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

Alawode Mujeedah Kehinde — 2026-06-10

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

A. O. Jayeola — 2026-06-13

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

G. Satishkumar — 2026-06-15

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

Akpaneno, Aniefiok Francis — 2026-06-26

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

Jeremiah Efosa Isimaronkhae — 2026-06-27

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

L. C. Agim — 2026-06-27

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

E. E. Onuchukwu — 2026-07-02

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

Prince Suka Momta — 2026-07-02

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

Umar A. Kadiri — 2026-07-04

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

O. V. Adeyemi — 2026-07-04

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

Lungfa Collins WUYEP — 2026-07-13

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

Lungfa Collins Wuyep — 2026-07-13

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.