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- ItemGeothermal parameter assessment in the Southwestern Sokoto Basin, Nigeria, using spectral analysis (centroid method)(Nigerian Society of Physical Sciences, 2024-06-12) U. Z. Magawata, N. K. Olasunkanmi, T. A. IssaThis study utilized spectral analysis (centroid method) to assess geothermal parameters in the southwestern part of the Sokoto Basin, Nigeria. The high-resolution airborne data comprised forty-nine (49) overlapping blocks, and each block was divided into 55x55 km to evaluate essential parameters such as depth to the top boundary (Zt), centroid depth (Zo), and magnetic source bottom (Zb = 2Zo-Zt). The analysis revealed variable Curie points depths (CPD), ranging from 3.89 km to 26.56 km. The lowest CPD is primarily associated with basement rocks within anomalies A, B, C, D, E, F, G, H, and I, with an average CPD of 9.16 km. Furthermore, the thermal gradients ranged from 21.84 ◦C/km to 149.10 ◦C/km, with an average thermal gradient of 73.30 ◦C/km. The heat flow exhibited variations between 54.81 mW/m²and 374.24 mW/m², with average heat flow of 180.4 mW/m², indicating significant geothermal potential zones. The high thermal gradients and heat flow regions were identified, around anomalies A, B, and C. Additionally, temperature gradients identified at shallow depths ranged from 110 ◦C/km to 150 ◦C/km. The results reveal the presence of high-temperature points and anomalous geothermal potentials, particularly within anomalies A, B, and C, thus requiring further investigation for sustainable geothermal energy generation in the study area.
- ItemGeochemistry and Mineralogy of Maastrichtian Coals from the Anambra and Gongola Basins of Nigeria: Implications for Coal Quality, Resource Potential, and Agglomeration Characteristics(Journal of Economic Geology, 2024-06-22) Ayoola Yusuf Jimoh; Mariam Bolaji; Jimoh Ajadi; Shakirat Mustapha Aminu; Mutiu Adelodun AkinpeluAnambra and Gongola basins are part of the sedimentary inland basins in Nigeria characterized by fossil fuels and in response to its present energy problem, Nigeria has shifted its power generating focus to coal. The studied coals were obtained from two localities, namely Ankpa and Maiganga in Kogi and Gombe States, respectively. The coals were investigated to determine its quality in terms of use and resource potential. The coals were analyzed by proximate, ultimate, elemental, mineralogy and scanning electron microscopy-energy dispersive spectrometry analyses. The objectives of the study are to determine the coals cokability, rank, paleoenvironments, hydrocarbon potential, and slagging tendency. The average values of moisture content, ash, volatile matter, and fixed carbon are 5.54%, 16.42%, 48.45%, and 30.71%, respectively, for Ankpa coals, while Maiganga recorded 10.68%, 8.60%, 44.33%, and 36.41%, indicating high volatile sub bituminous non-coking coals that are optimum for combustion and electric power generation. The Van Krevelen plot based on the H/C vs. O/C showed Type IV kerogen. The XRD results, correlation plots, and Detrital Authigenic Index (DAI) values of 7.49 and 13.49 in Ankpa and Maiganga coals, respectively, indicated that Ankpa coals are enriched in authigenic minerals like quartz, pyrite, and calcite, while kaolinite and quartz were probable detrital minerals in the Maiganga coals. The agglomeration of the coals deduced by Base/Acid (B/A), Silicon ratio (G), Silica/Alumina (S/A), Iron/Calcium (I/C), Carbon/Hydrogen (C/H), and Fixed Carbon/Volatile matter (FC/V) showed weak–medium-strong for the Ankpa coals and strong for Maiganga coals
- ItemShear Sense Analyses of Basement Complex Rocks in Parts of SW Nigeria(International Journal of Earth Sciences Knowledge and Applications, 2022-02-04) Olufemi S. Bamigboye, Toba E. Bamidele, Adeonipekun D. Adedoyin, Taofeeq A. Issa, Omolayo A. OmorinoyeThe study area, Oko/Olla is part of Osi sheet 224 southwest and falls within the Basement Complex of South-Western Nigeria. Field and petrological studies revealed that the area is underlain by metamorphic complexes and late intrusives which include: migmatite, granite gneiss, porphyroblastic gneiss, banded gneiss, fine grain granite, diorite with aplite and pegmatite occurring as intrusions. Migmatite is the dominant rock within the study area. The petrogenetic affiliation of the rocks as indicated by the rocks and mineral assemblage represented by plagioclase +alkali feldspar +biotite ±muscovite ±hornblende in the quartzo-feldpartic rocks of the area, are suggestive of amphibolites facies of metamorphism. Kinematic markers which include folds, boudins, σ– and δ–type porphyroclasts, and strike-slip and dip-slip faults were used as shear sense indicators. Detailed analysis of folds revealed asymmetric fold shapes with preponderance of Z shape folds. The dominant Z–shape drag folds are consistent with the ductile and brittle dextral shear sense indicated by asymmetric boudins and porphyroclasts geometry. Structural analysis from this study indicates that the ductile fabric was overprinted by brittle deformations resulting from the uplift of the area to a low temperature-pressure conditions which is more favorable for brittle deformations. This over printing relationship is suggestive of continued movement of Olla and Oko areas after uplift of the areas during Pan African thermo-tectogenesis. It is therefore concluded on the basis of petrological evidences as well as clear overprinting relationships as revealed by decisive kinematic markers that although there are some sinistral and conflicting shear sense indicators in the area, dominant network of dextral ductile and brittle shear sense in the study area is consistent with the N-S regional structure in the Basement Complex of Nigeria.
- ItemSedimentological and geochemical evaluation of sandstones of the Ilaro formation, Dahomey Basin, Southwestern Nigeria: Insights into paleoenvironments, provenance, and tectonic settings(Journal of Nigeria Social and Physical Science, 2024-02-29) Jimoh, Ayoola Yusuf; Saadu, Mariam Bolaji; Adetoro A.A; Ajadi, Jimoh; Issa Ayinde Taofeeq; Issa UmarGrain size analysis, geochemistry, and petrography of sandstones of the Ilaro Formation exposed at the Ajegunle area were investigated to infer provenance, transportation history, tectonic setting, paleoenvironment, and degree of palaeoweathering of the sediments. Selected sandstones were analyzed, and the major, trace, and rare earth elements were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results from the granulometric analysis showed that sandstones were deposited in fluvial conditions. The sandstones exhibit a coarse-grained texture, displaying poor sorting and being texturally immature. The petrographic analysis indicated that quartz was predominant, whereas opaque minerals, muscovite, and ferruginous ground mass were present in smaller quantities. The sandstones can be geochemically classified as arkose and subarenite. The sandstones have an average composition of SiO2 (82.87%) and Al2O3 (9.49%), while K2O, Na2O, MgO, CaO, and P2O5 have <1% each. The elevated Al2O3 content is associated with the lithic fragment composition, whereas the low concentrations of MgO (mean 0.03%), Na2O (mean 0.008%), and K2O (mean 0.04%) suggest chemical destruction in an oxidizing environment. The angularity of the grains indicated a short transportation history very close to the provenance. Bivariate and discriminant plots from major elements and trace elements suggest the sandstones were non-marine and sourced from intermediate rocks. The sandstones were deposited in an oxic-dyoxic condition under a humid climate and passive or active continental margins. The average values of the weathering indices indicate an intense degree of chemical weathering.
- ItemSubsurface investigation for pre‑foundation study utilizing integrated geophysical and geotechnical methods, UNILORIN campus(Discover Geoscience, 2024-12-30) Gabriel Efomeh Omolaiye · Abdulhameed Kayode Oniyangi · Taofeeq Ayinde ISSA · Sodiq Bamidele AdamThis study involves subsurface investigation of a proposed site within senior staff quarters at the University of Ilorin campus utilizing the electrical resistivity technique, magnetic method and geotechnical analysis for the pre-foundation study. The land magnetic survey was acquired at 20 m spacing along seven traverses with the use of Geometrics G857 Proton Precession Magnetometer revealing the presence of concealed basement contact separating the biotite schist in the north from granite gneiss in the south. The Schlumberger configuration was used for the 1-D vertical electrical sounding (VES) technique, with the current electrode spacing (AB/2) varied between 1 and 100 m, which revealed three to four geo-electric layers which include lateritic/topsoil (93-3053Ωm, 0.3–2.5 m), clayey-sand (127-639Ωm, 1–13.2 m), weathered basement/sandy-clay (55-767Ωm, 3.6–33.3 m), and fresh basement (above 1000Ωm). WINRESIST and Surfer were used for the processing of resistivity data while Microsoft Excel was adopted for ground magnetic processing. However, the geotechnical analysis conducted on undisturbed samples picked at different depths from eight pits dug to a depth of 2.3 m revealed the following: bulk density (1.80 g/cm3-1.99 g/cm3), dry density (1.67 g/cm3-1.86 g/cm3) liquid limits (22.3%-34.1%), plastic limits (12.6%-19.8%), plasticity index (9.7%-14.3%) and cone penetration test (89.8 kN/m2-2110.3 kN/m2 at a depth of 0.1 m to 0.3 m), in which all these geotechnical analysis results classified the soil to be competent in variations and assess soil mechanical behaviour to support structural loads within study area. The integration of geophysical and geotechnical results revealed high topsoil resistivity correlates with high bearing capacity and is interpreted as thick and compacted lateritic materials.