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This research utilized various data types, including remote sensing (RS), aeromagnetic (AM), vertical electrical sounding (VES), and hydrogeological (HG) information, to create a groundwater potential map (GPM) of the Ogbomoso region in southwestern Nigeria. The lineaments obtained from the RS and AM results were merged to produce the lineament density (LD) map of the Ogbomoso area. One hundred and sixty-five VES data were collected for this study. The Ogbomoso area has a distinct geoelectric sequence that consists of various layers. These include the topsoil, weathered/saprolite, saprock, fractured basement, and fresh basement rock. Eight groundwater conditioning factors (GwCFs) were considered to ensure an accurate assessment of the groundwater potential (GP) in the Ogbomoso area. Stepwise weight assessment ratio analysis (SWARA), a multicriteria decision analysis (MCDA) technique, was used to assign weights to each GwCFs. The given weight was normalized, and a coefficient of coherence was established. SWARA helped characterize GP in the Ogbomoso area into different categories. It was discovered that there is a 0.63-degree correlation between well locations and GPM produced for the Ogbomoso area. This confirms that the SWARA modeling technique is reliable for predicting groundwater potential in any typical basement complex terrain worldwide. [ABSTRACT FROM AUTHOR]

The basin environment is a widely studied subject in both geology and geophysics for its economic significance in energy and mineral explorations. However, the estimation of the basement depth is often a challenging task given the complexity of the basement relief and lateral physical property change. Previous works simplify the problem by only inverting for the depth to the basement, and more recent studies have suggested the need to incorporate the variation of physical properties to improve basement structure imaging. In this study, we develop an inversion method with the associated workflow to simultaneously recover both the depth to a magnetic basement and a laterally varying magnetic susceptibility in the basement rock. To achieve this, we employ a set of constraints on the inverse problem. Particularly, both the recovered susceptibility and basement depth models are bounded below a possible maximum value, and the depth model is guided by a few depth points obtained from the resistivity models that are obtained from the one‐dimensional blocky inversions of magnetotelluric (MT) data. In addition, we apply the fuzzy C‐means (FCM) clustering to the susceptibility model during the inversion and use the inverted cluster centers to differentiate for different geological units in the basement. To show the effectiveness of our work, we compare the existing approaches and our method using two test inversions on one synthetic model resembling the basin–basement environment before demonstrating our method on a field data example with magnetic data collected by the U.S. Geological Survey (USGS) over the Illinois Basin. Our results show improved recovery in both basement relief and susceptibility in the basement rock, and inversion with field data is able to identify three different susceptibility zones in basement rock below the Illinois Basin. [ABSTRACT FROM AUTHOR]

This study assessed and compared selected soil properties, oil and grease content, and thermophysical parameters of sandy loam soils from two representative automobile mechanic village (MV) on two different geological formations in Ogun State, Nigeria. The two locations: Abeokuta and Sagamu are situated on a basement complex and Cretaceous-sedimentary formations, respectively. Ten sample points were established on each MV. Physico-chemical and in-situ thermal properties were measured using standard methods and KD2 Pro thermal analyzer, respectively. Three different regression models (linear, semi-log and double-log) were generated for the prediction of thermal conductivity ([Formula: see text]) and specific heat capacity ([Formula: see text]). Topsoils in both MVs are slightly acidic to neutral, with an average oil and grease content > 100 mg/kg. Results of thermophysical parameters revealed that the average [Formula: see text] values in MV soils of basement complex and sedimentary backgrounds were 1.656 and 1.988 W/mK, respectively. The average [Formula: see text] values in Abeokuta and Sagamu MV soils are 2.295 and 3.043 MJ/m3K, respectively. The regression analysis showed that the double log model performed better than both linear and semi log models for predicting [Formula: see text] at both locations. All the tested regression models have good prediction effects on [Formula: see text] at location within cretaceous sedimentary, whereas linear and double-log models proved feasible for predicting [Formula: see text] at location underlain by basement complex.

Water borehole failures in Nigeria's middle Benue Trough are caused by imprecise aquifer features. This study employed empirical data to understand hydraulic parameters, anticipate regional groundwater potential, and explain borehole failures in difficult geological locations. 89 VES stations and quantitative data interpretation were required to determine the geoelectric properties beneath each station. Aquifer layers were delineated and their resistivity and thickness combined using geo-environment specific relations to yield transmissivity, hydraulic conductivity for both basement complex and sedimentary environments variously. Results show that aquifer resistivity ranges from 4.5 – 984.4 ohm-m; aquifer layer thickness varies from 4.4 m – 96.7 m with average thicknesses in sedimentary environment considerably greater; hydraulic conductivities range from 0.056 – 30.15 m/day, Transmissivity values range from 0.31 – 1281.36 m2/day. Log transformed transmissivity values range from 3.51 – 7.1 m2/day. Approximately 60.34% of the entire study area falls within transmissivity magnitude III and IV and can only support withdrawals for local water supply adequate for small communities and private consumption only and this may be the inferred cause for the low yield and high borehole failure rates. Understanding hydraulic characteristics is critical for 6controlling groundwater; research advances knowledge of transmissivity and conductivity in complex terrain. HIGHLIGHTS The Benue Trough in Nigeria is experiencing a concerning trend of water borehole failures.; The researchers collected data from 89 VES stations.; 60.34% of the study area falls within the limits of limited groundwater availability.; Aquifers in the study area can only support water withdrawals for local water supplies in small communities.;

The pegmatites of Ogodo-Odobola area around Ajaokuta, Central Nigeria belong to the pegmatite belt of Central Nigeria. A detailed geological mapping of the pegmatites and host rocks was conducted with the aim of understanding their mode of occurrence and field relationship and to assess their mineralization potentials. Twelve (12) representative samples of rocks were selected for petrographic analysis. The results show that the area is underlain by migmatite-gneiss, schist, with intrusions of granite and pegmatite. The pegmatites occur in tabular form with varying widths (2 centimetres - 6 metres) and lengths (12 - 200 metres). Principal joint direction is NNE-SSW which is believed to have influenced the pegmatite emplacement. Petrography of the representative rock samples revealed an average mineralogical composition of biotite (23.90%), microcline (22.15%), hornblende (15.05%), quartz (10.65%), plagioclase (10.35%), muscovite (8.00%), myrmekite (0.20%), and opaque and accessory minerals (9.70%). The pegmatites were found to be dominated by microcline and plagioclase feldspars, and then muscovite, biotite, and accessory and opaque minerals. The pegmatite of the Ogodo-Odobola area is worth probing as the results have shown prospect for possible economic minerals. [ABSTRACT FROM AUTHOR]

Geological mapping and petrographic studies of rocks provide useful information on texture and mineralogical composition of rocks which can be used in the exploration and exploitation of any associated mineralization. However, few regional studies have been conducted in Minna and environs. Here, preliminary field mapping and petrography of out crops in Saigbe environ were conducted to determine their identification, structural and mineralogical composition. Twenty-one rock samples were collected, eight of which were used for thin section analysis. Joint directions were measured and plotted on rose diagram. Results show that Saigbe is underlain by schist, amphibolite and granite with minor pegmatite intrusions. Joints, faults, fold and foliations constitute main structures. Joints in the schists trend NE-SW, while those in the granites trend NW-SE, suggesting different episodes of emplacement for both rocks. Petrography revealed that the schists comprised quartz, biotite, muscovite, plagioclase and opaque mineral, while the amphibolites are composed largely of quartz, hornblende, plagioclase feldspar and opaque minerals. The granites are composed of quartz, microcline, plagioclase feldspar, muscovite and opaque minerals. The pegmatite dykes in the granites comprised quartz, plagioclase feldspar, orthoclase feldspar, muscovite and gemstones, hence interpreted as product of residual melt. The pegmatites make interesting target for mineral exploration. [ABSTRACT FROM AUTHOR]

The use of landfills has been applauded in municipal solid waste management as a critical solution to open dumping and burning. Selection of suitable landfill sites presents a challenge as it involves integration of numerous criteria in waste management and sustainability template without prejudice to the environment. The aim of this paper is to delineate appropriate sites for landfills in the basement complex of Ado-Ekiti, South-western Nigeria. The need for landfill sites that meet scientific and environmental requirements is compelling. Landsat-8 OLI & TIRS images of 2016 and ASTER imagery (30m resolution) were acquired to generate land use/land cover maps and site selection criteria. The composite image was subjected to supervised classification using the maximum likelihood algorithm in ArcGIS 10.2.2. The classification permitted the extraction of the land use of urban areas (settlements), agricultural areas, and bare land. Geoelectrical characterization was deployed to produce in situdata. Integration of data using a weighted overlay yielded a landfill suitability index map that classified the area into four categories of unsuitable, partly suitable, moderately suitable, and very suitable locations of landfill sites. Sanitary landfills are desirable to mitigate the adverse effects of widespread open dumping. Doi: 10.28991/HEF-2022-03-03-05 Full Text: PDF

To fully harness the increasing number of observations and variant data sets available and put them to efficient use in geological studies aimed at solving earth science-related problems, GIS technique is a veritable tool. The dynamic techniques and the complex nature of earth sciences is a serious cause for worry for geologists. In this work vertical electrical sounding (VES) was integrated with geographic information system (GIS) to delineate subsurface characteristics and evaluate groundwater potential zones in Idi Ayunre, Oluyole Local Government Area, Oyo State. The results of the VES curves obtained from the partial curve matching were used to constrain the interpretation by the computer using iteration software known as WINRESIST® and extended analysis on the data set was done using geostatistical analysis tool on archGIS 10.0®. The Root Mean Square (RMS) errors for the analysis were found to be very low with an average of 2.96% . This underscores the reliability of the analysis tool for this type of work. The area is dominated predominantly by Type-H curves which amassed twenty (20) out of the twenty-one (21) VES and one (1) VES producing a type-K curve. The VES results revealed a maximum of three geo-electric layers, viz: topsoil, weathered layer, bedrock respectively. The yields of wells dug in most of these locations may be insufficient, even for domestic use because of its relatively small thicknesses. However, at a depth of 7.8 m, a fractured zone occurs in VES 10 with resistivity value of 21.2 Ωm suggesting the presence of groundwater, which may be considered the main aquifer units suitable for groundwater exploration.

The study was inspired by the need to diversify the country's economy from oil-based to non-oil-based, of which solid mineral resources are prominent, in addition to some scientific research interests derivable from the clear understanding of the petrological settings in the area. The Nigeria geological setting comprises basically of basement complex, which hosts most of the mineral resources in the country, and a sedimentary basin. Over 95% is the basement complex in the study area. The aim was to infer 2D models for characterizing the lithological series of rock intrusions within the host rocks. Gravity data were collected over 4 months using LaCoste-Romberg Gravimeter G446 from 1579 stations over 23,235.3525 km2. The stations were tied to the International Gravity Standardization Net (IGSN). Mean density values from 142 samples of rocks are as follows: granite 2.61 ± 0.07 g cm−3, pegmatite 2.63 ± 0.06 g cm−3, granodiorite 2.67 ± 0.05 g cm−3, dolerite 2.65 ± 0.07 g cm−3, and gabbro 2.68 ± 0.06 g cm−3. The Bouguer anomaly field ranges from − 300 to − 20 mGal, while the residual anomaly varies between − 200 mGal and 120 mGal. The general NE–SW trend obtained in all the anomaly fields agrees with the regional trend in the Nigeria Basement Complex. High gravity gradients (maximum 5 mGal/km) from most intrusions in the area confirmed sharp vertical contacts. The largest depth and thickness of the low-density intruding granites are 27 and 44 km; the high deep root here suggests a magmatic mode of emplacement. Their density contrast ranges from − 0.57 to − 0.3 g cm−3. Isolated denser ultra-basic intrusions, whose density range is 0.2–0.4 g cm−3, occurred with depth and thickness of 14 and 44 km in the area. These intrusions were suspected to be of metasomatic origin. Furthermore, a low-density sill-shaped structure, 18-km deep and 2.5-km thick, was mapped in the southern part of the study area. In conclusion, the occurrence of deep-rooted gravity-low causative bodies confirmed low-density mineralogical presence in some parts of the area. Also, metasomatic intrusions confirmed the occurrence of chemical alterations whereby the host rocks were replaced by denser/mafic rocks of high-gravity field mineralogical compositions. [ABSTRACT FROM AUTHOR]

The maximum yield of 90,000 m3/day from the existing Gubi dam in Bauchi will barely meet the water demand beyond 2030 at an average water use of 100 litres per capita/day. For higher water demand of up to 250 litres per capita/day expected in an urban centre, the existing dam capacity is inadequate, and the demand should grow to 253,102 m3/day by 2037. This is the rationale for this study, which showed the feasibility of a new dam through technical reviews and analysis of topography, hydrology of the site, field and laboratory investigations, computer analyses and designs. Hydrologic simulation of rainfall-runoff processes for 57 years of rainfall data using the Soil Conservation Service (SCS) method gave an annual runoff volume of 59 Mm3 on a stream in Miri, which can be harnessed to assure adequate water supply in the metropolis. This will require the construction of a 25 m high embankment dam. Topographic survey and analysis indicated that the proposed site has good water retention capability. Although net flow adjustment analysis showed a high evaporation loss of up to 13.5 Mm3 annually, seepage loss is expected to be small in view of the underlying basement complex rock formation.

A geophysical method of investigation has been deployed in order to give a quick overview of the nature and the rapidly changing subsurface lithologies that characterized Yikpata, Share, Kwara State, Nigeria. A total of nine (9) vertical electrical soundings (VES), using Schlumberger Array uniformly divided into three groups: basement, basement/sedimentary boundary and sedimentary terrain, and horizontal profiling (HP) using Wenner Array were deployed for this study. The study revealed variation in the subsurface resistivity, thus depicting changes in lithology/rock types along this basement-sedimentary contact zone. The interpretation revealed that the Basement Complex terrain consists of 3-4 geoelectric layers: the topsoil, the weathered, weathered/fractured basement and the fractured basement. Depths beyond ≥ 12 m where the fractured basement occurs can be target for groundwater exploration and structurally controlled mineralization. The resistivity values around the Basement/Sedimentary unconformity zone shows about 3 – 4 geoelectric layers. The resistivity values show remarkable characteristics of the basement and the sedimentary terrains and also reflect the rapidly changing subsurface geology in the area. In the sedimentary terrain, 4 geoelectric layers were delineated: Top soil, clayey sand, sandy clay and clay. Geoelectric sections reveal the variation in the subsurface lithology laterally and vertically. The study has shown that the resistivity method can be an aid to understand complex geologic environments with rapidly changing subsurface geology. Also, the knowledge of the geology of an area is very important in order to make sensible geophysical interpretation.

Expansive soils are one of those kinds of soils whose volume change takes place while it comes in contact with water.It expands during the rainy season due to intake of water and shrinks during dry season. The wetting and drying process of a sub)grade layer composed of black cotton soil result into failure of pavements in form of settlement and cracking. Therefore, prior to construction of a road on such sub-grade, it is important either to remove the existing soil and replace it with a non-expansive soil or to improve the engineering properties of the existing soil by stabilization using additives such as egg shell powder and palm kernel shell which is source locally The black cotton (expansive) soil was obtained from a borrow pit on the basement complex at Igbo-Ora in Oyo State, South-Western Nigeria. The borrow site lies within the coordinates Longitude 7⁰24'45" and latitude 3⁰18'34". Another black cotton (expansive) soil was obtained from a borrow pit on the sedimentary formation at Idogo in Ogun State, South-Western Nigeria. The borrow site lies within the coordinates 6⁰ 50' 6" N and 2⁰ 58' 42" E. The black cotton soils used in the study were collected from depths between 0.3-1.0m below ground level. In line with BS 1377 (1990) and other relevant codes, compaction tests were conducted on the black cotton soils on basement complex and sedimentary formation for the determination of maximum dry density, bulk density and optimum moisture content of the natural soils. From the results, the bulk and dry densities of black cotton soil on the sedimentary formation are higher than that of basement complex while the later required more test water content to achieve the maximum bulk and dry densities. The optimum moisture content of basement complex is higher than that of sedimentary formation. It could be seen from the results that the type of formation played a prominent role in their behaviors to the compactive efforts. [ABSTRACT FROM AUTHOR]

Expansive soils tend to be strong in its dry state but when in a wet condition, it tends to lose its strength. The low strength and excessive volume changes of black cotton soil make their use in constructions very difficult. The properties of the black cotton soil may be altered in many ways through mechanical, chemical and other means. Therefore, it becomes very important to investigate the physical and engineering properties associated with the black cotton soil especially as a construction material. The black cotton (expansive) soil was obtained from a borrow pit on the basement complex at Igbo-Ora in Oyo State, South-Western Nigeria. The borrow site lies within the coordinates Longitude 7⁰24'45" and latitude 3⁰18'34". The black cotton soils used in the study were collected from depths between 0.3-1.0m below ground level. The palm kernel shell wastes were taken from palm oil producing plant along Ilaro-Owode Road, Ilaro, Ogun State, Nigeria. The palm kernel shells were broken into pieces passing through 5mm sieve and then substituted for black cotton soil from 0% to 30% at 10% intervals while 0% palm kernel shell substitution served as control experiment. In line with BS 1377 (1990) and other relevant codes, consistency tests were conducted on the composite materials of black cotton on basement complex mixed varying degrees of palm kernel shells, for the determination of liquid limit, plastic limit, etc. From the results, shrinkage limit reduced from 2.0cm for 0% substitution to 1.5cm for 30% substitution of palm kernel shell substitution in black cotton soil on basement complex. The percentage shrinkage limit became constant at 30% palm kernel shell substitution which is an indication that the optimum percentage substitution of palm kernel shell in black cotton soil on basement complex is 30%. [ABSTRACT FROM AUTHOR]

Expansive soils are one of those kinds of soils whose volume change takes place while it comes in contact with water. Therefore, prior to construction of a road on such sub-grade, it is important either to remove the existing soil and replace it with a non-expansive soil or to improve the engineering properties of the existing soil by stabilization using additives which are sourced locally. The black cotton (expansive) soil was obtained from a borrow pit on the basement complex at Igbo-Ora in Oyo State, South-Western Nigeria. The borrow site lies within the coordinates Longitude 7⁰24'45" and latitude 3⁰18'34". The black cotton soils used in the study were collected from depths between 0.3-1.0m below ground level. The eggshell wastes were taken from Obasanjo Farms, Ota, Ogun State, Nigeria. The eggshells were milled into powder and then substituted for black cotton soil from 0% to 30% at 10% intervals while 0% eggshell powder substitution served as control experiment. In line with BS 1377 (1990) and other relevant codes, consistency tests were conducted on the composite materials of black cotton (on basement complex) mixed with varying degrees of eggshell powder for the determination of liquid limit, plastic limit, shrinkage limit, etc. It is evidently clear from the results that the percentage shrinkage limit became constant at 30% eggshell powder substitution in black cotton soil on basement complex which is an indication of constancy of volume. [ABSTRACT FROM AUTHOR]

Groundwater exploration in Basement Complex zones is somewhat difficult due to the erratic nature of groundwater occurrence in these zones. This has led to high failure rates in wells constructed in these settings. This problem has, however, been further complicated by the high cost of geophysical surveys to locate suitable drilling points. Therefore, there is the need to explore cheaper and more systematic techniques for optimal results. This study focused on the delineation of groundwater potential zones (GPZs) in Miri and environs, northeastern Nigeria. Remote sensing and geographic information system (GIS) methods were employed for the identification of structural and geomorphological controls of groundwater. Five thematic maps comprising lithology, lineament density, drainage density, slope, and elevation were generated while thirty-three vertical electric soundings (VESs) were employed for characterization of the saprolitic units in the study area. Data evaluation entailed integration of thematic maps using overlay analysis to generate a groundwater potential map of the study area and estimation of geoelectric parameters to verify the resulting GIS-based map. The geospatial studies revealed three GPZ which include good zones (3%), moderate zones (65%), and poor zones (32%). The VES revealed 3–4 geoelectric layers, with dominantly clayey sand (thickness of 1–65 m and resistivity of 5.4–396 ohm- m) aquifer units of moderate potential. The validation of GPZ map with the VES data showed that the low potential zones are attributable to poorly developed regoliths in the northern parts of the study area. The study showed that groundwater potential in the Miri area is medium to low and the clayey sand saprolitic units and saprocks constitute the aquifer units. Groundwater recharge in the area is influenced by geomorphological features. [ABSTRACT FROM AUTHOR]

The unavailability of water has been a major threat to agricultural and commercial activities in Ilora, Oyo central, Nigeria. This study combined GIS, remote sensing, and geophysical methods for groundwater potential zone mapping within the area in an attempt to identify prospective zones for borehole drilling activities. Landsat 8 OLI, ASTER DEM, geological, geophysical, and soil data of the research area were acquired for this study. To map the groundwater potential of the area, eight thematic layers that influence groundwater occurrences and movement controlling factors such as, geology, elevation, slope, land use land cover (LULC), fault proximity, soil, lineament density, and drainage density were mapped out from the acquired data of the area. The influence of each theme and subunit/class on groundwater recharge based on previous studies were evaluated using Analytical Hierarchical Process (AHP). The groundwater potential of the area of study was qualitatively classified into five classes, namely: very high, high, moderate, low, and very low which account for 0.3%, 7.8%, 54.8%, 35.6%, and 1.5% of the total area, respectively. The results were cross validated using well data from the area and 88.9% correlation and 0.74 kappa coefficient were achieved. The groundwater potential map generated in this research could be used as a preliminary reference in selecting suitable sites for groundwater resource exploitation in the area to ameliorate the current scarcity of water in this region. [ABSTRACT FROM AUTHOR]

The study aims at differentiating lithologic units, general structural trends and orogenic implications of crystalline rocks within part of Oban Massif, Southeastern Nigeria. Field study involve geological mapping, rock description and structural measurement, while laboratory analysis covered photomicrograph. Field observation and microscopic analysis reveal five petrological units; gneisses, schists, granodiorite, pegmatite and quartz veins. The rocks are generally siliceous and quartzo-feldspathic. The schist show foliation planes trending majorly in the NE-SW direction. The gneisses were highly fractured, indicative of a polyphase deformation. Structural elements such as joints, fractures, foliations and veins show series of deformational episodes that affected the area. Rose diagram plot for these structures show the NE-SW direction indicative of the Pan-African orogeny (600±150 Ma) and interpreted as the most recent event affecting the area. NW and NE trending joints are considered to be tectonic in origin based on their alignments with major structures of the area. Furthermore, the structures also showed weak NW-SE and E-W trends, an imprint of older (Kibaran orogeny) deformational episodes. [ABSTRACT FROM AUTHOR]

Two geophysical tools were used to delineate the configuration of the Nubian sandstone aquifer in the study area. Three hundred magnetic points were measured and analyzed to evaluate the subsurface structural setting and to trace the basement relief, which control the aquifer's geometry. The magnetic interpretations refer to dominant faults that strike in various directions, namely N–S, NE–SW, and NW–SE. The top of the basement complex was recorded at depths of 384–1286 m, and the aquifer thickness ranged from 299 to 1169 m. Thirty vertical electrical sounding points of AB/2 with depths ranging from 1.5 to 700 m were used to estimate the parameters of the Nubian sandstone aquifer. The geoelectrical data indicate that the area consists of 5 units; the first unit is composed of sand and gravel, the second unit of ferruginous sandstone, the third unit of clay, the fourth unit of dry sandstone, and the last unit of sandstone saturated with groundwater. The groundwater in the study area is freshwater of high quality usable for all purposes. [ABSTRACT FROM AUTHOR]

Information on the distribution of various forms of iron in soils are valuable in the study of soil genesis. The objective of this study was to to evaluate the pedogenic forms of iron in soils developed over basement complex and basaltic parent materials of the study area. Geologic units considered in the basement complex area were granite gneiss, biotite granite and migmatite. Stratified random sampling formed the basis for field work. Soil sampling was carried out by digging at least two soil profile pits in each geologic unit. Organically bound, amourphous and total iron oxides were estimated using 0.1 M sodium pyrophosphate, acidified (pH 3) ammonium oxalate, and dithionite-citrate-bicarbonate method, respectively. The total Fe in the soil samples were determined after a mixed acid digestion. In general, total iron fractions were statistically similar among the soils of basement complex geologic units but significantly lower than those of soils derived from basaltic rocks. However, the distribution of iron oxide fractions was similar among the basement and basaltic geologic units. Furthermore, there were significant differences in the distribution of iron oxides in the B horizons of basement complex derived soils. Consequently, the quantity of iron oxides in the B horizon was in the order migmatite > biotite granite > granite gneiss. About 70% of total iron oxides in the soils over granite gneiss, biotite granite and basaltic rocks was amorphous in nature. Furthermore, total iron oxides constitute less than 20% of total clay both in the basement complex and basaltic soils.

Investigation of groundwater contamination from an active landfill was carried out in Saje, Abeokuta Ogun state, Nigeria using geophysical and geochemical methods. Four resistivity traverses picked up within the landfill. Wenner array electrode configuration was adopted and the data were interpreted using RES2DINV program. Quantitative valuations were accomplished by geochemical and hydrogeochemical facies of groundwater samples collected from ten dug wells in the arcade of Saje landfill. Fifteen parameters were analysed in the groundwater samples. The results of the 2D resistivity analysis showed that there is a constant and progressive increase in the depth of migration of the contaminants generated from this landfill site into the subsurface environment as its ages. The results of both physical and chemical parameters of the water analysis revealed that all the parameters were 100% in compliance with the World Health Organization (WHO) and Nigerian Standard of Drinking Water Quality (NSDWQ) standard permissible limits for drinking, water except for pH (90%), Calcium (80%) and Lead (80%). The classification of water samples of the study area using Piper Trilinear diagram revealed that 70% of the analysed water samples are of CaHCO3 (fresh water) type, 20% are of CaCl2 type and 10% are CaMgCl type. The calculated values of irrigation parameters such as; Magnesium Absorption Ratio, Sodium Absorption Ratio, Total dissolve solid, Soluble Sodium Percentage, Kelly‘s Ratio and Permeability Index for most of the groundwater samples were found to be suitable for irrigation. The groundwater quality index evaluation acquired for the study area ranges from 3.8 – 18.1. This study established that the groundwater around this region is 100% suitable for drinking purposes. [ABSTRACT FROM AUTHOR]

A few investigations have been done regarding the soil quality index (SQI) for various locations, soil types, and states. Still, little has been reported regarding SQI for both surface and control sections, especially for the Northern Guinea Savanna of Nigeria. Due to the subsurface property pedogenic influence on soil function, it is crucial to assess SQI using surface and subsurface properties as both properties influence soil productivity. We investigated the potentials of choosing a minimum data set for soil quality indicators and assess soil quality (SQ), using both surface and entire soil pedon data for the soils on the basement complexes. Both additive and weighted soil quality indices and different scoring methods (linear and non-linear) were used in evaluating SQ. Out of the twenty-three soil properties subjected to PCA, eight indicators (TEB, clay, silt, K, EA, EC, BD, and Fe) were selected as the minimum data set (MDS). There was not much difference in the calculated soil quality using the non-linear additive (SQI-NLA), linear additive (SQI-LA), linear weighted (SQI-LW), and non-linear weighted (SQI-NLW) for the soils as they were all rated low (SQI < 0.55). The estimated SQI for the control section had relatively higher values than the surface soil, thus suggesting the need to incorporate both surface and entire soil profile properties in assessing SQ as both are important in integrating the relationship between soil properties and management goals which eventually provides complete information that affects the production of crops. [ABSTRACT FROM AUTHOR]

A geophysical method of investigation has been deployed in order to give a quick overview of the nature and the rapidly changing subsurface lithologies that characterized Yikpata, Share, Kwara State, Nigeria. A total of nine (9) vertical electrical soundings (VES), using Schlumberger Array uniformly divided into three groups: basement, basement/sedimentary boundary and sedimentary terrain, and horizontal profiling (HP) using Wenner Array were deployed for this study. The study revealed variation in the subsurface resistivity, thus depicting changes in lithology/rock types along this basement-sedimentary contact zone. The interpretation revealed that the Basement Complex terrain consists of 3-4 geoelectric layers: the topsoil, the weathered, weathered/fractured basement and the fractured basement. Depths beyond = 12 m where the fractured basement occurs can be target for groundwater exploration and structurally controlled mineralization. The resistivity values around the Basement/Sedimentary unconformity zone shows about 3 - 4 geoelectric layers. The resistivity values show remarkable characteristics of the basement and the sedimentary terrains and also reflect the rapidly changing subsurface geology in the area. In the sedimentary terrain, 4 geoelectric layers were delineated: Topsoil, clayey sand, sandy clay and clay. Geoelectric sections reveal the variation in the subsurface lithology laterally and vertically. The study has shown that the resistivity method can be an aid to understand complex geologic environments with rapidly changing subsurface geology. Also, the knowledge of the geology of an area is very important in order to make sensible geophysical interpretation. [ABSTRACT FROM AUTHOR]

Abstract Integrated investigations involving remote sensing and GIS have been conducted with the objective of achieving optimal results in sustainable groundwater development in Ado-Ekiti, south-western Nigeria. The hard rock terrain in the region presents challenges in groundwater exploration. Landsat imageries were used for landuse/landcover mapping and lineament analysis for groundwater prospecting. Shuttle Radar Topographic Mission Digital Elevation Model was used for drainage network extraction, slope and geomorphological analysis. Thematic maps were generated, analysed in terms of hydrogeological importance and reclassified for integration using appropriate software. The groundwater potential maps generated were validated against the existing groundwater yield data. The light vegetation and bare soil area cover was 110.9 km2, with the rock outcrops covering a total area of 14.9 km2. Hydrogeomorphic units delineated included hills, pediments, pediplains, alluvium and valley fills. The lineaments showed predominantly NNW–SSE, ENE–WSW and NNE–SSW orientations and subsidiary NW–SE and W–E trends. Application of geospatial techniques has been recognized. The methodology provides improvements in the understanding of the hydrogeological characteristics of the basement terrain. These will aid planning and management of groundwater resources in the crystalline basement terrain.

The gneissic rocks of Oka-Akoko area forms part of the Migmatite-Gneiss-Quartzite Complex of the Southwestern Nigerian Basement Complex. The petrologic units in the study area include grey gneiss, granite gneiss, Older granite, charnockite and minor felsic and basic rocks. Twelve gneissic rock samples comprising six granite gneiss and six grey gneiss from the area were collected for petrographic and geochemical analyses. Petrographic analysis revealed that the granite gneiss is more enriched in quartz and alkali feldspar than the grey gneiss. The grey gneiss is richer in plagioclase, hornblende and opaques compared to the granite gneiss. Interpretation of petrographic and geochemical analyses results revealed that Oka-Akoko granite gneiss and grey gneiss were derived from igneous protoliths of granitic and granodioritic compositions respectively. The grey gneiss is ferroan, alkalic to alkali-calc and metaluminous suggesting that its igneous protolith(s) is a M-type granitoid derived from melting of rocks from upper mantle or lower crustal region under conditions of limited availability of H2O and low oxygen fugacity while the granite gneiss is magnesian, alkali-calc and slightly peraluminous suggesting that its igneous protolith(s) is an I-type granitoid derived from the partial melting of crustal igneous rocks.

Plinthite occurs in most parts of savannah soil at varying depths, thus limiting the productivity of the soil for crop production. However, plinthic soils are not well defined in the USDA classification. Therefore, we surveyed nine plinthites bearing pedons, to characterize their suitability, quality and sustainability over the basement complex formation in southwestern Nigeria; and to suggest new classification based on USDA and FAO classification systems. In the entire land area, two types of hardened plinthites were identified: 41% with petroferric contact and 59% with petroplinthite. The percentage of aggregate soil quality indices of both petroferric contact and petroplinthite was low to moderate, ranging from 32% to 56%. Sustainability indices of the soils ranged from 20 to 37 with petroferric contact have the lowest index while soils with petroplinthite have the moderate index. Setting up an integrated conservation structure with soil amendments is essential for the sustainability of petroplinthite soils but petroferric contact, even with high inputs, cannot sustain intensive cropping, and therefore, recommended for pasture and forestry. The inclusion of hyperplinthic and orthoplinthic in USDA and FAO-WRSB classification systems as classes of petroplinthite is hereby suggested. [ABSTRACT FROM AUTHOR]

The area which transcends the Precambrian basement complex onto the Sokoto sector of the Iullemmeden basin in northwestern Nigeria presents a unique prospect for geothermal exploration research in the absence of regional heat production data, despite its tectonic history and depositional characteristics. In this study, geophysical exploration employing radiometric technique was adopted to classify the petrologic units within the fringes of the Iullemmeden basin and the adjoining crystalline basement complex so as to estimate the radiogenic heat potential within the terrain that may support geothermal considerations. Airborne radiometric measurements acquired over the area were digitized and processed to obtain radioelement concentration maps and the K/Th/U ternary map. Results show that the ranges of measured concentrations of 40K, 238U and 232Th are 4.6 to 18.9%, 0.7 to 4.9 ppm and 4.6 to 18.9 ppm respectively. Radiogenic heat estimation derived from radioelement data within eight petrologic units comprising quaternary sediments, schist, carbonates, shale/clay, younger granites, older granites, gneissic rock and migmatite showed that the lowest radiogenic heat production estimates ranging from 0.27-0.66 μW∙m-3 were recorded in the sedimentary terrain within the quaternary sediments while the highest radiogenic heat production values of between 2.04 to 2.34 μW∙m-3 were recorded in the basement complex within gneissic rocks. The spatial distribution of radiogenic heat in the area showed an increased heat gradient within the basement complex and a diminishing heat gradient over the Iullemmeded basin. [ABSTRACT FROM AUTHOR]

The Neoproterozoic basement complex of Egypt outcrops in the Eastern Desert (ED) and southern Sinai, and is regarded to represent the northwestern continuation of the Arabian–Nubian Shield (ANS). The area west of Berenice has been given little attention, although it represents the key to understanding the geologic history of the South Eastern Desert and the entire ED. The present work is an integrated study using remote sensing (Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data imagery) and field-structural data to assess their utility in lithologic mapping and in detecting alteration mineral zones with considerable accuracy. A false-color-composite image, color-ratio composite image, decorrelation stretch, mafic index (MI), and quartz index (QI) were used to discriminate and map the various rock units. Correlation of False-color images of the ASTER band combination (7, 3, 1) with previous lithological mapping studies of the study area allow preliminary discrimination of different lithologies and drawing a base map. Subsequently, ASTER band ratios tested (4/1, 3/1, 12/14) and (4/7, 4/6, 4/10) with the ground truth data were used to refine the base map and construct the digital detailed geologic map. Petrographically, the investigated rock samples show kaolinite, chlorite, and epidote in alteration zones. The spectral angle mapper (SAM)-supervised classification using reference spectra of the USGS spectral library was used for detecting alteration zones. For verification, total accuracy assessment was carried out to evaluate the band combination and band ratios used in the lithologic mapping. That reached to 85.01% for band ratio 4/1, 3/1, 12/14 in RGB. [ABSTRACT FROM AUTHOR]

Investigations were made to reflect the genesis and classification of soils along a toposequence in the Teaching and Research farm of Taraba State University. The topographic map of the farm was developed in the ArcGIS 10.8 environment and a profile graph plotted out. One profile pit was sunk in each elevation range to represent soils in the summit, shoulder, back slope, foot slope and toe slope positions using the free survey approach. The soils were deep, well drained and generally described as A, B, C soils with extensive B horizons that showed clear illuviation of clay and sesquioxides. The soils were brown (7.5YR 3/4), dark brown (10YR 3/3) and dark yellowish brown (10YR 4/6) in the surface and dominated by sand with bulk density values that exceeded 1.5 Mg/m3. Soil pH values were moderately acid to neutral while organic C and exchangeable bases were low in all but foot slope position where high values of organic carbon were obtained in the surface soils. The content of dithionite and oxalate Fe and Al, and their derivatives indicate intense weathering condition of the soils as well as their combined movement with clay to endopedons. However, moderately high CEC and the likely presence of montmorillonite (via CECE/clay) are indications that the soils had good potentials for agriculture. Among the soil forming processes in the area were mineralization, eluviation-illuviation as well as ferritization. The soils were classified as Typic Rhodustults (Pretic Acrisols), Arenic Haplustults (Chromic Acrisols) and Paleustults (Haplic Acrisols). [ABSTRACT FROM AUTHOR]

The success probability of water wells constructed in crystalline rock terrains is largely dependent on the size, location and interconnectivity of the fractures present in them as well as the amount and nature of the material that may clog the fractures. Geological and geoelectrical studies were proposed and conducted at Tatiko to determine the structures in the underlying basement rocks and evaluate their groundwater potential. Geological study was used to delineate the structural control on groundwater availability while the geoelectrical study (Vertical Electrical Sounding) was used to investigate the properties of the subsurface materials and determine their potential to host sufficient quantity of groundwater. Structural data were plotted on a rosset diagram and showed major structural control trending in the NW -- SE direction. Quantitative interpretation of the geoelectric data indicates that the major fractures are within the weathered to competent basement indicating good hydraulic connection between the weathered and fresh basement. The fractures are deepest within the region that showed thicker weathering and are as shallow as 7 meters in other regions. Apparent resistivity of the fractures ranges between 100Ωm and 1200Ωm in most parts of the area with the highest values in the west. An integration of the result clearly showed that the NW and SW parts of the study area are the most favourable for drilling and further groundwater studies and drilling is recommended to a depth of 40m to 50m. [ABSTRACT FROM AUTHOR]

In Basement Complex rocks where rainfall is seasonal, water provision in dry season depends on regolith aquifer. For effective exploitation of groundwater resources, it is reasonable that geophysical investigation be conducted before development of well. In many instances, geophysical surveys may be expensive or nonexistent. Hence, there is a need for spatial analysis which might advise water engineers within such environments. Vertical Electrical Soundings (VES) data of 53 locations conducted with ABEM SAS-1000 terrameter using Schlumberger electrode configuration were obtained from the hydrogeology Department of Kwara state Ministry of Water Resources and Lower Niger River Basin and Rural Development Authority, Ilorin. VES locational coordinates were recorded using handheld GPS device. Sound curves were evaluated by partial curve matching approach and computer iteration using WinResist. The results depict six geo-electric regional successions, namely: top soil, lateritic clay, weathered basement, fairly-hard basement, thin fractured and hard basement. The geo-electric succession identified was plotted in Surfer 12 environment, using kriging interpolation method to show spatial distribution pattern of this zone. The spatial pattern is expected to give an insight to the nature of spatial variability of geo-electric layers and assist drillers as well as water resources policy makers in their operations.

This paper reports the soil properties and agricultural potential of floodplain soil in Obufa Esuk Orok, Calabar and Awi, Akamkpa, Cross River State and characterized the soils to develop a baseline for soil improvement and increased agricultural productivity. Floodplain soil developed on coastal plain sand and basement complex soils were examined with regards to their physical and chemical properties. The results showed that both soils were coarse-textured with a high content of sand exceeding 70%, giving dominant textural classes of loamy sand and sandy loam. The soils were strongly to slightly acid in reaction with mean surface pH values of 5.54 and 5.43 for soil developed on coastal plain sand and basement complex. The surface soil developed in coastal plain sand within Obufa Esuk Orok, Calabar contains moderate amount of exchangeable Mg (0.8-2.2 cmol/kg), available P (10.0 -11.83 mg/kg), total N (0.20-0.25%) and organic carbon (2.51-3.05%) and was high in base saturation (93.11-95.50%) and low in exchangeable acidity. Conversely, the floodplain soil developed on basement complex in Awi, Akamkpa was rated low in key fertility indicators. Hence, floodplain soil under this study notably, those developed on coastal plain soil can be exploited for the cultivation of rice, oil palm, coconut, plantain, pineapple, pepper, fluted pumpkin and sugar cane with judicious application of lime, and N and K fertilizer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Vegetation pattern is influenced by bedrock geochemistry and soil thickness. • K enrichment is relatively high and less heterogeneous in the study area. • P enrichment is very low and highly heterogeneous in the study area. • the concentration of K is discriminately high in granitic rocks. • the highest concentration of P occurs in schist. The influence of lithospheric parameters on vegetation varies from one location to another, regardless of the prevailing climatic conditions. Reliable scientific information on the vegetation-environment relationship is crucial to sustainable agriculture and natural resource management. Poignantly, such information is not readily available, particularly in resource-poor countries. In this study, we assemble spatially referenced datasets on vegetation pattern, topography, soil thickness and bedrock geochemistry. We subject the datasets to global and local spatial regression analyses on GeoDa 1.18 and MGWR 2.2.1 platforms. Our intention is to examine the influence of lithospheric parameters on vegetation patterns over a climatically homogenous basin in the rainforest belt, southwestern Nigeria. The results of our study show that the variation in vegetation pattern can be explained by soil thickness, topographic curvature, and bedrock concentrations of major minerals. Bedrocks' KO 2 /Fe 2 O 3 enrichment and soil thickness are the main lithospheric parameters that influence vegetation pattern in the study area. Bedrocks' K enrichment is relatively high and less heterogeneous while P enrichment is very low and highly heterogeneous across the study area. Fe concentration is highly heterogeneous, with the highest enrichment recorded for schist and the lowest for gneiss. While the concentration of K is discriminately high in granitic rocks, the highest concentration of P is recorded for schist. Vegetation index is averagely higher on schist than on granitic rocks. Regression models show that bedrock geochemistry and soil thickness exert the greater influence on vegetation in the study area. Based on the available data, we observe that the study area's greenery can self-rejuvenate if left undisturbed. Our data show that the study area could support a large pool of forest carbon stocking. This potential makes the study area suitable for the UN REDD + program in Nigeria. [ABSTRACT FROM AUTHOR]

High resolution digital airborne data of sheet number 80, and the geology of the study area were acquired from the Nigerian Geological Survey Agency (NGSA). The data were analyzed using upward continuation, tilt derivative and first vertical filters. The residual field of interest was obtained using the polynomial fit ting technique and reduced to the magnetic equator to align the peaks of the anomalies with the centers of the source bodies. Application of the upward continuation filter to a vertical height of 2 km removed most of the very short wavelength anomalies emanating from very near-surface magnetized bodies and geologic noise, thereby enhancing the deeper bodies. The application of the tilt derivative highlighted areas of possible mineralization while the first vertical derivative filter shows lineaments along NE- SW, NW - SE and E - W major trends and NNE - SSW, WNW - ESE and ENE - WSW minor trends. The trends of the inferred lineaments are generally consistent with those of the magnetic anomalies in the study area. [ABSTRACT FROM AUTHOR]

This work is among the few studies conducted in Musawa sheet 56 NE, which is part of the basement complex rocks of TudunWulli - Kankia area. The study area lies between Latitude 12° 19' 00" to 12° 23' 00"N and longitude 7° 42' 00" to 7° 46' 00"N. Due to the continuous play of geologic processes on the earth, there is the need to continuously update the geology of the Nigeria basement complex as this has a very important economic implication especially in areas like mineral and groundwater exploration. Equally, less attention has been given to this sheet unlike other sheets within the zone. The study done in this area has revealed the various rock types and their geological characteristics: fieldrelation, macroscopic andmicroscopic features as well as structural elements. Results from the study shows that the area consists of granite, migmatitegneissandquartzite whichalldisplaya varietyofcolors, texturesandmineralogy. Carefulanalysis of the distinctive mineralogy, textures, optical and structural characteristics led to the nomenclature of the rocks. The migmatite-gneiss display two petrographic varieties base on their foliation: one with linear foliation of alternating light and dark color minerals, and the other with wave like foliation. While granite is generally fine to medium grained in texture. The dominant structural trend of joints and faults in the study area are NNE-SSW and NW-SE. All these trends are consistent with the general trends of the Nigeria basement rocks. A study of thin sections of the rocks under a petrological microscope reveals optical properties peculiar to each rock type. The type and nature of structural elements associated with the rocks together with their geometry reveal that the rocks have undergone more than one deformational event. The occurrence of numerous brittle and ductile structures shows that the area has a great potential for groundwater and mineralization. But the area still experience shortage of water for domestic purposes. [ABSTRACT FROM AUTHOR]

This paper presents the geophysical investigation for groundwater at Gbongudu area, Akobo Ojurin, Ibadan, Southwestern Nigeria. The area is underlain by the crystalline basement complex rocks and accessibility to potable water especially in the dry period of the year has been a major challenge. The Vertical Electrical Sounding using the Schlumberger configuration was employed. Twelve (12) vertical electrical sounding points were established in order to delineate the geo-electric layers in the area as well as evaluate the groundwater potential. The results are presented as profiles, geologic sections, curves, and maps. The VES results revealed a maximum of five geo-electric layers, viz: topsoil/lateritic sand, shale/clay, weathered layer, fractured basement and fresh basement respectively. Geo-electric sounding results were critically analyzed and interpreted. The yields of wells dug in most of these locations may be insufficient, even for domestic use because of its relatively small thicknesses. However, at a depth of 9.1 m a fracture zone occurs in VES 6 with resistivity value of 17.8 Ωm suggesting the presence of groundwater. Groundwater potential in this area is low on the average with VES 6 and VES 7 considered to be the main aquifer units suitable for groundwater exploration. Keywords: basement complex, electrical sounding, groundwater, exploration, aquifers