Southern Bida Basin Research Articles

Assessment of the Crustal Thickness within Southern Bida Basin and Surrounding Basement Rocks, North Central Nigeria, using Gravity Data

The crustal thickness within the Southern Bida Basin has been determined using Bouguer Gravity Data. This study focuses on a region situated in the southern part of the Bida Basin, a significant inland sedimentary basin in North Central Nigeria. Two distinct methods were employed to estimate crustal thickness from Bouguer anomaly values: (i) an empirical relationship between crustal thickness and Bouguer anomaly, and (ii) spectral analysis of the radial wave number. The average crustal thickness was derived by averaging results obtained from both methods. Additionally, a linear equation (HC = 34.39 – 0.17BG) was formulated for the study area, enabling straightforward determination of crustal thickness from any given Bouguer anomaly value. The estimated crustal thickness in the study area ranges from 32 km to 40 km, aligning closely with the overall crustal thickness of Nigeria as reported by Daniyan et al. (2002). The tectonic stability of the study area, situated on the stable African plate, further underscores its significance within the broader geological context of Nigeria.

Outcrops as windows to petroleum systems: Insights from the southern Bida Basin, Nigeria

The study assessed petroleum systems in the southern Bida Basin, Nigeria, focusing on the Cretaceous sediments. Reservoirs comprise Lokoja and Patti Formation sandstones, while shales, claystone, and siltstone serve as source rocks and stratigraphic traps/seals. Detailed studies delineating the key elements of the petroleum systems in the basin have not been conducted due to a lack of subsurface data. The goal of the current study was to use field observations, Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and geochemical and geomechanical data to evaluate key components of petroleum systems in the southern Bida Basin. The results presented in this investigation are intended to attain specific objectives, especially those lacking in the basin's study sections. Petrophysical analysis revealed that the Lokoja Sandstone has porosity of 37%–39.5% and moderate permeability of 23.22–42.29 mD. The Patti Formation sandstone reservoirs exhibited high porosity (38%–42%) and moderate to good permeability (31.54–66.48 mD), suggesting good potential reservoirs. SEM results revealed intragranular pores and micro-fractures in the Patti Shale, whereas the sandstone reservoirs in the Lokoja and Patti formations displayed fractures, facilitating hydrocarbon migration. Quartz was the dominant mineral in the sandstone units of both formations. XRD analysis revealed that brittle and clay minerals influenced the microstructure of Patti Shale. Geochemical analysis indicated promising petroleum potential in the Patti Shale, with a total organic carbon (TOC) content of 1.87 wt%, free hydrocarbon from kerogen (S1) of 0.41 mg/g, hydrogen index (HI) of 0.75 mg HC/g TOC, and production index (PI) of 0.17. The Patti and Lokoja formations' shale, claystone, and siltstone exhibited sealing potential, with a plasticity index of 24–35 and coefficient permeability of 2.8 × 10−4- 3.6 × 10−4 cm/s. Field studies, XRD, geochemical data, and geomechanical index values have confirmed the key components of the petroleum system, which in turn facilitate hydrocarbon generation, migration, accumulation, and entrapment in the basin.

GEOCHEMICAL, MINERALOGICAL, AND PETROGRAPHICAL STUDIES OF IRONSTONES AROUND MOUNT PATTI, SOUTHERN BIDA BASIN, NIGERIA: IMPLICATIONS FOR QUALITY ASSESSMENT, PROVENANCE AND ENVIRONMENT OF DEPOSITION

The mineralogical composition, geochemistry, and depositional environment of the ironstone exposed on Mount Patti in the southern Bida Basin of Nigeria were assessed using integrated geochemical, mineralogical, and petrographic techniques. X-ray fluorescence spectrometry, X-ray diffraction, and transmitted light microscopy were used in geochemical, and petrographical investigations of fourteen representative ironstone samples. Average chemical analysis results showed that the concentrations of SiO2 (5.93 wt%), TiO2 (0.09 wt%), Al2O3 (10.76 wt%), and Fe2O3 (77.47 wt%) were as follows. The ironstone may be found in a shallow marine environment or non-marine environment if the concentrations of CaO, Na2O, K2O, MnO, and CuO are less than 0.40. This assertion is supported by the absence of sulfur oxide (SO3) in the examined samples and the bivariate plot of SiO2 versus Al2O3 and triangular plot of Fe-Mn-(Cu+Zn). Low levels of CaO and the absence of CO3 indicate that the environment is oxidizing. The iron's grade was calculated and found to be approximately 54.180%, which has been classified as low grade. The study also revealed that the ironstone contains a high amount of gangue materials (Al2O3 and P2O5), its silica (SiO2) content is within permissible limits, and it is devoid of harmful materials like sulfur. Based on petrographic studies, the floating contact displayed by the framework grains indicates that the iron cements were eodiagenetic in origin. Although it can be used more effectively as cast iron, sufficient beneficiation (to remove excess silica) can make it useful for iron and steel production.

Revised stratigraphic sequence and type sections of the Southern Bida Basin, Nigeria

A reassessment of the stratigraphy of the Southern Bida Basin has been attempted among various disagreements. For this work, field geological mapping and stratigraphic descriptions of exposed lithologic types on outcrop sections were used. Section-by-section descriptions of important outcrops based on field observations aided in identifying lithologic units and delineating the boundaries of the sub-basin's three formations (Lokoja, Ahoko, and Agbaja). The type sections for formations in the sub-basin were not properly erected, so Jones (1958) type section has been supplemented by a more comprehensive hypostratotype, and the name Patti Formation, which is considered a misnomer in this context, has been replaced with Ahoko Formation proposed by Rahaman et al. (2019). Ahoko village is the type locality. The Agbaja Plateau, where the Agbaja Formation is best exposed, has been presented as the lectostratotype for the formation, while the revised stratigraphic succession of the Lokoja region shows the Lokoja Formation directly encompassing the Paleozoic Basement terrain, with the Maastrichtian Agbaja and Ahoko Formations (former Patti) overlying it sequentially.

Subsurface Structural Characterization as Deduced from High-Resolution Aeromagnetic Data over The Confluence Zones in Central, Nigeria

This study aimed to delineate the intrusion body that controls the structural setting and formation around the river Niger-Benue confluence zone with particular attention to its solid mineral potentials, this is achieved in mapping subsurface structural features through the analysis of recent high-resolution aeromagnetic (HRAM) data-sets with the purpose of examining their effects on geological structures that characterize the confluence zones from the study area. To obtain the necessary reduction in geomagnetic variation, measurements of regional gradients and time variation were used. After applying the reduction to the magnetic equator (RTE) to the corrected magnetic data that was obtained from the Nigerian Geological Survey Agency, NGSA, it was possible to determine the regional expansions of subsurface structural units for both qualitative and quantitative interpretations. In addition, the edge detection method is used to depict the structures and buried subsurface anomalies. Different handling processes were applied to the (HRAM) data, such as local wavenumber (SPI), power spectrum analysis, and Euler and Werner deconvolution analysis. The RTE magnetic anomaly caused by local structures and anomalous body delineated six sub-basins with low amplitude response, which agrees with the total gradient anomaly (analytic signal) and tilt of angle derivative that clearly outlined and characterize edges of lithostratigraphic of Niger-Benue river confluence zones. The sub-basin delineated are the southern Bida basin and northern Anambra basin. The source parameter imagings as well as the Euler and Werner deconvolution were used to delineate major subsurface structures and determine their source depth. Results showed that the area was affected by different lineament trending NE-SW, E-W, and S-E trends. Directional analysis indicates that the dominant trend agrees with the regional fault orientations. The estimated depth to the top of the lineaments on average varies from 0.3 km to 4.6 km and it is relatively deeper in the basins compared to the surrounding areas giving clues to the amount of sediment infill. A 2D forward model showed a sedimentary thickness ranging from 1 to 7 km, and this estimated depth is consistent with the average of 3.5 km proposed by previous researchers.

Sedimentary facies, paleoenvironments and paleogeography of the Upper Cretaceous succession in the southern Bida Basin, Nigeria

Sedimentary facies, paleoenvironments and paleogeography of the Upper Cretaceous succession in the southern Bida Basin, Nigeria

Facies analysis and sedimentology of the Campanian–Maastrichtian sediments, southern Bida Basin, Nigeria

Facies analysis and sedimentology of the Campanian–Maastrichtian sediments, southern Bida Basin, Nigeria

Empirical modelling of geotechnical strength based on index properties: a case of patti formation, southern bida basin, nigeria

The strength properties of geo-materials are paramount to the stability or otherwise of civil engineering structures. However, the determination of some of these properties such as California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) is costly and time-consuming. This necessitates the generation of models that can quickly predict the strength properties from cost-effective and less time-consuming index properties of the same geo-materials. In this study, an attempt has been made to predict the CBR and UCS values from Atterberg limit tests for sediments derived from Patti Formation, Southern Bida Basin, Nigeria. The tests were performed following appropriate codes of the British Standard Method for testing materials. Both linear and polynomial fitting models were employed for regression analysis between the index and strength parameters. The results showed that Liquid Limit (LL), Plastic Limit (PL), and Shrinkage Limit (SL) are strongly correlated with UCS and CBR, having R2 ranging from 0.8-0.91. The equations can be used to quickly predict UCS and CBR in areas with similar geology. Similar studies are recommended in other parts of the country to aid the regional evolution of models for rapid strength characterization of geo-materials.

Facies, textural and geochemical evaluation of the post-Santonian sandstones in the Bida basin, Nigeria: Implications for control on hydrocarbon sandstone reservoir characteristics and paleoenvironments

Using a combination of field observations, textural analysis, scanning electron microscopy (SEM), mineralogical X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and thin-section analysis, the hydrocarbon and paleoenvironmental characteristics of the Cretaceous sandstones of the southern Bida Basin, Nigeria, were evaluated. SEM data were used to display the mineral morphology, degree of cementation and presence of clay minerals on the grain surfaces and their pores on both sandstones of the Patti and Lokoja formations. The lithofacies analyses revealed three distinct facies associations. The XRD data showed that for the Lokoja and Patti sandstone reservoirs contained quartz from 49 to 67% and 43–68%, respectively. The XRF data also showed that both formations' sandstone reservoirs have a high percentage of silicon and low aluminum content. The grain size study showed that the Lokoja sandstone reservoirs include medium-coarse sandstone (−0.63 to 1.30 ф) that are poorly-moderately sorted (0.72–1.82 ф). In contrast, the Patti Formation is primarily made up of fine-medium sandstones at investigated outcrops, which typically display reasonably good to poor sorting (0.70–2.53 ф). The skewness of the sandstone reservoirs ranged from fine to coarse, and their kurtosis ranged from very platykurtic to leptokurtic. The research area's predominant depositional environments include shoreface/foreshore, estuary mudflat, and estuarine delta with fluvial interference, according to an analysis that combined sedimentary facies and textural data. This demonstrates that the sandstones from the two units have moderate quality prospective hydrocarbon reservoirs based on their physical and chemical characteristics.

Field and Sedimentological Studies of Nataco-Banda Sediments of Lokoja Formation, Southern Bida Basin, Nigeria: Implication for Depositional Environment

The study area falls within the Lokoja Formation of the Southern Bida Basin. The objective of this study was to evaluate the field characteristics and sedimentological parameters of depositional environment of the Nataco-Banda Sediments of Lokoja Formation, Southern Bida Basin, Nigeria using appropriate techniques such as granulometric and pebble morphometric analysis. Field studies revealed a repeated alternating sequence of conglomeratic and pebbly to coarse-grained sandstone and overbank fine sediment that is indicative of a braided fluvial source while the presence of crossbedding is suggestive of tidal influence. The morphometric analysis shows a fluvial setting where pebbles plot in the river area than the beach area. Environmental discrimination formulae for Y1, Y2 and Y3 indicated the dominance of Beach and Shallow agitated marine in both Y1 and Y2, respectively, while the almost equal percentage values of Y3 in both fluvial and shallow marine settings are highly suggestive of a shallow marine environment that is largely influenced by fluvial deposition.

Hydrocarbon prospectivity of the southern Bida and northern Anambra basins, Nigeria using palynological and geochemical studies

• Hydrocarbon prospectivity and depositional environments of two basins. • Integrating palynological and geochemical data in evaluating hydrocarbon potential. • Identifying the depositional environments of the basins. The palynological and geochemical analyses were carried out on shales samples in borehole and outcrop sections of the southern Bida and northern Anambra basins respectively. These analyses aimed at evaluating the hydrocarbon prospectivity of the basins. The results of total organic carbon (TOC) of 0.30–9.01 wt% in Patti Shale interval of Agbaja section in southern Bida Basin revealed a high TOC, depicting a substantial organic matter in the source rock. TOC of 0.82–2.56 wt% for Patti Shale in Ahoko outcrops (southern Bida Basin) show relatively moderate TOC which revealed a fair organic matter in the source beds. TOC of 0.44–0.95 wt% of Mamu Shales in Ojodu outcrops in northern Anambra Basin indicates a moderate to poor TOC which suggests fair to poor organic matter in the source rock. Hydrogen Index (HI) range of 45- 153 mgHC/grock with producible hydrocarbon (S 2 ) of 2.60–5.00 mgHC/grock reveals very good source rock potentials in the Agbaja section. HI of 0.08–0.57 mgHC/grock, S 2 of 0.12 mgHC/grock in Ahoko and HI of Mamu Shales of 30–136 mgHC/grock, S 2 of 0.14–0.90 mgHC/grock in Ojodu outcrop, both revealed poor to fair source rock potentials. The results of vitrinite reflectance (Ro) and maximum temperature (T max ) range (0.30 to 0.55% and 420 to 435 °C, respectively) suggest a low to relatively high thermal maturity index in both frontier basins. The thermal maturity of the shales in Agbaja borehole sections is moderate to high, although from record no petroleum has been produced from the sections in the basin. From the organic matter type, the kerogen is classified as type II/III and IV for both basins. The palynological results propose the Maastrichtian age for both basins, regarding the rich accumulation concerning micro-florals; Psilatricolporites prolatus, Florentinia laciniata seghiris, Echitriporite trianguliformis, Arecipites sp. Monoporite, Triporites . Dinocysts belonging to the Spiniferites, and Deflandreacean dinoflagellate, and Acritaarchs of Polipodiaceosporite retigularis, Acripite sp., which were analyzed from the shale intervals in the basins; suggest a Cretaceous age, marginal marine-continental environments, paleovegetation, and humid climate. Finally, the palynological, and geochemical analysis results will contribute knowledge that will be useful for hydrocarbons exploration in these frontier basins in Nigeria.

Source Area Weathering and Tectonic History Inferred from the Geochemistry of the Maastrichtian Sandstone from Patti Formation, Southern Bida Basin, North Central Nigeria

Sandstones sampled from Patti Formation, Southern Bida Basin, were studied geochemically using Inductively Coupled Plasma Atomic Emission Spectrophotometer (ICP-AES) and an Inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique to evaluate their weathering and tectonic setting as well as to deduce the paleo-climatic conditions that existed during their deposition. Geochemically, SiO2 range from 73.9% to 86.2%, Al2O3 (6.7%~17.1%), Fe2O3 (1.1%~1.9%), K2O (0.1%~0.7%) while MgO, CaO, Na2O, P2O5, MnO and TiO2 were <1%. Enriched in Ba (Av. 622.94), Sr (Av. 153.63), Rb (Av. 55.08) and Zr (Av. 51.86) relatively similar in composition to UCC. High SiO2 but low other major oxides signify high mobility during processes of weathering. This was confirmed by high value (>80%) for indices like chemical index of alteration, chemical index of weathering, plagioclase index of alteration, mineralogical index of alteration and relatively lower values for weathering index of parker, recently used alpha indices (αAl E) of sodium (326.17αΑl Na<344.40), magnesium (100.54αΑl mg<398.55), calcium (12.07αΑl Ca<198.99), potassium (4.43αΑl K<64.33), strontium (0.84αΑl E<21.40), barium (0.45 αΑl Ba<10.52) and rubidium (0.0008αΑl Rb<0.06), supported by AI2O3-(CaO*+Na2O)-K2O and CIA vs. SiO2 plots that imply intense weathering in the source area. The obtained high CIA values (>80) indicates a steady-state of weathering under a warm/humid climate as confirmed by the SiO2 vs. Al2O3+ K2O + Na2O plot. High average SiO2 (75.41wt%) with K2O/Na2O ratio >1 (15.63), low Fe2O3 (1.27wt %), Al2O3 (15.82wt%) and TiO2 (0.46) suggest passive margin tectonic setting. This is supported by enriched ΣREE (209.64 ppm), ΣLREE (195.78), LREE/HREE (27.78) and negative Eu/Eu* (0.68), plots of log (K2O/Na2O) vs. SiO2 and SiO2/Al2O3 vs. K2O/Na2O. Major elements discriminant-function multi-dimensional diagram, DF1 (arcrift-col) vs. DF2 (arc-rift-col), for high-silica sediments revealed a continental rift tectonic setting. Thus, the Patti Formation sandstone underwent a high degree of weathering under a humid climatic condition within a continental rift tectonic setting.

Sedimentary facies and textural characteristics of Cretaceous sandstones in the southern Bida Basin, Nigeria: Implication for reservoir potential and depositional environment

A study of sedimentary facies, mineral and textural characteristics of sections of conglomerates/pebbles and sandstone facies found within the Lokoja and Patti Formations in southern Bida Basin, Nigeria, is carried out to evaluate the paleo-environment and reservoir quality of the sandstones of the formations through field observations and textural and mineralogical (using X-Ray Diffractogram) analyses. Nine lithofacies are identified and grouped into three main facies associations. These sedimentary facies suggest deposition in both foreshore and estuaries. The mineral analysis (XRD) shows that the quartz content in sandstone facies of the Lokoja Formation ranges between 49% and 67%, and that of the Patti Sandstone between 43% and 56%, indicating a quartz dominance. The granulometric studies reveal that the Lokoja Formation comprises coarse-to medium-grained (−0.63 to 1.30 φ) sandstone with moderate-poor sorting of 0.72–1.82 φ. On the other hand, medium to fine-grained sandstones dominate the Patti Formation, which is averagely poorly sorted (1.29–1.54 φ). The sandstones are coarsely skewed to finely skewed, with the kurtosis ranging from very platykurtic to leptokurtic. Morphological results of the pebbles from both Lokoja and Patti Formations indicate that the study areas are mainly characterized by the interplay of both wave and fluvial processes, which suggests that the environment of deposition of sandstone facies is predominantly of the fluvial to the shallow marine environment with the indication of tidal influence.Integrating sedimentary facies and textural results suggests subtidal sand ridge/foreshore, estuarine mudflat, and estuarine delta environments with fluvial influences. Evidence from the textural and mineral characteristics indicate that the sandstone facies of the Lokoja and Patti Formations are fairly matured and can act as potential hydrocarbon reservoirs in the formations. The facies, XRD mineral, and textural results have revealed potential hydrocarbon reservoir areas and paleo-depositional features of the Lokoja and Patti Formations.

Petrography and Heavy Mineral Studies of Lokoja Formation along Mount Patti North Central Nigeria: Implication for provenance Studies

The Southern Bida basin consists of the Lokoja, Patti, and Agbaja formations. This study focuses on the Lokoja formation and samples gotten were used for petrography and heavy mineral analysis. Results of all analytical techniques employed in the study are presented here. A critical assessment of each set of results and their integration aided the proper interpretation and useful discussion. This study focuses on the Southern Bida Basin, specifically the Lokoja Formation because the exposures of Patti are poorly exposed. Outcrop samples were obtained from the exposed sections of the study area in Kabawa and Robinson street respectively. Different features were observed, such as the thickness of the exposure, the nature of the lithology, color, and sedimentary structures. The dominant lithologies in the area include sandstone and ironstone. The sandy facies are generally arkosic characterized by poorly sorted very fine to conglomeratic sandstone sequence. Laboratory investigations of samples included petrography and heavy mineral analysis. Sandstone samples were collected from the study area. Each sample was divided into two parts: the first part for petrographic studies and the second part for heavy mineral analysis.

X- Ray Diffraction Studies of Patti Claystone Member of the Campano-Maastrichtian Patti Formation, Southern Bida Basin, North Central Nigeria

X-ray diffraction and field studies were carried out on the Patti Clay Member of the Patti Formation in the southern Bida Basin. The studies involved field collection of samples and XRD laboratory analysis of clay samples in order to determine the dominant clay type, subordinate associated minerals, geologic processes and paleoenvironment of deposition. Field study involved standard litho-description by noting textural properties, facies type, fossil presence, structure and diagenetic effect. Laboratory XRD analysis procedure included sample grinding, XRD recording condition, selection and measurement of reference minerals, quantification of clay minerals using XRD processing software, XPert-Highscore Plus to generate results indicating clay mineral type and other minerals peaks. Lithostratigraphic section is dominated by the alternation of sandstone and claystone layers. The sedimentary structures are planar parallel and cross bedding in nature. The sandstone at Ahoko and along Lokoja-Abuja highway is characterized by liesegang ring and bioturbation structures. XRD results indicated that the Patti Clay Members are dominated by kaolinite with subordinate illite, montmorillonite and zincite in rare cases. The clay members were suggested to be deposited by moderate to low energy of transportation, moderate to low rate of deposition through prograding mechanism in a marginal marine setting. The kaolinite clay was formed by meteoric water reaction with the shallow-seated clay members through leaching of K+, Na+ and silica ions with resultant kaolinite stable at adequate pH that was not acidic.

Mineralogy and geochemistry of the sandstone facies of Campanian Lokoja formation in the Southern Bida basin, Nigeria: implications for provenance and weathering history

The upper Cretaceous Lokoja Formation is the earliest deposited stratigraphic unit in the intracratonic Bida Basin, Nigeria. It consists predominantly of sandstone and offers a potential hydrocarbon reservoir in the basin. In this study, we investigated the bulk elemental (major, trace and rare earth elements) and mineralogical compositions of the sandstones for the determination of their compositional maturity, tectonic setting, source and weathering history. The sandstone geochemical data indicates that the samples contain moderate amount of SiO2 and Al2O3 with average values of 78.3 % and 9.75 % respectively. Relatively high average values of K2O (1.59 %) and Na2O (1.52 %) and low Fe2O3 (2.56 %), MnO (0.05 %), TiO2 (0.31 %) and P2O5 (0.018 %) were obtained. Plots of relevant geochemical elements reveal that the sandstones are predominantly arkose and litharenite types with minor sub-litharenites. Application of some trace element geochemical proxies; La/Co (11.78), Th/Co (1.32), La/Th (7.04) and Eu/Eu∗ (0.82) to constrain the source history suggest protolith dominated by felsic rock. Relatively low average values of ΣREEs (12.81) and ΣHREEs (1.52) support the felsic provenance of the sandstones and the tectonic setting discriminant function plots indicate passive margin depositional basin. Paleo-weathering plot reveals a moderate humid climatic condition and the mean values of CIA (79.21), CIW (90.51), PIA (66.55) and A–CN–K diagram indicates low to moderate chemical weathering in the source area and compositional immaturity for the sediments. This study concludes that the sandstones of the Lokoja Formation are immature and were derived from the faulted blocks of granitic basement rocks at the margin of the basin and deposited proximally.

Sedimentary facies and environments of the sedimentary fill of Southern Bida Basin, Nigeria

Six lithofacies were identified in the Lokoja Formation, Southern Bida Basin: fanglomerate/ conglomerate lithofacies (Gmc), fine to coarse-grained ferruginized weakly cross-bedded, pebbly sandstone lithofacies (Scx), fine to coarsegrained sandstone lithofacies (Sfc), silty claystone lithofacies (Csm), siltstone lithofacies (Slt) and lateritic ironstone lithofacies (Ilt). These were grouped into three lithofacies associations viz: alluvial fan, braided river channel, floodplain lithofacies association. Nine lithofacies were identified in the Ahoko Formation. These are: black-dark grey carbonaceous shale lithofacies (Shc), bioturbated ripple-laminated siltstone lithofacies (Sbr), poorly cross-laminated claystone lithofacies (Cxl), concretionary/nodular ironstone lithofacies (Icn), medium to coarse-grained sandstone lithofacies (Smc) fine grained, well-sorted, friable bioturbated herringbone cross-bedded sandstone lithofacies (Sxf), massive brownish claystone lithofacies (Clm), massive claystone with lateritic ironstone lithofacies (Cli) and lateritic ironstones lithofacies (Ilt). These have been grouped into three lithofacies associations viz: shallow marine lithofaciesassociation, tidal-intertidal flat lithofacies association and floodplain lithofacies association. Similarly, three lithofacies were identified in the Agbaja Formation and have been grouped into two lithofacies association. These are: fine to medium-grained sandstone ironstone interbedded lithofacies (Sti), oolitic–pisolitic ironstone lithofacies (Iop) and concretionary ironstone lithofacies (Icr). The lithofacies associations are: tidal-intertidal flat lithofacies association and shallow marine lithofacies association. Result of lithofacies analysis helped in interpreting the depositional environments. The Lokoja Formation is a product of a fluvial dominated alluvial system from debris/gravity flow in alluvial fan. This developed further into braided river channels and later meandering river during the closing stages. Sediments of the Ahoko Formation were deposited in tidal/intertidal flats and shallow marine environments while sediments of the Agbaja Formation were produced by a shallow marine system with a high tidal influence.

Mineralogical studies of the Maastrichtian Gerinya Claystone of the Patti Formation, southern Bida Basin, Nigeria: Implication for industrial application

Abstract The mineralogical compositions of the Gerinya claystone, Patti Formation, Southern Bida Basin, Nigeria, were investigated to infer their sedimentological process and industrial application. Mineralogical analysis of the claystone was carried out using the X-ray diffraction (XRD) method. The diffractogram peaks aided the identification of the clay and non-clay minerals in the study area. The XRD showed kaolinite as the major clay mineral with compositions ranging from 10.8 - 67.6 wt%. The non-clay minerals were quartz, anatase, diopside, goethite, hematite, rutile, muscovite and micro-cline. Among the non-clay minerals, quartz had the highest percentage mineralogical composition of 21.2 to 83.4 wt%. The mineral assemblage is typical of a hot and humid climate where chemical alteration and hydrolysis of silicate minerals are severe. The sediments are of mafic and felsic crystalline rocks origin. The sediments are of low energy floodplain/interchannel depositional environment. The Gerinya claystone vary from low to high porosity and very low to low permeability. The claystone can be used as clay liners and as raw material for ceramic production. The application of the claystones in fertiliser production will require some processing. The clay-stone can be used for haemorrhage control in the pharmacological/medical sector. Although, the ingestion of the clay-stones could lead to dental damage and possible perforation of the sigmoid colon in the gastrointestinal tract.

Petrographic Studies, Heavy Mineral Analysis and Pebble Morphogenesis; Implications for Sedimentary Processes of Southern Bida Basin, Nigeria

Petrographic Studies, Heavy Mineral Analysis and Pebble Morphogenesis; Implications for Sedimentary Processes of Southern Bida Basin, Nigeria

Petrographic and geochemical interpretations of source provenance and tectonic setting of the Lokoja Sandstone, Bida Basin, Nigeria

The petrography and geochemistry of major and trace elements distribution pattern for the Lokoja Sandstones, Southern Bida Basin, Nigeria; were used to interpret their provenance, weathering conditions and paleotectonic setting. A total of seven (7) representative sandstone samples were selected for petrographic, heavy minerals and inorganic geochemical analyses; that is X- ray diffraction (XRD), X-ray fluorescence (XRF) and Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Results of the petrographic analysis showed 52.14 % quartz, 39.29 % feldspar, 2.00 % rock fragments, 5.14 % matrix and cement fraction as well as 1.43 % unfilled voids. Results of major elements and oxides suggests intermediate to felsic source rocks while the dominance of Na-rich feldspar to the k-feldspar and high value of Fe2O3+MgO shows contribution from ferromagnesian minerals of mafic igneous source provenance and oceanic island arc region. Average concentrations of designated trace elements in the studied sandstones are low in concentrations. The lower concentrations of Cr, Co, and Ni and higher concentrations of Zr, Ba, and Sr suggest a felsic progenitor rock. But significantly high values of Ni (7.02 ppm), La/Co (7.99), and Ni/Co (3.28) as well as the low concentration value of Y, (3.23 ppm) suggests contributions from mafic source rocks. Low average ratios for La/Co, Th/Co, Th/Sc, Ni/Co, Cr/Ni, Cr/Sc, Cr/Th, Ni/Co, Cr/Ni, Cr/Th, Cr/Sc, Th/Sc, La/Co and Th/Co also suggest a felsic source provenance. An average CIA value of 78.04% is indicative of an intense recycling in the source area while an average MIA value of 56.13% suggests a moderate degree of weathering. The high clay matrix and feldspar content have been used to classify the sandstones as feldspathic greywackes deposited in dry arid climatic conditions under a basement uplifted tectonic setting.  Â