Browsing by Author "Anuda, G.K."

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    Basement morphology of the middle Benue Trough, Nigeria, revealed from analysis of high-resolution aeromagnetic data using grid-based operator methods
    (Department of Geology and Minning, Nasarawa State University Keffi, 2020-03-05) Anuda, G.K.; Stephenson, Randell A.; Ofoegbu, Charles O.; Obrike, Stephen E.
    The middle Benue Trough is, the central segment of the Benue Trough, an elongate large intracratonic, Cretaceous to Palaeogene rift basin in Nigeria. This study provides new information about the depth to basement (sediment thickness), basement morphology and tectonics of the middle Benue Trough region through detailed analysis and interpretation of preconditioned high-resolution aeromagnetic data using three grid-based semi- automated depth-estimation methods. Integration of results reveals that the middle Benue Trough region is a moderate to deep, fault bounded rift basin with a maximum sediment thickness (basin fill) of about 6300 m. There are seven deep (> ~2500 m) sedimentary sub-basins and several elongated shallow (< ~1800 m) basement ridges. These sub-basins and basement ridges exhibit dominant NE-SW tectonic trends. Previously mapped magmatic bodies in the axial region of the Trough occur at depths less than about 1000 m. Most of the imaged subsurface features were previously unknown. Subsurface crustal basement structures show trends predominantly NE-SW, ENE-WSW, NNE-SSW and NW-SE and these generally reflect variations in pre-existing crustal basement structural trends in the area, superimposed by the effects of the regional tectonic stress fields responsible for the Trough's tectonic evolution in the Cretaceous – Palaeogene. The implication of the results in regards to hydrocarbon exploration, particularly when combined with published field geological and organic geochemical studies, is that the middle Benue Trough region is more likely to have moderate to low oil prospects and high gas prospects.
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    Compositional Characteristics and Industrial Assessment of the Asu River Group Shale in Mpu Area, Southeastern Nigeria
    (Department of Geology and Minning, Nasarawa State University Keffi, 2012-03-08) Obrike, Stephen E.; Onyeobi, T.U.S.; Anuda, G.K.; Osadebe, C.C.
    Compositional and physical characteristics of the shale from Mpu, south-eastern Nigeria, were assessed to evaluate their potential as industrial raw materials. The mineralogical determination by x-ray diffraction (XRD) of the shale, indicate kaolinite as the major clay mineral with diffused peaks of illite and smectite, with quartz as the non-clay mineral. Chemical analysis of the samples reveals the predominance of SiO2 (58.62- 59.80) and Al2O3 (21.23- 22.10) with a silica/alumina ratio of 2.51.The shale is also characterized by significant Fe2O3 (1.62 - 3.68), TiO2 (1.48 - 1.56), K2O (1.64 - 1.78) values, while CaO, MgO, Na2O, MnO and P2O5 have individual values < 1%. Samples from the study area are essentially made up of clay fractions (<65µm) above 70%, some of the physical parameters of the shale specimens include linear shrinkage (4.80-5.20), plastic limit (22.0-27.0), liquid limit (53.0- 58.0), plasticity index (28.0-34.0) and loss on ignition (9.50-9.80) values. Mineralogical and chemical compositions suggest that the shale deposit could be exploited for ceramics, paint, pottery and refractory industries.
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    Effects of Landuse Activities on Groundwater Suitability for Irrigation Purposes in Lafia Municipal, North Central Nigeria
    (Department of Geology and Minning, Nasarawa State University Keffi, 2019-03-08) Aleku, L.D.; Obrike, Stephen E.; Anuda, G.K.; Umbugadu, A.A.
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    Engineered slope failure susceptibility modelling using high spatial resolution geospatial data
    (Department of Geology and Minning, Nasarawa State University Keffi, 2022-08-08) Obrike, Stephen E.; Barr, Stuart L.; Miller, Pauline E.; Anuda, G.K.
    Given the increased hazards faced by transport corridors such as climate induced extreme weather, it is essential that local spatial hotspots of potential landslide susceptibility can be recognised. In this research, an evidential reasoning multi-source geospatial integration approach for the broad-scale recognition and prediction of landslide susceptibility in transport cor- ridors was developed. Airborne laser scanning and Ordnance Survey DTM data is used to derive slope stability parameters, while Compact Airborne Spectrographic Imager (CASI) imagery and existing national scale digital map datasets are used to characterise the spatial variability of land cover, land use and soil type. A novel approach to characterisation of soil moisture distribution within transport corridors was developed that incorporates the effects of the catchment contribution to local zones of moisture concentration in earthworks. The derived topographic and land use properties are integrated within the evidential reasoning approach to characterise numeric measures of belief, disbelief and uncertainty regarding slope instabil- ity spatially within the transport corridor. The model highlighted the importance of slope, concave curvature and permeable soils with variable intercalations accounting for over 80% of slope instability and an overall predictive capability of 77.75% based on independent validation dataset.
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    GEOCHEMICAL EVALUATION OF GROUNDWATER FROM HAND-DUG WELLS IN KUDENDA AND ITS ENVIRONS, KADUNA STATE, NORTHCENTRAL NIGERIA
    (Department of Geology and Minning, Nasarawa State University Keffi, 2010-11-11) Anuda, G.K.; Obrike, Stephen E.; Iyakwari, S.; Onuba, L.N.; Ikpokonte, A.E.
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    Groundwater Investigation Across the Crystalline Basement Rocks in Rogo Area, Kano State Northern Nigeria, Using Resistivity Methods
    (Department of Geology and Mining, Nasarawa State University Keffi., 2021-03-06) Anuda, G.K.; Obrike, Stephen E.; Ofoegbu, Charles O.
    One-dimensional (1D) resistivity sounding (VES) and two-dimensional (2D) resistivity imaging methods were employed in groundwater investigation in order to delineate potential aquifers and estimate their transmissivities in Rogo area. Main basement rock units in the area are granites and schistose quartzite rocks of Precambrian to Lower Paleozoic age. Twelve resistivity soundings (VES) were carried out across the area using Schlumberger electrode configuration. The field resistivity sounding data obtained were interpreted with partial curve matching approach and 1D inversion algorithm, IPI2Win. The 2D resistivity imaging survey was conducted along two traverses employing dipole-dipole electrode configuration and the resistivity data acquired were subjected to finite element method modelling using DIPRO inversion algorithm to generate a geologically realistic, 2D subsurface geological model. Three to five geoelectrical layers, as well as weathered bedrock (saprolite) and fractured bedrock (saprock) aquifers were delineated. Seven resistivity sounding curve types (namely H, HA, HK, KH, QH, HKH and KQH) were also identified with the H and HA types being the dominant curve types. Anisotropy coefficient (λ) values ranged from 1.03 to 2.65 with a mean of 1.31. Aquifer transmissivity computed for the weathered bedrock aquifer units varied from 16.01 to 53.3 m /day, with an average value of 30.91 m /day. The study revealed that the Rogo area has moderately high aquifer transmissivity and hence generally exhibits good groundwater potentials.
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    Hydro-geochemical characterization and water quality appraisal of groundwater in areas adjoining primordial landfills in the Maastrichtian Lafia Formation, Middle Benue Trough
    (Department of Geology and Minning, Nasarawa State University Keffi, 2012-07-06) Obrike, Stephen E.; Aleku, L.D.; Anuda, G.K.
    This study assessed the groundwater quality in areas adjoining primordial landfills in Lafia town and its suitability for drinking purposes. Physico-chemical properties of twenty groundwater samples collected from boreholes, unlined and lined hand-dug wells at twenty different locations around three dumpsites were analysed for the appraisal of the water quality. Results of measured physical parameters show pH values in the range of 5.13–7.30, electrical conductivity (EC) values as between 89 and 7754 µS/cm and total dissolved solids (TDS) values that ranges from 59.63 to 5195 mg/L. The major cation and anions have mean concentrations in the order Ca2+ > Na+ > K+ > Mg2+ and SO42− > HCO3− > Cl− > CO3−. The Piper plot reveals three dominant water types (Ca–Cl–SO4, Ca–Na–HCO3−, and Na–Cl–SO4). Heavy metal pollution assessment reveals relatively higher modified heavy metal index (m-HMI) values for wells of close proximity to the landfills. The water quality index (WQI) classification reveals 35% of the groundwater sampled locations have water categorized as unsuitable for drinking purposes, 30% of the groundwater samples categorized as very poor and 25% of the groundwater samples classified as poor. While groundwater categorized as good to excellent constituted only 10% of the total groundwater samples analysed.
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    Hydrochemical Analysis and Evaluation of Water Quality in Angwan Jeba and its Environs, Nasarawa state, Northcentral Nigeria
    (Department of Geology and Minning, Nasarawa State University Keffi, 2011-03-08) Anuda, G.K.; Obrike, Stephen E.; Onuba, L.N.; Ikpokonte, A.E.
    Angwan Jeba and its environs lies within the Basement Complex of northcentral Nigeria and is underlain by migmatitic gneiss, biotite gneiss, biotite schist, muscovite schist and older granites with minor intrusions of pegmatite and quartz veins. The study involved the hydrochemical characterisation of waters of the area to ascertain their chemistry, quality and suitability for domestic, livestock and irrigation purposes. A total of eight hand-dug wells, four hand-pump boreholes, one stream and two rivers water samples were analysed for their cations and anions. Physical parameters such as temperature, pH, Electrical Conductivity (EC) and Total Dissolved Solids (TDS) were measured in the field. Results of the analysed chemical (cations and anions) parameters ranged as follows: Ca2+ (9.4-36.1 mg L"1), Mg2+(3.8-11.7 mg L-1),Na+ (17.64- 41.5 mg L-1), K+ (4.36-18.14 mg L“1), Fe (0.08-3.0 mg L“1), Cu (<0.01 -0.99 mg L“1), HCO3_ (84.08-134 mg L"1), Cl(37.3-49.79 mg L "1), SO42" (13.2-23.4 mg L ') and N O ) (1 - 0 .9 6 mg The Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Electrical Conductivity (EC) and Exchangeable Sodium Ratio (ESR) values variedbetweenO.73-l .59, -1.015-0.633meqL-1 , 159-450 pS cm ,' ando.333-1.187, respectively. Evaluation of the results revealed that the waters are fresh ( 3 0 ؛ T D S 3 0 4 mg L ') , soft to moderately hard (39.1 TH<128.85 mg L ,'), slightly acidic to slightly alkaline (6.85
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    Hydrogeophysical investigation and estimation of groundwater potentials of the Lower Palaeozoic to Precambrian crystalline basement rocks in Keffi area, north-central Nigeria, using resistivity methods
    (Department of Geology and Minning, Nasarawa State University Keffi, 2012-03-08) Anuda, G.K.; Essien, B.I.; Obrike, Stephen E.
    The use of resistivity sounding and two-dimensional (2-D) resistivity imaging was investigated with the aim of delineating and estimating the groundwater potential in Keffi area. Rock types identified are mainly gneisses and granites. Twenty-five resistivity soundings employing the Schlumberger electrode array were conducted across the area. Resistivity sounding data obtained were interpreted using partial curve matching approach and 1-D inversion algorithm, RESIST ver- sion 1.0. The 2-D resistivity imaging was also carried out along two traverses using dipole–dipole array, and the data obtained were subjected to finite element method modeling using DIPRO inversion algorithm to produce a two-dimensional subsurface geological model. Interpretation of results showed three to four geoelectrical layers. Layer thickness values were generally less than 2 m for collapsed zone, and ranged from 5 to 30 m for weathered bedrock (saprolite). Two major aquifer units, namely weathered bedrock (saprolite) aquifer and frac- tured bedrock (saprock) aquifer, have been delineated with the latter usually occurring beneath the former in most areas. Aquifer potentials in the area were estimated using simple schemes that involved the use of three geoelectrical parameters, namely: depth to fresh bedrock, weathered bedrock (saprolite) resistivity and fractured bedrock (saprock) resistivity. The as- sessment delineated the area into prospective high, medium and low groundwater potential zones.
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    Lineament analysis and interpretation for assessement of groundwater potential ofWamba and environs, Nassarawa state. Northcentral Nigeria
    (Department of Geology and Minning, Nasarawa State University Keffi, 2011-02-02) Anuda, G.K.; Obrike, Stephen E.; Iyakwari, Shekwoyandu; Onuba, L.N.
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    NITRATE CONTAMINATION IN GROUNDWATER AROUND KEFFI TOWN, NORTHCENTRAL NIGERIA
    (Department of Geology and Minning, Nasarawa State University Keffi, 2011-08-08) Obrike, Stephen E.; Anuda, G.K.; Iyakwari, Shekwoyandu; Osadebe, C.C.
    Ten (10) vertical electrical soundings (VES) were carried out in the study area, the field data obtained were then interpreted using partial curve matching and a 1-D inversion algorithm. Resistivity results indicate the presence of top soil (<300 ohm- m), weathered basement (100 to 150 ohm-m) and fractured basement (<3000 ohm-m). The thickness of the topsoil is generally less than 2m while the weathered basement varies from 5m to 30m. Fifteen (15) groundwater samples were collected from different locations across the Keffi area and analysed for their NO3-N concentration. Groundwater sampling were restricted to well-covered shallow hand-dug wells (SHW), medium depth hand pumps (MHP) and motorised boreholes (DMBH). In all the groundwater samples analysed, 10.5% of them exhibited NO3-N contents higher than 0.03mgL-1 and 65% of the samples collected from the agricultural fields contained NO3- N higher than 0.03mgL-1 in contrast to 15% of samples from residential areas. Results also revealed an inverse relationship between the NO3-N concentrations and the depth of the sampling aquifers (SHW>MHP>DMBH). Most of the analysed samples contained NO3-N load less than the fixed threshold limit by WHO (2006) for drinking purposes of below 10mgL-1, thus, rendering the waters safe for drinking purposes.
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    PRELIMINARY APPRAISAL OF CHEMICAL AND GEOTECHNICAL PROPERTIES OF CLAY DEPOSITS IN DOMA AREA, MIDDLE BENUE TROUGH, NIGERIA
    (Department of Geology and Minning, Nasarawa State University Keffi, 2011-06-06) Essien, B.I.; Obrike, Stephen E.; Anuda, G.K.; Iyakwari, Shekwoyandu
    A appraisal of the chemical and geotechnical properties o f the Dorna sedimentarp claps was conducted and consequently assessed for their possible industrial potential.The chemical analpsis o f samples repealed the predominance of ) 2.04-9.01%(,1:0٤)0,94- 3.94%/,7٧40000.83-1.10%/,04000.05-0,91%( ,* 2 0 )0.21-1.82%( 4/147420) 0.08-0.18%(. The characteristic physicalparameters o f the clap specimens included linear shrinkage (3.6-15.6%), plastic limit (15 20%), liquid limit (25 41%) andplasticitp index (5 20% ). 1716 chemical and geotechnical properties o f the Dorna claps indicated that they are potentially suitable for the production o f ceramics, pottery and refractorp bricks
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    Preliminary structural study of Landsat Imagery overWamba and Environs, Nasarawa state, Northcentral Nigeria
    (Department of Geology and Minning, Nasarawa State University Keffi, 2012-01-03) Anuda, G.K.; Obrike, Stephen E.; Iyakwari, Shekwoyandu; Ikpokonte, A.E.
    Wamba and environs is underlain by the migmatities, gneisses. Older Granites, Younger Granites, Awgu Shale and Lafia Formation. LANDSAT 5-TM imagery over the area has been analysed and interpreted in order to determine the lineament trends, drainage network and lineament density across the area. Rose (azimuth-frequency) diagram plots of the structures (lineaments) from both the imagery and field measurements show NE-SW, NNE-SSW, E-W, NNW-SSE andN-S directions with the dominant trends intheNE-SW andNNE- ssw directions. Two prominent faults (Fl, F2) were identified on the imagery. The superposition of the lineament map and drainage map depicts that the dendritic drainage pattern of the area is lithologically and structurally controlled. The lineament map, lineament density contour map, lineament density image map and lineament density surface map show that the lineament density is high around Monkwar, Zamatak, Ninkade, Mugu, Gwanzu and Garko underlain by migmatites, gneisses and Older Granites.
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    The risk o f groundw ater contam ination from land-use activities in shallow basem ent terrains, a case o f K effi and environs, N orth Central Nigeria.
    (Department of Geology and Minning, Nasarawa State University Keffi, 2017-03-13) Obrike, Stephen E.; Anuda, G.K.; Iyakwari, Shekwoyandu; Abubakar, Aisha Kana; Umbugadu, A.
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    Safety Practices in Surface Mining in North Central Nigeria
    (Department of Geology and Minning, Nasarawa State University Keffi, 2010-03-04) Baba, Adama Oleka; Iyakwari, Shekwoyandu; Obrike, Stephen E.; Anuda, G.K.
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    Upper Lithospheric Structure of the Middle Benue Trough, Nigeria, Derived from Analysis of Satellite Gravity Data
    (Department of Geology and Minning, Nasarawa State University Keffi, 2021-03-04) Anuda, G.K.; Obrike, Stephen E.
    The middle Benue Trough is the central segment of the Benue Trough, an elongate northeast orientated intracratonic rift basin in Nigeria. This study provides new information on the morphology/geometry of the upper lithospheric structures (Moho, crystalline crust thickness and crustal stretching factor) and tectonics in the middle Benue Trough and adjacent basement complex regions by analysis and three-dimensional (3D) inverse modelling of satellite Bouguer gravity anomaly data. Results from 3D inverse modelling reveal Moho depths varying from c. 24 ± 2 to 32 ± 3 km and crystalline crustal thickness values ranging between c. 20 ± 2 and 32 ± 3 km. Shallow Moho and thin crust occur beneath the Trough axial region, whereas deep Moho and thick crust underlay the basement complex regions and the Trough northwestern region. It also shows the presence of a prominent northeast-southwest (NE-SW) orientated, shallow Moho structures (c. 24 ± 2 to 27 ± 3 km deep) and thin crust (c. 20 ± 2 to 26 ± 3 km thick) within the Trough axial region. Comparisons of Moho depths with topography and Bouguer gravity anomaly values using profiles highlight that the observed broad, longer-wavelength near-positive Bouguer gravity anomalies over the Trough axial region are strongly associated with elevated (shallow) Moho and isostatic effect of lower topography. Crustal stretching factor (â) values obtained across the area range between c. 1.03 and 1.59 with moderately high values (c. 1.25 – 1.59) occurring in the Trough axial region. The tectonic implication of the results is that the crust/lithosphere beneath middle Benue Trough has been strongly affected/modified by intense regional, extensional and/or wrench (strike-slip) tectonics associated with past rifting events