate transmissivity and Umuoji showing comparatively low transmissivity. The findings indicate that electrical resistivity sounding can delineate aquifer geometry and support groundwater development decisions in the study area.

Structural Discontinuities and Reservoir Fluid Flow Patterns in Yowi Field, Offshore Niger Delta, Nigeria

2026-07-02T13:21:27+00:00

Structural discontinuities, including faults and fractures, can influence reservoir connectivity, fluid mobility and production response. This study evaluates how structural discontinuities relate to reservoir fluid-flow behaviour in the N5.2 reservoir of the Yowi Field, offshore Niger Delta, Nigeria. The work integrates 3D seismic interpretation, ant-tracking attributes, well-log analysis, core observations, CT-scanned core plugs, petrophysical modelling and production-performance data. Structural interpretation shows that the field is characterised by a rollover anticline associated with east–west-trending growth faults and fault-assisted closures. The major growth faults appear to support hydrocarbon trapping rather than direct aquifer invasion. However, ant-tracking attributes and CT-scanned core plugs indicate short, disconnected and locally dense fracture networks within the reservoir interval, particularly around well areas and within the time interval corresponding to the N5.2 sand. The reservoir displays a blocky to cylindrical log motif, a sharp lower contact and a gradational upper contact, suggesting lateral continuity. Petrophysical and facies models indicate a sand-dominated reservoir with a net-to-gross ratio greater than 83%, negligible shale volume, and high porosity and permeability. The Dykstra–Parsons coefficient of 0.30 indicates relatively low permeability heterogeneity, while the Winland plot shows many samples with permeability above 1000 mD. Production data show early water breakthrough, increased water cut and declining oil rate after initial high production. The results suggest that fracture-enhanced vertical permeability, high reservoir quality and production-management conditions contributed to early water coning and reduced oil recovery.

Computation of the Compressional Wave (Vp) to Shear Wave (Vs) Velocity Ratio from the 2018 Mpape Earth Tremor in Nigeria

2026-07-04T07:14:13+00:00

Although Nigeria is generally considered to be located on a seismically stable part of the African plate, several earth tremors have been reported within the country, including the September 2018 Mpape event in the Federal Capital Territory, Abuja. The causes of these tremors and the related crustal and upper-mantle structure remain insufficiently constrained. This study computed the ratio of compressional wave velocity (Vp) to shear wave velocity (Vs) for the 2018 Mpape main tremor using available P- and S-wave arrival times from Nigerian seismic stations. The arrival times of regional phases, including Pg, Sg, Pn, and Sn, were obtained with Seisan software. The S-P arrival-time differences were calculated and plotted against the absolute P-wave arrival times using the Wadati-diagram approach. The Vp/Vs ratio was derived from the slope of the line of best fit using the least-squares method. The computed Vp/Vs ratio for the Mpape earth tremor was 1.76, with a root mean square value of 0.25 and a correlation coefficient of 0.999. The result suggests a relatively uniform lithology around the tremor epicentre and is consistent with the geological interpretation of the study area. The findings provide locally derived seismic parameters that may support future investigations of crustal structure, local earthquake location, and seismic-hazard assessment in Nigeria.

Fractionation-Controlled Nb–Ta Mineralization in Rare-Element LCT Pegmatites of the Lokoja Basement Complex, Nigeria

2026-07-04T12:54:28+00:00

This paper presents a geochemical and petrological assessment of niobium-tantalum-bearing pegmatites around Bakomba village, Lokoja, Kogi State, central Nigeria. Field mapping, structural measurements, thin-section petrography, and major- and trace-element geochemistry were integrated to determine emplacement style, source affinity, degree of fractionation and rare-metal mineralisation potential. The pegmatites occur as concordant flat-lying bodies and discordant dykes/veins hosted by migmatite-gneiss, Obajana gneiss and Older Granite units of the Nigerian Basement Complex. Structural measurements define dominant N-S, NW-SE and NE-SW trends, with NE-SW orientations particularly prominent, suggesting late Pan-African brittle-structure-controlled melt migration and dyke emplacement. Petrographically, the host granitoids are quartz-feldspar-biotite-rich and contain microcline and monocrystalline to polycrystalline quartz. Cross-hatched twinning, sutural contacts, undulose extinction and microfractures record crystallisation, deformation and recrystallisation. Geochemically, the biotite granite shows features compatible with an evolved, weakly to moderately peraluminous S-type affinity and a likely post-orogenic setting, with enrichment in Rb, Sn, Li and Nb relative to the gneissic host. Feldspars are low in Ta but enriched in Rb and Cs, whereas muscovite contains the strongest rare-metal signature, including Nb, Ta, Sn, Rb and Cs. The central Bakomba mica sample BM2 shows higher Ta and lower K/Rb than the northern Bakomba mica sample BM1, indicating stronger fractionation and higher Nb-Ta mineralisation potential. The data support classification of the Bakomba bodies as rare-element LCT pegmatites genetically related to evolved peraluminous granitic melts. Central Bakomba is therefore the preferred target for follow-up Nb-Ta exploration.

Tectonic Geomorphology Analysis of Nigeria Using Google Earth Engine: A Multi- province Investigation of Lineaments and Neotectonic Activity

2026-07-13T06:41:20+00:00

Nigeria's crust records a long and complex geological history, yet country-scale quantitative evaluation of its tectonic geomorphology remains limited. This study applied standardised Google Earth Engine workflows to assess lineaments and morphometric indicators across major tectonic provinces, including the Jos Plateau, Benue Trough, Cross River region, Southwestern Basement Complex and a national-scale synthesis. SRTM and ALOS digital elevation models at 30 m resolution were analysed using multi-directional hillshade, Sobel edge detection and five geomorphic indicators: lineament density, relief, terrain roughness, mountain-front sinuosity and stream offsets. The workflow extracted 2,847 lineaments and generated weighted tectonic activity maps, which were validated using 47 independently mapped geological reference points. The validation produced 41 successful matches, equivalent to 87% accuracy, with stronger performance in crystalline basement terrains than in low-relief sedimentary basins. The results distinguish three relative neotectonic provinces: higher activity in parts of the Southwestern Basement Complex and western Jos Plateau margin, moderate activity in the Benue Trough and Cross River region, and lower activity across major sedimentary basins. Dominant NNE-SSW and NE-SW structural trends suggest that inherited basement and rift-related fabrics continue to influence geomorphic expression under contemporary stress conditions. The findings provide a reproducible regional framework for tectonic geomorphology assessment in data-limited intraplate settings and may support future seismic-hazard and resource-evaluation studies.

Mean Sea Level Analysis and Coastal Inundation Mapping of Lagos State, Nigeria Using Google Earth Engine

2026-07-13T13:24:11+00:00

Lagos State is a rapidly growing coastal region where population pressure, infrastructure development and low-lying terrain increase exposure to coastal inundation. This study integrated Sentinel-1 Synthetic Aperture Radar, Shuttle Radar Topography Mission Digital Elevation Model data and Google Earth Engine processing to assess mean sea-level trend and coastal inundation vulnerability between 2010 and 2023. The analysis used simulated sea surface height data, SAR-based water detection and an elevation-based vulnerability approach to identify low-lying and high-risk zones. The sea surface height analysis indicated a relative sea-level rise rate of 3.8166 mm/year, equivalent to an estimated cumulative increase of 53.43 mm, or approximately 5.34 cm, over the study period. Terrain analysis showed that land below 5 m above mean sea level occupied approximately 1534.1 km², while the high-vulnerability zone covered approximately 1527.9 km². Seasonal water extent derived from SAR data was 667.7 km² during January–March 2023 and 653.1 km² during June–August 2023. Monthly climatology showed that sea surface height generally increased from February to August, with the highest relative flood-risk period occurring between June and October. The findings indicate that low elevation is a major control on coastal inundation vulnerability in Lagos State and highlight the need for regular monitoring, improved elevation data and integration of vulnerability mapping into coastal planning.

Hydrogeophysical Delineation of Coastal Aquifer Systems Using Electrical Resistivity Imaging in Selected Coastal Communities of the Niger Delta, Nigeria

2026-07-17T04:20:44+00:00

An integrated hydrogeophysical investigation was conducted to delineate coastal aquifer systems and assess groundwater potential in selected coastal communities of the Niger Delta, Nigeria. Ten Vertical Electrical Sounding stations and five Two-Dimensional Electrical Resistivity Tomography profiles were acquired using an ABEM Terrameter SAS 1000. Apparent resistivity data were interpreted with IPI2Win and RES2DINV software, while hydraulic parameters, Dar-Zarrouk parameters, reflection coefficient and coefficient of anisotropy were derived from the interpreted resistivity models. Four principal geoelectrical layers were identified: sandy topsoil, clay, sandy clay and freshwater-bearing sand aquifers. Aquifer resistivity ranged from 485 to 622 Ωm, and aquifer thickness varied from 52.4 to 74.6 m at depths of 25.2–30.9 m. Longitudinal conductance values of 0.62–0.76 mhos indicated moderate to good aquifer protective capacity, while transverse resistance values of 25,414–46,401 Ωm² suggested favourable transmissive conditions. Estimated hydraulic conductivity ranged from 12.5 to 18.0 m day⁻¹, with transmissivity values of 655–1,343 m² day⁻¹. Reflection coefficient values of 0.31–0.45 and coefficient of anisotropy values of 1.36–1.72 indicated moderate to very high groundwater potential. The integrated interpretation indicates that the aquifers have favourable storage and transmission characteristics for groundwater development. However, their low elevation and proximity to the Atlantic coastline require continuous monitoring and regulated abstraction to limit seawater-intrusion risk.

Geothermal Gradient, Heat Flow and Curie Point Depth as Key Indicators of Hydrocarbon Maturity in Parts of Southern Nigeria: Insights from Aeromagnetic Data

2026-07-23T10:08:53+00:00

This study evaluates the use of Curie-point depth (CPD), geothermal gradient, and heat flow as regional indicators of hydrocarbon maturity across parts of southern Nigeria using aeromagnetic data. Eight magnetic sheets covering the southeastern onshore Niger Delta, Calabar Flank, and adjoining Basement Complex were processed, and the residual magnetic field was divided into 40 overlapping spectral blocks. Radial power-spectrum analysis was used to estimate the depths to the top and centroid of magnetic sources, from which CPD, geothermal gradient, and heat flow were calculated. CPD ranges from 23.27 to 83.15 km, with a mean of 60.36 km. The geothermal gradient ranges from 6.98 to 24.93°C/km, with a mean of 10.30°C/km, while heat flow ranges from 17.44 to 62.33 mW/m², with a mean of 25.74 mW/m². Blocks 2, 4, 7, and 29 show intermediate CPDs and moderate thermal conditions that may be comparatively favourable for oil maturation. Blocks 8, 9, and 18 exhibit shallower CPDs and higher thermal parameters, suggesting more advanced maturity and possible gas-prone conditions. Blocks 19, 32, 35, and 36 display deeper CPDs and lower thermal parameters, indicating comparatively cooler and potentially under-mature conditions. The results demonstrate the value of aeromagnetic CPD analysis for regional thermal screening, while recognising that the interpretations remain indirect and require confirmation using borehole, seismic, and geochemical evidence.

GNSS-Based Monitoring of Present-Day Crustal Deformation in the Hunli Region, Eastern Himalayan Syntaxis, India

2026-07-24T09:40:57+00:00

The Eastern Himalayan Syntaxis (EHS) is one of the most tectonically active regions of the Himalayan orogen, where the Indian, Eurasian, and Burma plates interact through ongoing convergence and crustal deformation. However, geodetic observations from the eastern Arunachal Himalaya remain limited, restricting understanding of present-day tectonic processes. This study aims to monitor present-day crustal deformation in the Hunli region, Arunachal Pradesh, India, using campaign-based Global Navigation Satellite System (GNSS) observations. GNSS data collected between 2008 and 2012 were processed using the GAMIT/GLOBK software package in the International Terrestrial Reference Frame 2014 (ITRF2014), incorporating precise satellite ephemerides and International GNSS Service (IGS) products. Coordinate time-series analysis demonstrates stable station performance suitable for precise geodetic measurements. The estimated horizontal velocity of the Hunli station is 2.26 mm yr⁻¹ towards the northeast (azimuth 45.9°), with eastward and northward velocity components of 1.60 mm yr⁻¹ each. These observations provide new geodetic constraints from a sparsely monitored sector of the Eastern Himalayan Syntaxis and establish a valuable baseline dataset for monitoring present-day crustal deformation in the eastern Arunachal Himalaya. The findings improve understanding of regional crustal kinematics and provide a valuable reference for future geodetic studies, tectonic modelling, and seismic hazard assessment. The study further underscores the importance of expanding continuous and campaign-mode GNSS networks to better characterise crustal deformation and refine geodynamic models of the Eastern Himalayan Syntaxis.

Visualizing Aquifer Architecture: A Stratigraphic Approach Using VES-Derived Fence Diagrams and Section Plots

2026-07-27T14:02:55+00:00

Understanding subsurface aquifer geometry is essential for effective groundwater exploration and management, particularly in regions facing increasing water scarcity. This study uses Vertical Electrical Sounding (VES) data to visualise aquifer architecture across selected Local Government Areas (LGAs) in south-eastern Nigeria, spanning longitudes 7.00°E to 7.175°E. Section plots and pseudo fence diagrams were used to interpret stratigraphic continuity, depth variability, and the spatial distribution of aquifer intervals to depths of 300 metres. Field-based VES surveys using the Schlumberger array, combined with inversion techniques, revealed a heterogeneous aquifer system, with maximum thickness exceeding 250 metres between 7.050°E and 7.100°E, which is indicative of a depositional depocentre, and thinning towards 7.150°E, suggesting erosional or structural controls. The section plot delineated variable top and bottom depths, ranging from 50 to more than 250 metres, with the thickest interval around 7.12°E. The correlation heatmap showed strong positive relationships between thickness and bottom depth (0.95) and between thickness and resistivity (0.95), reflecting lithological and structural influences. These visualisations simulate geological cross-sections, highlighting aquifer stacking, pinch-outs, and lateral extent, and they are interpreted within a sequence-stratigraphic framework that suggests sediment aggradation, erosion, and tectonic activity. The study demonstrates that VES-derived fence diagrams are useful tools for stratigraphic profiling, providing analytical depth and communicative clarity. It also supports expanded surveys, including electrical resistivity tomography (ERT), to improve imaging resolution and strengthen groundwater-resource assessment.

Neoarchaean Stromatolitic Carbonates of the Aleshpur Formation, Shimoga Schist Belt, India: Geochemical Insights

2026-07-31T11:17:11+00:00

Neoarchaean stromatolitic carbonates preserve valuable records of early microbial ecosystems, seawater chemistry, and environmental conditions on the primordial Earth. This study investigates the stromatolitic carbonates of the Aleshpur Formation, Shimoga Schist Belt, Western Dharwar Craton, using integrated sedimentological observations, major- and trace-element geochemistry, rare-earth-element and yttrium (REE+Y) systematics, and stable carbon and oxygen isotope analyses to constrain their depositional environment and post-depositional evolution. The carbonates are characterised by high CaO and low Al₂O₃ and TiO₂ contents, indicating minimal siliciclastic contamination and preservation of primary carbonate chemistry. PAAS-normalised REE+Y patterns display positive La and Y anomalies, weak Ce anomalies, and variable Eu anomalies ranging from moderately negative to weakly positive, together with elevated Fe₂O₃ and MnO concentrations, suggesting precipitation from ferruginous Neoarchaean seawater with localised and intermittent hydrothermal influence. Stable isotope compositions exhibit a narrow range of δ¹³C values (−1.60 to +0.18‰ VPDB) and relatively depleted δ¹⁸O values (−16.82 to −13.26‰ VPDB). The coupled variation between δ¹³C and δ¹⁸O, together with the relatively narrow range of δ¹³C values and preservation of primary REE+Y signatures, indicates that carbon isotopes largely retained their primary marine dissolved inorganic carbon (DIC) signature, whereas oxygen isotopes experienced greater post-depositional modification. Integrated sedimentological and geochemical evidence indicates that the Aleshpur stromatolitic carbonates were deposited on a shallow, low-energy carbonate platform under ferruginous marine conditions, with minimal terrigenous input and episodic hydrothermal activity, thereby providing optimum conditions for microbial carbonate growth. This study provides the first comprehensive geochemical framework for the Aleshpur stromatolitic carbonates. It establishes them as a well-preserved archive of Neoarchaean ferruginous shallow-marine environments in the Western Dharwar Craton, thereby improving our understanding of early microbial carbonate formation and seawater evolution.

Structural Analysis and Hydrocarbon Prospects in the Niger Delta: 3-D Seismic Section

2026-08-06T06:43:24+00:00

This study evaluates structural controls and hydrocarbon prospectivity in a Niger Delta field using three-dimensional (3-D) seismic reflection data. The dataset comprises eight seismic volumes, including five in-lines and three cross-lines, together with a base map and check-shot data. Faults and horizons were interpreted manually from reflection discontinuities, event displacement and termination, overlapping reflections, and changes in seismic patterns across fault zones. Nine faults were mapped: seven synthetic growth faults dipping basinwards and two antithetic faults dipping landwards. Three horizons, Abbey_H1, Abbey_H2, and Abbey_H3, were delineated from reflection continuity, amplitude, strength, and configuration. Abbey_H1 is interpreted as a sand-prone interval with shale intercalations deposited in a low-energy deltaic-plain setting, whereas Abbey_H2 represents a sand-rich interval with interbedded shale deposited in a medium- to high-energy delta-front environment. Abbey_H3 is characterised by weak, low-amplitude, hummocky-to-chaotic reflections and is interpreted as gravity-driven mass-transport deposits in a deep-water slope setting. The synthetic faults trend approximately west-east, while north-south-trending faults are concentrated in the northern area. Strong reflections along fault margins suggest possible clay or shale smearing and associated sealing potential. Increasing fault throw towards the north may favour hydrocarbon retention, although the interpretation remains qualitative. The results demonstrate the value of integrating horizon mapping with structural interpretation to identify fault-dependent closures and reduce uncertainty in prospect evaluation.

Assessment of Aquifer Protective Capacity, Groundwater Vulnerability, and Heavy Metal Pollution in Gully Erosion Landscapes of Abia State, Nigeria

2026-08-06T13:38:46+00:00

Groundwater resources in gully erosion-prone areas are increasingly threatened by contaminant infiltration due to the removal of protective overburden and exposure of aquifer systems. This study assessed aquifer protective capacity, groundwater vulnerability, and heavy metal pollution in selected gully erosion landscapes of Abia State, Nigeria, using an integrated hydrogeophysical and hydrochemical approach. Measurements were obtained at twenty Vertical Electrical Sounding (VES) stations and along six Electrical Resistivity Tomography (ERT) profiles to delineate aquifer characteristics and evaluate protective capacity using Dar Zarrouk parameters. Groundwater samples were collected from twenty boreholes and analysed for physicochemical parameters and selected heavy metals using standard analytical procedures. The Heavy Metal Pollution Index (HPI), Hazard Quotient (HQ), Hazard Index (HI), Pearson correlation analysis, Principal Component Analysis (PCA), and Geographic Information System (GIS)-based spatial analysis were employed to evaluate groundwater quality and contamination risk. Aquifer resistivity ranged from 138.4 to 982.6 Ωm, whereas aquifer thickness varied between 22.6 and 72.4 m. Longitudinal conductance values ranged from 0.18 to 1.76 S, indicating aquifer protective capacities ranging from weak to good. Groundwater vulnerability assessment showed that 30.0% of the investigated locations were highly vulnerable, 45.0% were moderately vulnerable, and 25.0% exhibited low vulnerability. Iron recorded the highest concentration (0.08–1.26 mg/L), and concentrations exceeding World Health Organization guideline values for iron, lead, and cadmium were observed at several sampling locations. Heavy Metal Pollution Index values ranged from 42.8 to 156.7, with 35.0% of groundwater samples classified as highly polluted. The Hazard Index values were 2.11 for adults and 3.76 for children, indicating greater non-carcinogenic health risks among children. Pearson correlation analysis revealed strong positive relationships among electrical conductivity, total dissolved solids, and selected heavy metals, while PCA showed that the first three principal components explained 84.6% of the variance in the dataset. The findings indicate that gully erosion has reduced the natural protective capacity of aquifers and increased groundwater vulnerability to heavy metal contamination in parts of Abia State. The integration of hydrogeophysical and hydrochemical techniques was effective for groundwater resource assessment and provided valuable information for groundwater protection, environmental monitoring, and sustainable water resource management in erosion-prone regions.

Microfacies-controlled Depositional Evolution and Diagenetic Framework of the Middle–late Eocene Fulra Limestone, Kutch Basin, Western India

2026-08-07T13:27:18+00:00

The Middle–Late Eocene Fulra Limestone of the Kutch Basin represents a prominent nummulitic carbonate system developed along the western continental margin of India. Despite extensive palaeontological research in the basin, detailed microfacies-based depositional and diagenetic frameworks for this unit remain limited. This study integrates field-based facies analysis with petrographic and microfacies investigations to reconstruct the depositional evolution and diagenetic history of the Fulra Limestone. Four lithofacies and seven microfacies types were identified and correlated with Standard Microfacies (SMF 8, 9, 10, and 18), indicating deposition under conditions ranging from restricted to open marine. Grain-supported foraminiferal packstones, dominated by Nummulites and Discocyclina, reflect moderate- to high-energy environments, whereas mud-supported wackestones represent lower-energy conditions below the fair-weather wave base. The vertical facies succession reveals a systematic shallowing-upward trend, culminating in subaerial exposure marked by karstification and increased insoluble residue. Petrographic analysis indicates a multistage diagenetic evolution involving early marine micritisation and cementation, followed by compaction, neomorphism, dissolution, and localised dolomitisation. These processes significantly modified the primary texture and porosity. The Fulra Limestone is interpreted as a low-gradient carbonate shelf system in which sedimentation was controlled by hydrodynamic energy, relative sea-level fluctuations, and ecological constraints on larger benthic foraminifera. This study provides a refined depositional and diagenetic model for Eocene nummulitic carbonates in peri-cratonic rift settings and contributes to a better understanding of their stratigraphic and reservoir significance.

Petrophysical Assessment of the Reservoir Intervals Within the Gombe and Gongila Formations, KY Field Chad Basin, Northeastern Nigeria

2026-08-10T13:03:25+00:00

This study presents a comprehensive petrophysical evaluation of reservoir pay zones within the Gombe and Gongila formations across three wells in the Chad Basin, focusing on key reservoir parameters, including porosity, permeability, water saturation, and lithology (volume of shale), to assess reservoir quality and hydrocarbon potential. The analysis used triple-combo well logs (gamma-ray, neutron, density, and resistivity) from three wells: XY-1, XY-2, and XY-3. Petrophysical evaluation was conducted using Schlumberger Techlog software to define zones, establish correlations, and assess reservoir properties. The results show distinct variations in reservoir properties across both formations, with water saturation in the Gombe and Gongila formations averaging 0.34 m³/m³ and 0.25 m³/m³ (XY-1), 0.30 m³/m³ and 0.32 m³/m³ (XY-2), and 0.51 m³/m³ and 0.31 m³/m³ (XY-3), respectively. Average porosity values were 0.30 m³/m³ and 0.23 m³/m³ (XY-1), 0.29 m³/m³ and 0.26 m³/m³ (XY-2), and 0.31 m³/m³ and 0.10 m³/m³ (XY-3), while shale-volume measurements averaged 0.21 and 0.25 (XY-1), 0.23 and 0.23 (XY-2), and 0.22 and 0.25 (XY-3). Pay-zone thickness varied substantially, measuring 117.3 m and 20.4 m (XY-1), 42.3 m and 22 m (XY-2), and 337 m and 129.4 m (XY-3) for the Gombe and Gongila formations, respectively. Overall, the Gombe Formation demonstrated superior reservoir properties and greater pay-zone thickness, with thickness generally increasing towards well XY-3. These findings provide insight into the reservoir potential of both formations within the Chad Basin and support ongoing exploration in this underexplored frontier basin.

Petrophysical Characterization and Reservoir Quality Assessment of Field "D" in the Central Niger Delta Basin, Nigeria: An Integrated Well Log Analysis

2026-08-11T11:52:22+00:00

This study presents a comprehensive petrophysical characterisation and reservoir quality assessment of Field "D", located in the Central Niger Delta Basin, Nigeria, utilising well log data from three exploratory wells (OTIG 2, OTIG 7, and OTIG 9). Rigorous data quality control, calibration verification, and uncertainty propagation analyses were integrated into the workflow to ensure the reliability of computed petrophysical parameters. The study integrated gamma-ray, resistivity, density, and neutron log responses to evaluate key reservoir properties, including porosity, permeability, shale volume, fluid saturation, net-to-gross ratio, and transmissivity across three hydrocarbon-bearing sandstone reservoirs (Reservoirs A, B, and C). Sensitivity analyses and cross-validation against regional benchmarks were performed to validate the empirical models employed. The results indicate that the reservoirs exhibit good to excellent reservoir quality, with average porosity values ranging from 14% to 20%, permeability values exceeding 100 millidarcies (md), and hydrocarbon saturation values between 48% and 70%. The bulk volume water (BVW) analysis suggests that the reservoirs are at or near irreducible water saturation, indicating good hydrocarbon producibility. Stratigraphic correlation revealed that Reservoirs A, B, and C in well OTIG 2 may represent a continuous sand body, supported by consistent petrophysical parameters and similar depth intervals. The inherent limitations of the well log dataset, including depth-dependent resolution constraints and the absence of core calibration, are explicitly discussed to contextualize the uncertainty bounds of the interpreted results. The findings indicate that Field "D" possesses significant hydrocarbon accumulation potential, with reservoir parameters comparable to other productive fields in the Niger Delta. This study contributes to the growing body of knowledge on integrated well log interpretation techniques for reservoir characterisation in the Niger Delta Basin and provides valuable insights for reservoir management and development planning.

Ground Displacement Associated with the September 2024 Mpape Tremor, Abuja, Nigeria: A Sentinel-1 DInSAR Analysis

2026-08-14T08:15:19+00:00

On 17 September 2024, a moderate tremor of magnitude Mw 3.0 was reported in the Mpape area of Abuja, Nigeria, raising concern about ground stability in a rapidly expanding urban environment. This study applied Sentinel-1 C-band Differential Interferometric Synthetic Aperture Radar (DInSAR) to examine line-of-sight (LOS) ground displacement associated with the event. Two Sentinel-1A single-look complex images acquired before and after the tremor, on 29 August and 10 October 2024, were processed through a standard workflow involving orbit correction, coregistration, interferogram generation, topographic phase removal, Goldstein filtering, phase unwrapping and terrain correction. The results showed high interferometric coherence in built-up areas, with values exceeding 0.96, whereas vegetated and steep-slope areas had lower coherence and were excluded from reliable displacement interpretation. The maximum LOS displacement near the reported epicentral zone was estimated at 0.89 ± 0.3 cm, while the mean deformation of reliable pixels remained minor. The deformation pattern was localized and limited in spatial extent, with no evidence of coherent surface rupture or widespread hazardous subsidence. The pattern is consistent with a small, shallow seismic source; however, the use of only two SAR acquisitions limits the separation of coseismic, post-seismic, atmospheric, seasonal and anthropogenic effects. Continued InSAR monitoring supported by ground-based seismic and geodetic observations is recommended for Abuja and nearby basement-complex terrains.

Radiological Evaluation of Background Ionizing Radiation of Some Selected Solid Mineral Mining Sites in Kogi State, Nigeria

2026-08-18T06:34:08+00:00

This study evaluated the background ionising radiation (BIR) levels of some selected solid mineral mining sites in Kogi State. The BIR measurements were taken using a well-calibrated radiation meter (Digilert 200), placed at an elevation of 1.0m above ground level, and a Global Positioning System (GPS) to determine the geographical locations. Each measurement was repeated three times, with approximately 5-10 minutes spent at each measuring point. The mean exposure dose rates obtained were 0.027, 0.021, 0.055, 0.046, 0.024, 0.020, and 0.026 respectively, in mR/hr. The values are higher than the recommended safe limit of 0.013mR/h. The mean Absorbed Dose Rates obtained are 235.3, 186.4, 482.3, 272.8, 209.0, 178.4 and 225.1 respectively, in nGy/hr. The values are all higher than the recommended safe limit of 84.0nGy/hr. The mean values obtained for AEDE are 0.386, 0.306, 0.769, 0.485, 0.343, 0.293 and 0.370 respectively, in mSV/yr. The mean values obtained for ELCR are 1.35 x 10^-3, 1.07 x10^-3, 2.75 x10^-3, 1.57 x10^-3, 1.20 x10^-3, 1.02 x10^-3 and 1.29 x 10^-3respectively. The values are higher than the ICRP standard of 0.29 x10^-3, indicating a detrimental cancer risk for residents of the study area. The results obtained from this research established significantly elevated radiation levels, indicating a possible increase in radiation-induced injuries and long-term cancer among inhabitants. The findings will contribute to baseline data on radiological safety, support risk assessment and the development of regulatory policies, and support a sustainable environmental monitoring structure for mining areas in Kogi State.

Petrography and Geochemical Characteristics of Aplites from Kyrdem Granitoids, Meghalaya Plateau, Northeast India

2026-08-19T07:32:32+00:00

This study investigates aplites associated with the Kyrdem granitoids of the Meghalaya Plateau, Northeast India, using field observations, petrography, and whole-rock geochemical analyses. The aplites are fine-grained, leucocratic rocks that occur as small stocks, narrow veins, or minor dykes and represent late-emplaced products of a silica-rich residual melt associated with the host granitoids. Their mineral assemblage consists predominantly of quartz, plagioclase, and alkali feldspar, with biotite, zircon, apatite, and opaque minerals as accessory phases. Whole-rock geochemistry indicates high silica contents (average 68.78 wt.%), a granitic composition, calc-alkaline affinity, and a peraluminous character. Harker variation trends show decreasing Fe₂O₃, MgO, CaO, TiO₂, and P₂O₅ with increasing SiO₂, indicating progressive fractionation involving plagioclase, apatite, titanite, biotite, and hornblende. Rare earth element and trace element patterns indicate late-stage granitic differentiates derived from subduction-modified magmas that evolved through extensive fractional crystallisation with minor crustal assimilation. The aplites have an average total REE concentration of approximately 637.37 ppm and display strong LREE fractionation. Their moderate Rb/Sr ratios (0.40–4.02) and variable Nb/Ta ratios (13.77–39.38) indicate crystallisation from moderately evolved felsic melts with heterogeneous Nb–Ta behaviour. Tectonic discrimination suggests a predominantly late-orogenic affinity with a minor syn-collisional component. These integrated observations provide a petrographic and geochemical framework for understanding late-stage felsic magmatism in the Shillong–Meghalaya Plateau.

Comparative Evaluation of Robust Hybrid and Modulated RMS Seismic Attributes for Reflector Enhancement and Spike Suppression Using Two Synthetic Datasets and Six Real Seismic Lines

2026-08-21T08:57:23+00:00

Conventional root-mean-square amplitude is widely used to represent local seismic reflection energy, but its quadratic dependence on amplitude makes it susceptible to impulsive spikes, amplitude extremes, and spatial broadening of high-energy responses. This study develops and evaluates three interpretable RMS-related seismic attributes that introduce robustness at different stages of local energy estimation: Modulated RMS, Despike-aware Modulated RMS, and a Weighted Hybrid estimator. The Modulated RMS attribute preserves conventional RMS as its baseline while applying a bounded central–surround energy-contrast correction. The Despike-aware formulation applies median- and median-absolute-deviation-based amplitude control before evaluating the same modulation. The Weighted Hybrid estimator combines Huber-weighted quadratic energy with a Huber-weighted logarithmic amplitude measure through an adjustable blending coefficient. The novelty lies not in the individual use of RMS, Huber weighting, median-based statistics, or logarithmic averaging, but in their specific integration into complementary seismic-attribute formulations with distinct operational purposes. The methods are evaluated against conventional RMS using two synthetic datasets with clean reference sections and six field seismic datasets representing different structural and noise conditions. The results demonstrate condition-dependent behaviour: Modulated RMS provides conservative local enhancement, the despike-aware formulation is most relevant to impulsive contamination, and the Weighted Hybrid estimator provides stronger control of amplitude extremes and background responses. No method is universally superior across all datasets and evaluation criteria. The proposed framework therefore provides a set of complementary attribute options for reflector enhancement, spike suppression, and structurally informed seismic interpretation.

Groundwater Potential Zones in the Koulikoro District, Mali: Delineation Using GIS, Remote Sensing and Multi-Criteria Analysis

2026-08-21T10:36:46+00:00

Background: Groundwater development in Precambrian basement terrains is constrained by the discontinuous and heterogeneous distribution of productive aquifers.

Aim: This study aimed to map potential groundwater zones in the Koulikoro district (Mali) by integrating Geographic Information Systems (GIS), remote sensing, and Multi-Criteria Analysis (MCA), and to validate the resulting map using borehole production data.

Study Design: A spatial analysis using a weighted multi-criteria overlay combined with validation against field borehole data.

Place and Duration of Study: Koulikoro district, Koulikoro Region, Mali. The data covered the period 1992–2022.

Methodology: Seven hydrogeological criteria—slope, geology, fracture density, drainage density, weathering thickness, rainfall, and land use—were derived from Sentinel-2 imagery (10 m), a Digital Elevation Model (30 m, SRTM/NASA), geological maps, and the national borehole database (SIGMA). Each criterion was reclassified into five suitability levels and weighted using Saaty's Analytic Hierarchy Process (AHP). A weighted overlay in ArcGIS produced the groundwater potential map.

Results: About 68% of the study area (3,769 km² of 5,510 km²) shows high or moderate potential, with 30% classified as 'high' and 38% as 'moderate'. The remaining area is classified as 'low' (4%) or 'very low' (28%). Validation against the yields of 214 boreholes shows an overall agreement of 71%, with 89% of boreholes in the 'very good' yield class occurring within 'high' potential zones and 56% of boreholes in the 'low' yield class occurring within 'very low' zones. The association is highly significant (chi-square = 289.4, df = 9, p < 0.001; Cohen's kappa = 0.58). The AHP consistency ratio (CR = 0.082 < 0.10) indicates acceptable consistency among the pairwise judgements. The map expresses relative groundwater prospectivity rather than groundwater volume or sustainable yield.

Conclusion: The integrated GIS, remote sensing, and MCA approach identifies priority zones for further groundwater investigation in the Koulikoro district and provides a cost-effective screening framework for sustainable groundwater resource management in similar Precambrian basement settings.

Drivers of Agroforestry Tree Adaptation among Households Bordering Mukura Forest, Rutsiro District, Rwanda

2026-08-21T10:43:34+00:00

Aims: To examine how households living near Mukura Forest in Rutsiro District, Rwanda, have taken up agroforestry trees on their farms, and specifically to establish the prevailing level of uptake, the leading factors behind it, and the strength of association between those factors and uptake.

Study Design: A mixed-methods study combining descriptive and explanatory components, drawing on both quantitative and qualitative evidence.

Place and Duration of Study: Households situated within a 2.5 km radius of Mukura Forest, across Mukura, Rusebeya, and Mushubati sectors of Rutsiro District, Western Province, Rwanda; the agroforestry practices reviewed covered the period 2019–2024.

Methodology: A total of 372 household heads were sampled from a population of 5,185 households using Yamane's (1967) formula, combined with proportionate stratified sampling across sectors and cells and simple random selection of respondents within each cell. Structured questionnaires containing five-point Likert items, key informant interviews, on-farm observations, and secondary documentation provided the data. Quantitative data were analysed in SPSS version 28 using descriptive statistics, Pearson correlation, and multiple linear regression, while interview data were examined thematically.

Results: Households reported a relatively high overall level of agroforestry uptake (composite mean = 3.99, SD = 0.91). Among the factors examined, incentives carried the greatest weight (mean = 4.19), followed by community participation (mean = 4.05) and training (mean = 3.95), each showing a clear positive association with uptake. A Pearson correlation confirmed a strong, statistically significant relationship between these combined factors and the level of uptake (r = 0.876, P = .000), and regression analysis showed that they jointly accounted for 76.7% of the variance observed (R² = 0.767, F(1, 370) = 1217.121, P = .000). Households most often pointed to an insufficient supply of seedlings, small plot sizes, limited extension coverage, and concerns about competition between trees and crops as the chief obstacles to wider uptake.

Conclusion: Households around Mukura Forest are broadly aware of the benefits of agroforestry, yet incentives, training, and community involvement remain the strongest factors for translating that awareness into planting, while limited land and input supply continue to limit the extent of uptake. Reinforcing seedling delivery systems, farmer training, and community-anchored programmes would help translate existing awareness into fuller adaptation and stronger outcomes for both livelihoods and forest conservation.

Waste Management Practices, Ecosystem Resilience and Sustainable Development in Artisanal and Small-scale Mining Communities: Evidence from Gakenke District, Rwanda

2026-08-21T12:07:00+00:00

Aims: This study aimed to assess the association between waste management practices and ecosystem resilience and sustainable development outcomes among artisanal and small-scale mining communities in Gakenke District, Northern Rwanda.

Study Design: A mixed-methods research design combining quantitative and qualitative approaches was applied.

Place and Duration of Study: The study was conducted in artisanal and other small-scale mining sites in Gakenke District, Northern Province, Rwanda, between 2025 and 2026.

Methodology: The study used a mixed-methods design combining descriptive and explanatory approaches, surveying 370 respondents selected via purposive and stratified random sampling. Data collection tools included a 45-item structured questionnaire, 12 key informant interviews, field observations, and laboratory water quality analysis (pH, Fe, Cr, Zn) from three mining-affected rivers. Data were analysed using SPSS v28 through descriptive statistics, correlation, and regression, alongside a comparison of laboratory results with Rwanda's RS 110:2017 standards. Reliability was assessed through piloting and Cronbach's alpha coefficients, which are reported for each multi-item scale, while validity was established through triangulation and expert review.

Results: Waste classification and sorting was the most commonly reported practice (77.0%; mean = 4.20), whereas environmental monitoring and reporting was the least implemented (59.5%; mean = 3.85), followed by progressive site rehabilitation (63.5%; mean = 3.92). Waste management practices showed a significant positive relationship with ecosystem resilience and sustainable development outcomes (r = 0.666, p < 0.001) and explained 44.4% of the variation in resilience indicators (R² = 0.444; β = 0.592, p < 0.001). Laboratory results from a single sampling round at three sites revealed elevated metal concentrations in mining-affected water resources, with iron concentrations ranging from 7.1 to 21.2 mg/L and chromium concentrations from 0.215 to 0.78 mg/L, exceeding Rwanda's National Standards (RS 110:2017), whereas pH and zinc concentrations remained within permissible limits.

Conclusion: The findings indicate that inadequate waste containment, limited environmental monitoring, and weak rehabilitation practices are associated with ecosystem degradation and threaten sustainable development in artisanal and small-scale mining areas. Strengthening mining waste management systems, environmental monitoring, miner training, and post-mining rehabilitation programmes is essential for improving ecosystem resilience and promoting sustainable mining practices in Rwanda.

Assessment of the Impact of Flood Disasters on Socioeconomic Livelihoods in Nyamagabe District, Rwanda (2010–2025)

2026-08-21T12:19:34+00:00

Aims: To assess the impact of flood disasters on the socioeconomic livelihoods of households in Nyamagabe District, Rwanda, between 2010 and 2025, and to analyse the relationship between flood exposure, government/institutional response, and livelihood outcomes.

Study Design: A descriptive-correlational, mixed-methods design combining quantitative household survey data with qualitative key-informant insights.

Place and Duration of Study: Nyamagabe District, Southern Province, Rwanda, covering the period 2010–2025.

Methodology: A census of 325 respondents was used, comprising 204 officially recorded flood-affected households, 12 district-level land office employees, 17 sector land officers, and 92 cell socioeconomic development officers. Data were collected through structured questionnaires (five-point Likert-scale items), key-informant interviews, focus group discussions, document review, and GIS-based spatial analysis (ArcGIS/QGIS) to map flood-prone zones. Quantitative data were analysed using descriptive statistics, Pearson correlation, and multiple linear regression in SPSS; qualitative data were analysed thematically and triangulated with the quantitative findings.

Results: Flood events increased from 3 in 2010 to 10 in 2025; affected households rose from 110 to 204; and damaged cropland expanded from 620 to 3,200 hectares. Most respondents (64.0%) reported severe negative livelihood impacts, with 81.5% experiencing income loss and 85.5% reporting crop destruction. Regression analysis identified flood frequency (β = 0.304) and flood extent (β = 0.320) as the strongest predictors of livelihood deterioration (R² = 0.405, p < 0.001). Early warning systems significantly improved livelihood outcomes, whereas post-flood recovery support and disaster management plans showed no significant effect.

Conclusion: Recurrent flooding has substantially eroded household livelihoods in Nyamagabe District over the study period. Strengthening early warning systems, flood-control infrastructure, recovery programmes, and livelihood diversification is recommended to enhance community resilience against recurrent flooding.

Integrated Sedimentology, Organic Geochemistry, and Depositional Environment of the Ogwashi–ASABA Formation at Mgbiligba Spring, Southern Nigeria

2026-08-22T07:10:44+00:00

Despite the hydrocarbon significance of the Ogwashi–Asaba Formation in the Niger Delta Basin, integrated sedimentological and organic geochemical investigations of the Mgbiligba Spring exposure remain limited, resulting in an incomplete understanding of its depositional history and petroleum source-rock potential. This study integrates sedimentological, micropaleontological, and organic geochemical analyses to reconstruct the depositional environment and evaluate the hydrocarbon generation potential of the Ogwashi–Asaba Formation exposed at Mgbiligba Spring, southern Nigeria. Granulometric analysis of the sandstone and conglomerate facies indicates deposition under predominantly continental fluvial-to-deltaic conditions, characterised by moderate sediment maturity and variable depositional energy. The occurrence of benthic foraminifera, including Ammobaculites, Fursenkoina, and Anomalina, within shale intervals provides evidence of intermittent shallow-marine incursions, suggesting deposition within a transitional marginal-marine setting. Total Organic Carbon (TOC) values range from 1.36% in lignite to 1.66–3.71% in shale, indicating fair to good organic-matter enrichment and appreciable source-rock potential. Organic petrographic analysis reveals the dominance of huminite macerals, with subordinate liptinite and inertinite, reflecting organic-matter accumulation in humid, waterlogged swamp environments. The organic matter is interpreted as predominantly Type II/III kerogen, indicating mixed terrestrial and marine organic inputs with the potential to generate oil and gas where sufficient thermal maturity is attained. These findings provide new insights into the depositional evolution of the Ogwashi–Asaba Formation at Mgbiligba Spring and contribute to an improved evaluation of its petroleum system and hydrocarbon exploration potential within the Niger Delta Basin.

The Turonian Marine Incursion and the Trans-Saharan Seaway: A Critical Synthesis of the Nigerian Benue Trough Record

2026-08-08T09:41:09+00:00

The Benue Trough of Nigeria preserves one of the most extensively documented onshore records of the Cenomanian–Turonian marine transgression that is widely held to have linked the South Atlantic and the Tethys Sea across the West African craton, an episode commonly termed the Trans-Saharan Seaway. Because the trough exposes marine and paralic strata along an axis that crosses several structurally distinct sub-basins, it offers an opportunity to examine how a regional rift architecture governed the entry, timing and biotic character of a globally significant sea-level event. This review synthesises the tectonic, stratigraphic, biostratigraphic and geochemical literature on the Turonian incursion in the Benue Trough, with the aim of establishing which conclusions are well supported, which remain contested, and where the regional record does or does not align with the global expression of the Cenomanian–Turonian boundary event, including the associated Oceanic Anoxic Event 2. Evidence is drawn from studies of the trough's wrench-related and extensional tectonic framework, from formation-level stratigraphic and sedimentological descriptions across the Yola, Gongola, Middle and Southern sub-basins, from ammonite, echinoid, ostracod and palynological biostratigraphy used to date and correlate the transgressive interval, and from organic-geochemical studies of the associated black shales and their petroleum significance. The synthesis indicates strong convergence on a latest Cenomanian to early Turonian onset of marine flooding and on the broad lithostratigraphic expression of the event, but persistent disagreement over the precise pathway, duration and directionality of the connection, over the reliability of foraminiferal and lithological correlation across sub-basins, and over how closely the regional organic-carbon record tracks the global Oceanic Anoxic Event 2 signal. Methodological constraints, including uneven outcrop access, reliance on a small number of historically collected faunal sections, and limited high-resolution geochemical sampling, are identified as the principal sources of continuing uncertainty. The review closes by identifying research priorities capable of resolving these disagreements and by situating the Benue Trough within the broader family of Cretaceous trans-continental seaways.