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Papers by samuel akande
European Scientific Journal, ESJ, 2018
This paper focuses on investigating the paleoenvironments and hydrocarbon generation potentials o... more This paper focuses on investigating the paleoenvironments and hydrocarbon generation potentials of the outcropping Eocene Bende-Ameki Formation at Ogbunike quarry, Anambra Basin southeastern Nigeria, which is the Niger Delta Agbada Formation subsurface equivalent. The fine to coarse sandstones interbedded with parallel laminated grey, coaly shales, and bioturbated claystones were the dominant rock facies. The shales contain Ammobaculities, Ammontium, lenticulina, and Reophax benthic foraminifera of brackish to outer shelf environments. The rock sequence and biofacies associations indicate a fluvial, shoreface to delta environments. The marine and continental paleoenvironments are supported by the concentration and association of redox-sensitive trace elements such as vanadium and nickel of oxic to dysoxic paleoconditions. The twenty shales have a range of TOC from 0.39 - 8.81 wt% (mean 2.2 2 wt%), suggesting a good to very good source rocks. The organic richness is highest within th...
Journal of Petroleum Science and Engineering, 2020
Sedimentology, foraminifera paleoecology, geochemical and petroleum system modelling studies were... more Sedimentology, foraminifera paleoecology, geochemical and petroleum system modelling studies were performed on Cretaceous shales from onshore Orimedu-1 and offshore X (at a water depth of 914 m) wells in the Dahomey Basin, southwestern Nigeria to evaluate their maturity, hydrocarbon generation potentials, and regional significance for petroleum prospectivity. Foraminifera biofacies analysis of the studied shales suggests deposition in dominantly marine environments. The average total organic carbon content (TOC, wt%) and hydrogen index (HI, mgHC/gTOC) for Cenomanian, Turonian, and Coniacian shales in Xwell are 1.3, 0.9, 1.3 and 406, 560, 214 respectively. While the Cenomanian and Turonian shales in Orimedu-1 have TOC (wt%) of 1.3 and 1.9, and HI (mgHC/gTOC) of 179 and 357 respectively. Well X source rocks contain predominantly marine-derived Type II kerogen, while Orimedu-1 well contain terrigenous-derived gas prone kerogen. The integration of recently acquired kinetic data from immature source rocks further constrains the prediction of petroleum generation in the study area. 1D basin modelling of X well reveals that the Cenomanian Source Rock (CSR) is the most mature bed in the basin having attained the initial 10 % transformation ratio (TR) at 87 Ma, got to peak TR (~50 %) at 86 Ma, and reached 83 % at 53.6 Ma. with a present-day thermal maturity of 0.95 % VRo. The Turonian source in well X also attained the initial 10 % TR at 87 Ma, got to peak (~50 % TR) at 86 Ma and 69 % TR at 50 Ma. These modelled source beds are deeper than the source with 0.62 %VRo used for kinetic study. The observed maturity trend is mostly controlled by the regional erosive events associated with the West African rift system during Santonian and Eocene times. The source rocks in Orimedu-1 are immature. The timing of the generated and expelled hydrocarbons into the Cretaceous petroleum systems of Dahomey Basin is of regional significance with the entire Gulf of Guinea basins because of the similar evolution and sedimentation history along with recent discoveries and production of hydrocarbon.
The Upper Cretaceous (Maastrichtian) Araromi Shale formation in the Nigeria sector of the Dahomey... more The Upper Cretaceous (Maastrichtian) Araromi Shale formation in the Nigeria sector of the Dahomey basin has been investigated for its petroleum generation potential. From three exploratory wells, Araromi, Bode Ashe and Gbekebo in the eastern end (west of Niger Delta), source rock potential has been evaluated for over one hundred (100) drill core and ditch cutting samples. The investigated shallow marine shale facies have Total Organic Carbon (TOC) value range of 0.50-4.78wt% and Hydrogen Index (HI) value range of 1-327mgHC/gTOC with the maceral composition of liptinite (av. 26.0%) and abundance of vitrinite (av. 38.1%) plus inertinite (av. 35.9%) in all the samples investigated. Vitrinite reflectance values vary from 0.51-0.68%R<sub>o</sub>. The T<sub>max</sub> values vary from 398<sup>o</sup>C-437<sup>o</sup>C and the kerogen Types include type II, II/III, III, and IV in all the samples. The Source Potential (SP) values range from 0.0...
Journal of Production, Operations Management and Economics
The coastal region of Ondo State, South-western Nigeria is located within the geographical coordi... more The coastal region of Ondo State, South-western Nigeria is located within the geographical coordinates of Latitude 6 21’0” North and Longitude 4 46’o” East. It is the longest coastal line in Nigeria and blessed with marine resources waiting to be exploited. The Blue Economy (BE) is an economic model proposed by Gunter Pauli that lay emphasis on economic activities that depends on the sea and associated sectors, including fishing, transportation, tourism, maritime and energy. Blue Economy growth supports the sustainable growth of the maritime and marine sectors as the oceans and seas are engines of the global economy and have great potential for growth and development of the coastal areas in particular and the nation at large. Apart from oil that are found in the area, other minerals associated with marine are also found in the coastal area under study and the natural environment of the area is particularly suitable for tourism and hospitality. The natural occupation of the people in...
The African Neogene – Climate, Environments and People
Mineralium Deposita, 1989
... Our study of fluid inclusions and stable isotopes of the lower and middle Benue ... The fluid... more ... Our study of fluid inclusions and stable isotopes of the lower and middle Benue ... The fluid inclusion data show that the mineralizing fluids were saline brines containing recognizable hydrocarbons and ... of limestone hosts to veins show that an isotopic halo and fluid evolution on a ...
Global Journal of Geological Sciences, 2012
The Bida Basin is located in central Nigeria and it is perpendicular to the main axis of the Benu... more The Bida Basin is located in central Nigeria and it is perpendicular to the main axis of the Benue Trough. Due to its large areal extent and facies variation, the basin is often geographically divided into northern and southern Bida Basins. Whereas, aspects of the mineral resource and sedimentation history of the sediments in NW and SE extremes have been consistently studied, the present study area (Share-Lafiagi-Shonga areas) remains either unknown or under-reported. In the study area, fifteen vertical profiles of the Campanian-Maastrichtian sediments were studied along road cuts, erosional channels and Cliff sides with special attention focused on their internal physical and biogenic attributes. The sedimentological analysis permitted recognition of five distinct depositional facies; alluvial fan, braided channel, floodplain, tidal channel and shoreface in the lithostratigraphic units mapped. In Unit I, the proximal alluvial fan facies were preserved as conglomeratic facies which ...
Economic Geology, 1987
The Gays River Zn-Pb deposit is hosted in a Carboniferous carbonate bank on the sou ,thern margin... more The Gays River Zn-Pb deposit is hosted in a Carboniferous carbonate bank on the sou ,thern marginal platform of the major (>8 km deep) Fundy-Magdalen basin. Fluid inclusion homogenization temperatures (130 ø-215 ø C) and structural control of the mineralization (determined in our previous study of the immediate mine area) suggest affinities with both MissisSippi Valley-type and Irish-type deposits. New isotopic work, extending to within a 2-km radius of the mine area, significantly constrains genetic hypotheses for the deposit. Preliminary hydrogen isotope measurements of inclusion fluids, together with calculated oxygen isotope compositions, suggest that the mineralizing fluids were basinal brines (/iD =-39%0;/ilSo = +3.3%0). Strontium isotope composition of ore-stage calcite (S7Sr/S6Sr = 0.7117) indicates that components of the strontium and calcium had a source considerably more radiogenic than Mississippian carbonate or evaporite (87Sr/S6Sr = 0.7085-0.7090). These and limited lead isotope data suggest that the fluids had a strontium and metal source in Cambro-Ordovician basement rocks or their immediate elastic derivatives. Sulfur, probably derived from the voluminous Mississippian evaporites (•34S: 14 + 1%o) was probably carried as sulfate (in a fluid with neutral pH) to the depositional site where complete (nonbiogenic?) reduction (at-•200øC) occurred. This is supported by the lack of extensive dissolution and brecciation and the close similarity of the/ia4Szs value for the mineralizing fluids and the/ia4S value of the evaporites. The carbon budget of the ore-forming fluids was dominated by oxidized carbon from a carbonate source with a/i•aC value near 2 per mil, locally influenced by organic carbon with low/i•3C values which is abundant in the Gays River carbonate bank. A basinal brine expulsion model is favored. The hot mineralizing fluid must have originated at a >4-km depth and interacted with elastic, carbonate, and evaporite sedimentary rocks on its way to the depositional site. The likely age for this mineralizing event is approximately 300 m.y. Truesdell, A. H., 1971, Nonideality of oxygen isotope fugacity in salt solutions at elevated temperatures labs. I: Geol. Soc. America Abstracts with Programs, v. 3, p. 735. 1974, Oxygen isotope activities and concentrations in aqueous solutions at elevated temperatures: Consequences for isotope geochemistry: Earth Planet. Sci. Letters, v. 23, p. 387-396.
Journal of Petroleum Exploration and Production Technology
The Patti Formation which consists of sandstone and shale offers the best potential source beds i... more The Patti Formation which consists of sandstone and shale offers the best potential source beds in the Bida Basin. This inland basin is one of the basins currently being tested for hydrocarbon prospectivity in Nigeria. Fresh samples of shale from Agbaja borehole, Ahoko quarry and Geheku road cut were analysed using organic geochemical and palynological techniques to unravel their age, paleoecology, palynofacies and source bed hydrocarbon potential. Palynological data suggest Maastrichtian age for the sediments based on the abundance of microfloral assemblage; Retidiporites magdalenensis, Echitriporites trianguliformis and Buttinia andreevi. Dinocysts belonging to the Spiniferites, Deflandrea and Dinogymnium genera from some of the analysed intervals are indicative of freshwater swamp and normal sea conditions. Palynological evidence further suggests mangrove paleovegetation and humid climate. Relatively high total organic carbon TOC (0.77–8.95 wt%) was obtained for the shales which ...
Journal of African Earth Sciences
Ruhuna Journal of Science
Vitamins are micronutrients needed in the body for important biologic functions. The current stud... more Vitamins are micronutrients needed in the body for important biologic functions. The current study examined the influence of steeping on vitamin C retention of seven Nigerian vegetable leaves after soaking for 8 h. One kilograme each was purchased and 6 lots of 100 g were sorted out, cleaned and treated as follow; whole leaf 1, whole leaf 2, sliced leaf 1, sliced leaf 2, sliced and salted leaf 1 and sliced and salted leaf 2. Each of the treatments 1 was soaked in 1 litre of distilled water while each of treatments 2 was soaked in 2 litres of distilled water. All treatments were kept for 8 h while monitoring the trend of reduction in vitamin C contents at 2 h intervals. Moisture (%) was determined following AOAC (2002) methods while dry matter content was estimated from moisture by calculating the difference. Ascorbic acid content (mg/100 g) was determined following the method of Ndawula et al. (2004). Result showed that; moisture, dry matter, and ascorbic acid contents of raw leaves ranged from 67.63-86.70%, 13.30-32.37%, and 103.00-1199.23 mg/100g respectively. During soaking, ascorbic acid retained by the seven green vegetables reduced as follows; 73.39-24.26% (Amaranthus viridis), 100.26-19.62% (Gnetum africanum), 129.05-27.72% (Gongronema latifolium), 66.84-7.55% (Ocimum gratissmum), 42.59-4.14% (Piper guinense), 77.38-10.26% (Pterocapus mildbedii) and 120.02-17.97% (Telfaria occidentalis). The study showed that ascorbic acid retention (%) of seven Nigerian green vegetable leaves decreased with increasing soaking duration.
Geological Society, London, Special Publications
The Benue Trough formed in close relation to the opening of the South Atlantic and experienced se... more The Benue Trough formed in close relation to the opening of the South Atlantic and experienced sea-level fluctuations of different magnitudes during the Cenomanian to Coniacian interval. We identify depositional environments from outcrop sections and a drilling as control record. Lines of evidence for the interpretation include facies analyses, foraminiferal assemblage composition (P/B-ratio) and the presence of planktonic deep-water indicators. While the analysis of the well data from the Dahomey Basin indicates a continuous deep-water (bathyal) environment, the succession in the Nkalagu area of the Lower Benue Trough evolved in a different and more complex way. Beginning with latest Cenomanian shoreface to shelf deposits, a long period of subsidence lasted until the middle Turonian when pelagic shales and calcareous turbidites were deposited at upper to middle bathyal depths. These conditions continued during late Turonian and Coniacian times. The general deepening trend of the Lo...
Journal of Petroleum Exploration and Production Technology
The Maastrichtian Gombe Formation is located within one of the inland basins of Nigeria (Gongola ... more The Maastrichtian Gombe Formation is located within one of the inland basins of Nigeria (Gongola Basin). Surface and borehole samples of coal and interbedded shale of this formation were evaluated to determine the organic matter richness, quality, maturity, source and depositional environment through organic geochemical techniques such as total organic carbon (TOC) determination, Rock-Eval pyrolysis, chromatography and organic petrography. The genetic potential and average TOC value of the coals, shales and coaly shales are 38.03 wt%, 3.14 wt% and 12.1 wt%, respectively, indicating moderate-to-good source potential. HIs are less than 200 mgHC/gTOC for all the samples indicating Type III kerogen for most of the samples (gas prone) and plant contributions from terrestrial sources. The source rocks were characterized by high molecular weight n-alkanes which range from C 10-C 41 in the coals and C 9-C 41 in the shales. The n-alkanes distributions in the coals maximize at C 29 indicating terrestrial sourced organic matter, while the shales maximize at C 16 and C 29 indicating mixed sources. Pr/ Ph of the coals and shales ranges from (2.15-3.51) to (0.95-2.37), respectively, suggesting fluvio-deltaic deltaic and coastal swamp depositional environments. The predominance of pristane over phytane suggests humic origin of the organic matter. The sterane/hopane values (< 0.6) indicate incorporation of bacterial inputs commonly associated with terrigenous organic matter in the coals. The CPI is greater than unity, T max is generally < 435 °C and vitrinite reflectance less than 0.55 Ro for most of the samples and suggest the samples are of low maturity status to expel liquid hydrocarbon.
Journal of Scientific Research and Reports
The study evaluated the effect of wood by-product on the storability of fresh breaker tomato. The... more The study evaluated the effect of wood by-product on the storability of fresh breaker tomato. The samples (Kerewa variety) were harvested, cooled by aeration and divided into three lots (B0=control; B1=1: 1, tomato: wood by-product; B2=1: 2, tomato: wood by-product). They were kept in uniformly sized paper carton (170 mm×120 mm×140 mm) on the shelf for 28 days. The organoleptic properties of the stored tomatoes were assessed on 5-point hedonic scale, as well as the physicochemical properties (moisture, pH, acidity, and soluble solids), carotenoids, vitamin C content and mineral analysis. Result showed that; B1 and B2 were significantly (p<0.05) higher than control in colour, appearance and overall acceptability while no significant (p<0.05) difference was observed between B1 and the control in firmness and odour. Weight or moisture loss (%) and decay incidence were higher in control than both B1 and B2. Moisture content (MC) reduced significantly (p<0.05) in sample B2 while...
Journal of African Earth Sciences
Journal of African Earth Sciences (and the Middle East)
Lead-zinc-copper mineralization in the lower Benue Trough of Nigeria occurs as discordant fractur... more Lead-zinc-copper mineralization in the lower Benue Trough of Nigeria occurs as discordant fracture controlled veins within the Lower Cretaceous shales of the Asu River Group. Three stages of events are proposed for the evolution of the veins in this district: (i) In'e-ore fracturing and brecciation of Albian shales accompanied by the precipitation of framboidal and colloform aggregates of pyrite, siderite and quartz; (ii) ore stage formation of sphalerite, galena, copper bearing minerals (e.g. ehalcopyrite, bomite, ehalcosite, wittichenite and digenite) tetrahedrite, bournonite and boulangerite; and (iii) final deposition of octahedral galena, sphalerite, bravoite and marcasite in the hanging wall of the veins. Quartz precipitation appears to be at several stages although alarge amount of quartz accompanied the ore stage sulphide precipitation. A mineralogical zoning from a pyrite-galena-sphaledterich top, to chalcopyrite rich base is shown by the larger veins in the district. Post ore oxidation and lateritic weathering of primary vein constituents led to the supergene enrichments of limonite, cerrusite, smithsonite, malachite and azurite which are sometimes preserved with the primary minerals. These mineralogical associations, compositions of the ore and gangue minerals, and the previously reported temperatures of vein minerals are compatible with those of ore deposits formed from basinal brines. The mineralization is considered to be epigenetic and vein formation appears to have accompanied the Cenomanian tectonic event in the Benue basin.
Aapg Bulletin, Jun 1, 1998
... In exposed Cretaceous deposits on a northwest-southeast section from Enugu to Abakaliki, mean... more ... In exposed Cretaceous deposits on a northwest-southeast section from Enugu to Abakaliki, mean ran-dom vitrinite reflectance (Rom ... Nwachukwu (1985) evaluated the area&#x27;s petroleum prospects using the time-temperature index (TTI) concept of thermal maturation of kerogen ...
European Scientific Journal, ESJ, 2018
This paper focuses on investigating the paleoenvironments and hydrocarbon generation potentials o... more This paper focuses on investigating the paleoenvironments and hydrocarbon generation potentials of the outcropping Eocene Bende-Ameki Formation at Ogbunike quarry, Anambra Basin southeastern Nigeria, which is the Niger Delta Agbada Formation subsurface equivalent. The fine to coarse sandstones interbedded with parallel laminated grey, coaly shales, and bioturbated claystones were the dominant rock facies. The shales contain Ammobaculities, Ammontium, lenticulina, and Reophax benthic foraminifera of brackish to outer shelf environments. The rock sequence and biofacies associations indicate a fluvial, shoreface to delta environments. The marine and continental paleoenvironments are supported by the concentration and association of redox-sensitive trace elements such as vanadium and nickel of oxic to dysoxic paleoconditions. The twenty shales have a range of TOC from 0.39 - 8.81 wt% (mean 2.2 2 wt%), suggesting a good to very good source rocks. The organic richness is highest within th...
Journal of Petroleum Science and Engineering, 2020
Sedimentology, foraminifera paleoecology, geochemical and petroleum system modelling studies were... more Sedimentology, foraminifera paleoecology, geochemical and petroleum system modelling studies were performed on Cretaceous shales from onshore Orimedu-1 and offshore X (at a water depth of 914 m) wells in the Dahomey Basin, southwestern Nigeria to evaluate their maturity, hydrocarbon generation potentials, and regional significance for petroleum prospectivity. Foraminifera biofacies analysis of the studied shales suggests deposition in dominantly marine environments. The average total organic carbon content (TOC, wt%) and hydrogen index (HI, mgHC/gTOC) for Cenomanian, Turonian, and Coniacian shales in Xwell are 1.3, 0.9, 1.3 and 406, 560, 214 respectively. While the Cenomanian and Turonian shales in Orimedu-1 have TOC (wt%) of 1.3 and 1.9, and HI (mgHC/gTOC) of 179 and 357 respectively. Well X source rocks contain predominantly marine-derived Type II kerogen, while Orimedu-1 well contain terrigenous-derived gas prone kerogen. The integration of recently acquired kinetic data from immature source rocks further constrains the prediction of petroleum generation in the study area. 1D basin modelling of X well reveals that the Cenomanian Source Rock (CSR) is the most mature bed in the basin having attained the initial 10 % transformation ratio (TR) at 87 Ma, got to peak TR (~50 %) at 86 Ma, and reached 83 % at 53.6 Ma. with a present-day thermal maturity of 0.95 % VRo. The Turonian source in well X also attained the initial 10 % TR at 87 Ma, got to peak (~50 % TR) at 86 Ma and 69 % TR at 50 Ma. These modelled source beds are deeper than the source with 0.62 %VRo used for kinetic study. The observed maturity trend is mostly controlled by the regional erosive events associated with the West African rift system during Santonian and Eocene times. The source rocks in Orimedu-1 are immature. The timing of the generated and expelled hydrocarbons into the Cretaceous petroleum systems of Dahomey Basin is of regional significance with the entire Gulf of Guinea basins because of the similar evolution and sedimentation history along with recent discoveries and production of hydrocarbon.
The Upper Cretaceous (Maastrichtian) Araromi Shale formation in the Nigeria sector of the Dahomey... more The Upper Cretaceous (Maastrichtian) Araromi Shale formation in the Nigeria sector of the Dahomey basin has been investigated for its petroleum generation potential. From three exploratory wells, Araromi, Bode Ashe and Gbekebo in the eastern end (west of Niger Delta), source rock potential has been evaluated for over one hundred (100) drill core and ditch cutting samples. The investigated shallow marine shale facies have Total Organic Carbon (TOC) value range of 0.50-4.78wt% and Hydrogen Index (HI) value range of 1-327mgHC/gTOC with the maceral composition of liptinite (av. 26.0%) and abundance of vitrinite (av. 38.1%) plus inertinite (av. 35.9%) in all the samples investigated. Vitrinite reflectance values vary from 0.51-0.68%R<sub>o</sub>. The T<sub>max</sub> values vary from 398<sup>o</sup>C-437<sup>o</sup>C and the kerogen Types include type II, II/III, III, and IV in all the samples. The Source Potential (SP) values range from 0.0...
Journal of Production, Operations Management and Economics
The coastal region of Ondo State, South-western Nigeria is located within the geographical coordi... more The coastal region of Ondo State, South-western Nigeria is located within the geographical coordinates of Latitude 6 21’0” North and Longitude 4 46’o” East. It is the longest coastal line in Nigeria and blessed with marine resources waiting to be exploited. The Blue Economy (BE) is an economic model proposed by Gunter Pauli that lay emphasis on economic activities that depends on the sea and associated sectors, including fishing, transportation, tourism, maritime and energy. Blue Economy growth supports the sustainable growth of the maritime and marine sectors as the oceans and seas are engines of the global economy and have great potential for growth and development of the coastal areas in particular and the nation at large. Apart from oil that are found in the area, other minerals associated with marine are also found in the coastal area under study and the natural environment of the area is particularly suitable for tourism and hospitality. The natural occupation of the people in...
The African Neogene – Climate, Environments and People
Mineralium Deposita, 1989
... Our study of fluid inclusions and stable isotopes of the lower and middle Benue ... The fluid... more ... Our study of fluid inclusions and stable isotopes of the lower and middle Benue ... The fluid inclusion data show that the mineralizing fluids were saline brines containing recognizable hydrocarbons and ... of limestone hosts to veins show that an isotopic halo and fluid evolution on a ...
Global Journal of Geological Sciences, 2012
The Bida Basin is located in central Nigeria and it is perpendicular to the main axis of the Benu... more The Bida Basin is located in central Nigeria and it is perpendicular to the main axis of the Benue Trough. Due to its large areal extent and facies variation, the basin is often geographically divided into northern and southern Bida Basins. Whereas, aspects of the mineral resource and sedimentation history of the sediments in NW and SE extremes have been consistently studied, the present study area (Share-Lafiagi-Shonga areas) remains either unknown or under-reported. In the study area, fifteen vertical profiles of the Campanian-Maastrichtian sediments were studied along road cuts, erosional channels and Cliff sides with special attention focused on their internal physical and biogenic attributes. The sedimentological analysis permitted recognition of five distinct depositional facies; alluvial fan, braided channel, floodplain, tidal channel and shoreface in the lithostratigraphic units mapped. In Unit I, the proximal alluvial fan facies were preserved as conglomeratic facies which ...
Economic Geology, 1987
The Gays River Zn-Pb deposit is hosted in a Carboniferous carbonate bank on the sou ,thern margin... more The Gays River Zn-Pb deposit is hosted in a Carboniferous carbonate bank on the sou ,thern marginal platform of the major (>8 km deep) Fundy-Magdalen basin. Fluid inclusion homogenization temperatures (130 ø-215 ø C) and structural control of the mineralization (determined in our previous study of the immediate mine area) suggest affinities with both MissisSippi Valley-type and Irish-type deposits. New isotopic work, extending to within a 2-km radius of the mine area, significantly constrains genetic hypotheses for the deposit. Preliminary hydrogen isotope measurements of inclusion fluids, together with calculated oxygen isotope compositions, suggest that the mineralizing fluids were basinal brines (/iD =-39%0;/ilSo = +3.3%0). Strontium isotope composition of ore-stage calcite (S7Sr/S6Sr = 0.7117) indicates that components of the strontium and calcium had a source considerably more radiogenic than Mississippian carbonate or evaporite (87Sr/S6Sr = 0.7085-0.7090). These and limited lead isotope data suggest that the fluids had a strontium and metal source in Cambro-Ordovician basement rocks or their immediate elastic derivatives. Sulfur, probably derived from the voluminous Mississippian evaporites (•34S: 14 + 1%o) was probably carried as sulfate (in a fluid with neutral pH) to the depositional site where complete (nonbiogenic?) reduction (at-•200øC) occurred. This is supported by the lack of extensive dissolution and brecciation and the close similarity of the/ia4Szs value for the mineralizing fluids and the/ia4S value of the evaporites. The carbon budget of the ore-forming fluids was dominated by oxidized carbon from a carbonate source with a/i•aC value near 2 per mil, locally influenced by organic carbon with low/i•3C values which is abundant in the Gays River carbonate bank. A basinal brine expulsion model is favored. The hot mineralizing fluid must have originated at a >4-km depth and interacted with elastic, carbonate, and evaporite sedimentary rocks on its way to the depositional site. The likely age for this mineralizing event is approximately 300 m.y. Truesdell, A. H., 1971, Nonideality of oxygen isotope fugacity in salt solutions at elevated temperatures labs. I: Geol. Soc. America Abstracts with Programs, v. 3, p. 735. 1974, Oxygen isotope activities and concentrations in aqueous solutions at elevated temperatures: Consequences for isotope geochemistry: Earth Planet. Sci. Letters, v. 23, p. 387-396.
Journal of Petroleum Exploration and Production Technology
The Patti Formation which consists of sandstone and shale offers the best potential source beds i... more The Patti Formation which consists of sandstone and shale offers the best potential source beds in the Bida Basin. This inland basin is one of the basins currently being tested for hydrocarbon prospectivity in Nigeria. Fresh samples of shale from Agbaja borehole, Ahoko quarry and Geheku road cut were analysed using organic geochemical and palynological techniques to unravel their age, paleoecology, palynofacies and source bed hydrocarbon potential. Palynological data suggest Maastrichtian age for the sediments based on the abundance of microfloral assemblage; Retidiporites magdalenensis, Echitriporites trianguliformis and Buttinia andreevi. Dinocysts belonging to the Spiniferites, Deflandrea and Dinogymnium genera from some of the analysed intervals are indicative of freshwater swamp and normal sea conditions. Palynological evidence further suggests mangrove paleovegetation and humid climate. Relatively high total organic carbon TOC (0.77–8.95 wt%) was obtained for the shales which ...
Journal of African Earth Sciences
Ruhuna Journal of Science
Vitamins are micronutrients needed in the body for important biologic functions. The current stud... more Vitamins are micronutrients needed in the body for important biologic functions. The current study examined the influence of steeping on vitamin C retention of seven Nigerian vegetable leaves after soaking for 8 h. One kilograme each was purchased and 6 lots of 100 g were sorted out, cleaned and treated as follow; whole leaf 1, whole leaf 2, sliced leaf 1, sliced leaf 2, sliced and salted leaf 1 and sliced and salted leaf 2. Each of the treatments 1 was soaked in 1 litre of distilled water while each of treatments 2 was soaked in 2 litres of distilled water. All treatments were kept for 8 h while monitoring the trend of reduction in vitamin C contents at 2 h intervals. Moisture (%) was determined following AOAC (2002) methods while dry matter content was estimated from moisture by calculating the difference. Ascorbic acid content (mg/100 g) was determined following the method of Ndawula et al. (2004). Result showed that; moisture, dry matter, and ascorbic acid contents of raw leaves ranged from 67.63-86.70%, 13.30-32.37%, and 103.00-1199.23 mg/100g respectively. During soaking, ascorbic acid retained by the seven green vegetables reduced as follows; 73.39-24.26% (Amaranthus viridis), 100.26-19.62% (Gnetum africanum), 129.05-27.72% (Gongronema latifolium), 66.84-7.55% (Ocimum gratissmum), 42.59-4.14% (Piper guinense), 77.38-10.26% (Pterocapus mildbedii) and 120.02-17.97% (Telfaria occidentalis). The study showed that ascorbic acid retention (%) of seven Nigerian green vegetable leaves decreased with increasing soaking duration.
Geological Society, London, Special Publications
The Benue Trough formed in close relation to the opening of the South Atlantic and experienced se... more The Benue Trough formed in close relation to the opening of the South Atlantic and experienced sea-level fluctuations of different magnitudes during the Cenomanian to Coniacian interval. We identify depositional environments from outcrop sections and a drilling as control record. Lines of evidence for the interpretation include facies analyses, foraminiferal assemblage composition (P/B-ratio) and the presence of planktonic deep-water indicators. While the analysis of the well data from the Dahomey Basin indicates a continuous deep-water (bathyal) environment, the succession in the Nkalagu area of the Lower Benue Trough evolved in a different and more complex way. Beginning with latest Cenomanian shoreface to shelf deposits, a long period of subsidence lasted until the middle Turonian when pelagic shales and calcareous turbidites were deposited at upper to middle bathyal depths. These conditions continued during late Turonian and Coniacian times. The general deepening trend of the Lo...
Journal of Petroleum Exploration and Production Technology
The Maastrichtian Gombe Formation is located within one of the inland basins of Nigeria (Gongola ... more The Maastrichtian Gombe Formation is located within one of the inland basins of Nigeria (Gongola Basin). Surface and borehole samples of coal and interbedded shale of this formation were evaluated to determine the organic matter richness, quality, maturity, source and depositional environment through organic geochemical techniques such as total organic carbon (TOC) determination, Rock-Eval pyrolysis, chromatography and organic petrography. The genetic potential and average TOC value of the coals, shales and coaly shales are 38.03 wt%, 3.14 wt% and 12.1 wt%, respectively, indicating moderate-to-good source potential. HIs are less than 200 mgHC/gTOC for all the samples indicating Type III kerogen for most of the samples (gas prone) and plant contributions from terrestrial sources. The source rocks were characterized by high molecular weight n-alkanes which range from C 10-C 41 in the coals and C 9-C 41 in the shales. The n-alkanes distributions in the coals maximize at C 29 indicating terrestrial sourced organic matter, while the shales maximize at C 16 and C 29 indicating mixed sources. Pr/ Ph of the coals and shales ranges from (2.15-3.51) to (0.95-2.37), respectively, suggesting fluvio-deltaic deltaic and coastal swamp depositional environments. The predominance of pristane over phytane suggests humic origin of the organic matter. The sterane/hopane values (< 0.6) indicate incorporation of bacterial inputs commonly associated with terrigenous organic matter in the coals. The CPI is greater than unity, T max is generally < 435 °C and vitrinite reflectance less than 0.55 Ro for most of the samples and suggest the samples are of low maturity status to expel liquid hydrocarbon.
Journal of Scientific Research and Reports
The study evaluated the effect of wood by-product on the storability of fresh breaker tomato. The... more The study evaluated the effect of wood by-product on the storability of fresh breaker tomato. The samples (Kerewa variety) were harvested, cooled by aeration and divided into three lots (B0=control; B1=1: 1, tomato: wood by-product; B2=1: 2, tomato: wood by-product). They were kept in uniformly sized paper carton (170 mm×120 mm×140 mm) on the shelf for 28 days. The organoleptic properties of the stored tomatoes were assessed on 5-point hedonic scale, as well as the physicochemical properties (moisture, pH, acidity, and soluble solids), carotenoids, vitamin C content and mineral analysis. Result showed that; B1 and B2 were significantly (p<0.05) higher than control in colour, appearance and overall acceptability while no significant (p<0.05) difference was observed between B1 and the control in firmness and odour. Weight or moisture loss (%) and decay incidence were higher in control than both B1 and B2. Moisture content (MC) reduced significantly (p<0.05) in sample B2 while...
Journal of African Earth Sciences
Journal of African Earth Sciences (and the Middle East)
Lead-zinc-copper mineralization in the lower Benue Trough of Nigeria occurs as discordant fractur... more Lead-zinc-copper mineralization in the lower Benue Trough of Nigeria occurs as discordant fracture controlled veins within the Lower Cretaceous shales of the Asu River Group. Three stages of events are proposed for the evolution of the veins in this district: (i) In'e-ore fracturing and brecciation of Albian shales accompanied by the precipitation of framboidal and colloform aggregates of pyrite, siderite and quartz; (ii) ore stage formation of sphalerite, galena, copper bearing minerals (e.g. ehalcopyrite, bomite, ehalcosite, wittichenite and digenite) tetrahedrite, bournonite and boulangerite; and (iii) final deposition of octahedral galena, sphalerite, bravoite and marcasite in the hanging wall of the veins. Quartz precipitation appears to be at several stages although alarge amount of quartz accompanied the ore stage sulphide precipitation. A mineralogical zoning from a pyrite-galena-sphaledterich top, to chalcopyrite rich base is shown by the larger veins in the district. Post ore oxidation and lateritic weathering of primary vein constituents led to the supergene enrichments of limonite, cerrusite, smithsonite, malachite and azurite which are sometimes preserved with the primary minerals. These mineralogical associations, compositions of the ore and gangue minerals, and the previously reported temperatures of vein minerals are compatible with those of ore deposits formed from basinal brines. The mineralization is considered to be epigenetic and vein formation appears to have accompanied the Cenomanian tectonic event in the Benue basin.
Aapg Bulletin, Jun 1, 1998
... In exposed Cretaceous deposits on a northwest-southeast section from Enugu to Abakaliki, mean... more ... In exposed Cretaceous deposits on a northwest-southeast section from Enugu to Abakaliki, mean ran-dom vitrinite reflectance (Rom ... Nwachukwu (1985) evaluated the area&#x27;s petroleum prospects using the time-temperature index (TTI) concept of thermal maturation of kerogen ...