Geology
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Item Environmental Impact of Artisanal Gold Mining around Kataeregi Area, North-Central Nigeria(Nigerian Mining and Geosciences Society, 51st Annual Conference Book of Abstracts, 2015-03) Omanayin, Y. A.; Ogunbajo, M. I.The geology and geochemical studies of water, stream sediments and rocks from Kataeregi artisanal gold mining, North-central Nigeria was carried out with the aim of determining its host rocks, assessing the impact of such activity on the surrounding and evaluating the suitability of the water in the area for probable uses. The field work involves the collection of representative rock, water, and sediment samples along stream, mined and background areas within the location of study. The rock and sediment samples were analyzed for trace element concentrations using X-ray fluorescence spectrometry. Water samples were analyzed for cation, anion and trace elements determinations. The average concentration of these trace elements in rocks and sediments were compared with published average crustal abundances of the elements in upper continental crust and the water compared with Nigerian Standard for Drinking Water Quality (NSDWQ, 2007) and World Health Organization (WHO, 2011) Standards. Geological field mapping show that 60% of the total area is underlain by Migmatite Granite-Gneiss complex while Schist account for 20%. The geochemical analysis of the representative rock samples indicates probable Au-Ag-Hg mineralization with average concentrations of 0.16ppm, 2.53ppm, 0.21ppm respectively. Au is hosted by the Schist rocks found within the central portion of the study area while Ag and Hg occur in both Migmatite Granite-Gneiss complex and the Schist rocks. Geochemistry of the sediment samples revealed the sediments are enriched with elements such as Au (0.23ppm), Ag (2.59ppm), Hg (0.21ppm) and Mo (1.14ppm). Findings from the water analyses and Langguth trilinear diagram revealed the water to be earth-alkaline fresh water with high alkaline content, and mostly sulphate type. The elevated Pb content in water is attributed to the influence from local geology and gold mining activities while the Fe and SO4 could results in input from oxidative weathering of pyrite associated with the gold mineralization in the area. These trace metals like Hg in rocks and sediments, and Pb in water from the study area can get consumed directly or indirectly through food chain. They are potential toxic elements that can render water unfit, causes slow growth rate in plant and respiratory, nervous and reproductive disorder in man. Regulations should be put in place to curtail excessive ground opening during mining, environmentally friendly and scientific usage of mercury in gold processing encouraged, and indiscriminate mined waste disposal discouraged. However, it is advisable to explore and exploit for Ag to compliment Au exploitation in the area. Keywords: Geology, Artisanal gold mining, Sediment Geochemistry, Water Quality, Kataeregi. North-central NigeriaItem 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-collisionalItem Water Quality Assessment around Kataeregi Artisanal Gold Mining Site, North-Central Nigeria(Nigerian Society of Mining Engineers (NSME), Book of Proceedings, 2014) Omanayin, Y. A.; Ogunbajo, M. I.; Amadi, A. N.; Abdulfatai, I. A.; Mamodu, A.Hydrochemical assessment was conducted on streams, mine ponds and hand-dug wells around Kataeregi gold mining site, along Minna- Bida road, North-central Nigeria. This was done in order to evaluate the suitability of water in the area for both domestic and irrigational purposes. Fifteen quality parameters: Temperature, pH, TDS, EC, SO4, NO3, HCO3, Cl, Ca, Mg, Na, K, Cu, Fe, As and Pb were analyzed. The abundance of the major ions was in order of Ca2+ > Na+ > Mg2+ > K+ > Fe2+ for cations and HCO3- > SO42- > Cl- > NO3- > PO43- for anions. The water was observed to be earth-alkaline fresh water, which is an indication of water from shallow aquifer system. The results of the field and laboratory revealed that the concentration of most of the parameters were below the maximum permissible limits for a safe drinking water recommended by World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ) except for iron, sulphate and lead whose concentrations at some locations were slightly higher than their respective acceptable limits. The high content of iron and sulphate could be attributed to the oxidative weathering of pyrite associated with the gold mineralization in the area while high lead content observed in the area was due to the weathering and subsequent dissolution of galena, discarded by the artisanal miners during the exploration for gold.Item Geochemical analysis of Jakura-Obajana Marble, Kogi State, North Central Nigeria: Implication for their Industrial Uses(Minna Journal of Geosciences (MJG), 2017) Mamodu, A.; Ako, T. A.; Unuevho, C. I.; Omanayin, Y. A.; Ile, O. T.Geochemical analysis of the Jakura-Obajana marble deposit in Kogi State, North Central Nigeria was investigated. The paper seeks to put into perspective the diverse uses of marble which hinges on its geochemical characterization. Besides the popular use of marble for cement production, the research tends to elucidate other uses of marble predicted on predefined specifications. This will trigger optimal benefit of the Jakura-Obajana marble deposit. To achieve this, fieldwork was carried out to map the rock units underlying the area. Representative marble samples were randomly collected for laboratory analysis using XRF at the Nigerian Geological Survey Agency, Kaduna. The result of the field work reveals that the Jakura-Obajana marble was found occurred with limestone, quartzite and schist. It was also found that marble are the most dominant rock types in the study area. The colour varies from white to grey and the grain sizes range from fine to medium. The geochemical result reveals that CaO and MgO have the average content of 32.37 wt% and 19.57 wt% respectively. The average content of the oxides is 99.43 wt% and the average loss of ignition (LOI) is 43.01 wt%. The average CaCO3 and MgCO3 content of the Jakura-Obajana marble are 58.33 wt% and 41.08 wt% respectively. The percentages indicate that CaCO3 higher than MgCO3. This implies that, the Jakura marble is calcitic in origin. The total carbonate content in the marble is 99.41 %. This makes it suitable for fertilizer production, cement production, and in the production of useful industrial chemical such as sodium carbonate, bicarbonate and hydroxide. It is concluded that the investigated marble deposits have other potential areas of application in addition to usage for cement production, except for animal feeds production and usage as fluxes in steel production.Item 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.Item Geology and Environmental Impact of Aritsanal Gold Mining around Kataeregi area, North-Central Nigeria(Nigerian Journal of Technological Research (NJTR), 2016) Omanayin, Y. A.; Ogunbajo, M. I.Geology and effect of artisanal gold mining was investigated in Kataeregi and environ, North-central Nigeria with the aim of determining its host rock and assessing the impact of such activity on the surrounding. Geological field mapping show the area comprise of the Migmatite-Gneiss complex, Schist, Granite and Sandstone lithologies. The geochemical analysis of the representative rock samples indicates probable Au, Ag and Hg mineralization (0.16 ppm, 2.53 ppm and 0.21 ppm respectively on the average). Au is hosted by auriferous quartz veins within the Schist rock. Geochemistry of the sediment samples revealed the sediments are enriched with elements such as Au (0.23 ppm), Ag (2.59 ppm), Hg (0.21 ppm) and Mo (1.14 ppm). The water is earth-alkaline fresh water with high alkaline content, and mostly sulphate type. The average concentration of these elements in rocks and sediments were compared with published average crustal abundances of the elements in upper continental crust and the water compared with Nigerian Standard for Drinking Water Quality and World Health Organization Standards. Mining activity has impacted the environment with land degradation, loss of vegetation and erosion of soils. Trace elements like Hg in rocks and sediments, and Pb in water from the study area are potential toxic elements that can render water unfit, causes slow growth rate in plant and reproductive disorder in man.Item FORAMINIFERAL BIOSTRATIGRAPHY AND PALEOENVIRONMENT OF WELL BL-1X, DEEP OFFSHORE, NIGER DELTA BASIN, NIGERIA(Journal of Natural and Applied Sciences, 2022-06) Usman, H. O.; Unuevho, C .I.; Chukwuma-Orji, J. N.; Alkali, Y. B.Foraminiferal biostratigraphic analysis was carried out using one hundred and sixty (160) ditch cutting samples from BL-1X well, deep off-shore Niger Delta basin Nigeria. The interval studied is 7710 – 13020 ft belonging to the Agbada Formation. Lithologically, the section varies from shaly-sand to sandy-shale to shale. Biozonation included four planktonic zones, the proposed planktonic zones are: Globgerinoides extremus - G. humerosa zone – interval zone, Globorotalia acostaensis zone – taxon range zone, Globorotalia foshi peripherronda – Globigerinatella insueta – interval zone, Catapsydrax stainforthi zone – taxon range zone which are correlatable with the zones of previous workers. Samples from the section was dated early to late Miocene based on paleontological evidences. Sediments of well BL-1X were deposited in the lower-upper bathyal environment based on environmentally restricted benthic species.