Browsing by Author "Alabi, A. A."

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Characterization of Pegmatites in Ogodo-Odobola Area of Idah Sheet 267NW, Central Nigeria
(INTERNATIONAL JOURNAL OF SCIENCE FOR GLOBAL SUSTAINABILITY, 2023-07) Omanayin, Y. A.; Waziri, N. M.; Onoduku, U. S.; Alabi, A. A.
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. Keywords: Mineralization, Basement Complex, Structural Features, Petrography, Ajaokuta
COMPOSITIONAL FEATURES AND Ta-Sn-Nb RARE METAL MINERALIZATION POTENTIAL OF OGODO-ODOBOLA PEGMATITE, CENTRAL NIGERIA
(Nigerian Mining and Geosciences Society (NMGS), 59th Annual International Conference & Exhibition Book of Abstract, 2024-03) Omanayin, Y. A.; Waziri, N. M.; Onoduku, U. S.; Alabi, A. A.
Large pegmatite bodies are abundant in Ogodo-Odobola area. They occur in tabular forms and concordant to discordantly intruding the host rocks of migmatitic gneiss, schist and granite. This research is aimed at assessing the geochemical characteristics of pegmatite in the Ogodo-Odobola area to evaluate their rare metal potential. Field investigation was undertaken to determine the occurrences and relationships of the pegmatites with the host rocks. Thirty-three (33) fresh pegmatite samples were analysed using X-Ray Fluorescence (XRF), Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) and Inductively Coupled Plasma Mass Spectrometry (ICPMS) techniques at the National Geoscience Research Laboratory, Kaduna and the Activation Laboratories Ltd. (Actlab), Ontario, Canada respectively. Major oxides in the whole rock pegmatite show that they are of siliceous (SiO2; 72.82 wt.% average) and peraluminous (Al2O3; 16.78 wt.% average) composition. The K2O, Na2O and Fe2O3 contents average 4.81 wt.%, 3.13 wt.% and 1.27 wt.% respectively while CaO, MnO, MgO, TiO2 and P2O3 are each less than 1.0 wt.%. Average values of trace elements in the pegmatite are Ta (12.40 ppm), Sn (18.36 ppm), Nb (94.51 ppm), Be (16.14 ppm), Rb (480.23 ppm), U (12.47 ppm), Cs (17.14 ppm), Ga (39.91 ppm), Ge (3.91 ppm), W (4.81 ppm), Li (40.98 ppm), Mn (890 ppm) and B (18.96 ppm). Ratios of diagnostic elements of K/Rb (75.21 ppm), K/Cs (3348.39 ppm), Rb/Sr (25.55 ppm), Rb/Cs (37.18 ppm), Ta/W (2.78 ppm), Nb/Ta (8.81 ppm), Ba/Rb (0.07 ppm) indicate a moderate index of fractionation. A/CNK >1 and Al2O3>CaO+Na2O+K2O with enrichment of SiO2, Al2O3, Na2O, K2O and depletion of Fe2O3, MnO and MgO suggests that Ogodo-Odobola pegmatite is of peraluminous bulk composition and plots of A/NK versus A/CNK and Rb versus (Y+Nb) discriminates the pegmatite in the peraluminous Lithium-Caesium-Tantalum (Li, Rb, Cs, Be, Ga, Nb Ta, Sn, B, Ge, U, W) of syn-collisional to within plate granitic family. The plots of Ta versus Cs, Ta versus Ga, Ta versus (Cs+Rb) and Be versus K/Nb, with over 70 % of the samples plotting below the Beus line and 100 % below the Gordiyenko line reveal that the pegmatites from the study area are barren to marginally mineralized in rare metals (Ta>Sn>Nb). Keywords: Pegmatite, Siliceous, Peraluminous, Rare metal, Syn-collisional
Environmental Impact of Artisanal Gold Mining on Soils in Saigbe and Environs, Part of Minna Sheet 164, North-Central Nigeria
(Minna Journal of Geosciences (MJG), 2017) Omanayin, Y. A.; Abdurrahman, R.; Akande, W. G.; Mamodu, A.; Alkali, Y. B.; Alabi, A. A.
The environmental geochemistry of soils from Saigbe and environs, Minna, North-central Nigeria was studied in an attempt to assess the impacts of artisanal gold mining activity in Saigbe and environ. Geological fieldwork carried out in the area revealed that the underlying lithologies include schist, granite and amphibolite. A geochemical soil survey was also carried out and a total number of twenty (20) soil samples were systematically collected from both mined and unmined sites within the study area, of which eight (8) representative samples were geochemically analyzed. Elemental concentrations (major and trace elements) in the soil samples were determined using X-Ray fluorescence (XRF) technique. The physical impacts observed during fieldwork in the area include loss of vegetation, land degradation, water pollution and abandoned pits. The average concentrations of the elements determined were compared with the published upper crustal abundance of the individual elements and subsequently their enrichment ratios were computed. Elements such as Ag, Au and Hg show high enrichment with 1.81 ppm, 0.03 ppm and 0.11 ppm concentrations respectively. The result from accumulation index (Igeo) also shows possible Hg contamination. This potentially toxic element can cause serious damage to the skin, nervous and digestive systems in man through direct or indirect consumption.
GEOLOGY AND GEOCHEMISTRY OF PEGMATITES OF OGODO – ODOBOLA, NORTH CENTRAL NIGERIA: A STATUS REVIEW
(FUDMA Journal of Sciences (FJS), 2022-12) Omanayin, Y. A.; Waziri, N. M.; Onoduku, U. S.; Alabi, A. A.; Amadi, A. N.
Pegmatites are an extremely, coarse-grained igneous rocks of granitic composition, constituting of mainly large crystals of quartz, feldspar and mica. Their occurrence cut across various formations, but mostly around granitoids. They are known to host industrial, rare metals, exotic minerals and gemstones of economic value. Due to the continuous demands and recently discovered uses of some of these minerals, its continuous exploration can never be over-emphasized. Pegmatites occurrence in Nigeria were formerly confined to certain quadrants but resent research has proved they also exist in other zones too. Its occurrence in Ogodo-Odobola area is a recent discovery with scantily available literature. The Few available research work conducted on pegmatite of the Ogodo-Odobola area in Kogi State, North central Nigeria has been reviewed. The works focused on its feldspar content for economic value and the latter attempted the mineralization potential of the pegmatites. The area is revealed to be underlain by schistose and granitic lithologies and intruded by the pegmatite dykes of various dimensions. However, recent studies on granitic pegmatites have evolved just as the pegmatites, not only concentrating on their industrial potentials but also on rare metal mineralization potentials which presently are a key to unlocking the future technologically. A few of those relevant and recent studies in the field were also reviewed to bring forth new ways of dealing with this present world cake to geoscientists. White micas are a useful mineral for determining the degree of evolution in pegmatites. This was achieved in the research work using K/Rb ratios paired with incompatible elements such as Cs. Decreasing K/Rb and increasing Cs is a signs of increasing evolution. The modeling of fractional crystallization of white micas in pegmatites using these trace elements determined that the pegmatites are a result of 99% to 99.99% crystallization of a granitic melt. Keywords: Pegmatites, Ogodo-Odobola, White Mica, Kogi State, North Central, Nigeria
Preliminary Studies of Pegmatites of Ogodo-Odobola area of Idah Sheet 267NW, North-Central Nigeria
(6th International Faculty of Science Conference Book of Abstract, Federal University Oye-Ekiti, Ekiti State, Nigeria, 2023) Omanayin, Y. A.; Waziri, N. M.; Onoduku, U. S.; Alabi, A. A.
Pegmatites in the world over have been acknowledged to serve as host to lots of minerals (industrial, ore and gemstones). Recently, there is an upsurge in the interest for pegmatite deposits due to the newly discovered important uses of lithium ores among others. The granitic pegmatite of Ogodo-Odobola in Ajaokuta, Central Nigeria belongs to the pegmatite belt of North-Central Nigeria that has received very little attention and consequently, yet to be well studied. Therefore, detailed geological field mapping of the pegmatites and host rocks aimed at understanding their mode of occurrence and field relationship and to assess their mineralization potentials was conducted. The methods employed for this study include both geological fieldwork and laboratory analysis. Twelve (12) representative samples were selected for petrographic analysis. Geological fieldwork shows the study area is underlain by migmatite gneiss, schist, with intrusions of granite and pegmatite. The pegmatites occur in tabular form with varying widths and lengths. Principal joint directions show NNE-SSW direction which is believed to have influenced the pegmatite emplacement. Petrography of the representative rock samples reveal an average mineralogical composition of hornblende, biotite, quartz, plagioclase, microcline, muscovite, myrmekite and opaque minerals for the host rocks. While microcline, plagioclase, muscovite, biotite, and accessory and opaque mineral for the pegmatites. The pegmatite of the study area is worth probing as the results have shown prospect for possible economic minerals. Keywords: Mineralization, Lithium Ores, Structural Features, Petrography, Ajaokuta