Saka Opeloye | Federal University Of Technology Akure,Nigeria (original) (raw)

Papers by Saka Opeloye

Modeling Earth Systems and Environment

Global Journal of Geological Sciences, 2016

Journal of Applied Sciences, 2005

Arabian Journal of Geosciences

Global Journal of Geological Sciences, 2016

Biostratigraphic and paleoecological studies of foraminifera in the Opolo-5 well within depth sli... more Biostratigraphic and paleoecological studies of foraminifera in the Opolo-5 well within depth slice 3125ft and 8150ft (953m and 2484m) was conducted to establish both bio/ecozones of the sediments penetrated by the well. Two planktonic and four informal benthonic zones are established. They are Globoquadrina dehiscens and Globigerinoides ruber Planktonic zones as well as Cyclamina cancellata, Lenticulina inornata, Marginulina costata/ Quinqueloculina microcostata and Heterolepa pseudogeriana informal zones. They range between Late Miocene to Early Pliocene. Wall structure discrimination ternary plots indicate the influence of salinity in the foraminiferal distribution. Normal marine to hypersaline environment is inferred for the upper horizons of the investigated section between depth slice 5030-3170ft (1533-966m), brackish to normal marine for depth slice 6230-5030ft (1899-1533m) while the deeper horizon beyond 6230ft (1899m) are brackish. The various morphological forms indicate i...

The Aptian-Albian Bima Sandstone rests discomformably on the Precambrian crystalline basement in ... more The Aptian-Albian Bima Sandstone rests discomformably on the Precambrian crystalline basement in the northeastern basins of Nigeria. The formation which is widely exposed in the Upper Benue portion of the basins was investigated for lithofacies associations with a view to deducing the nature of the depositional environment. The facies geometry reflects a pullapart origin as the facies distribution represents a basinward change in depositional environments from marginal alluvial fan to axial lacustrine system. The alluvial architecture and stacking patterns depict sedimentations mainly controlled by allogenic factors of climate and tectonism. Ten lithofacies, identified on the basis of lithology, grain size, and sedimentary structure, constitute four main lithofacies associations (FA I to FA IV) representing distinctive depositional environments. FA I is a conglomeratic facies association representing gravity driven talus and debris flow fan deposits. FA II is a major tabular sandsto...

The paleoenvironment of the Numanha Shale was analysed from the study of limestones as well as th... more The paleoenvironment of the Numanha Shale was analysed from the study of limestones as well as the microfossil content of the shale units. The cyclicity of the interbedded lithounits is attributed to depth fluctuation. The limestone beds are intramicrite and biosparmicrite while the microfossils indicate a shallow marine, brackish-water environment. The foraminiferal assemblage is dominated by species of Ammobaculites, Haplophragmoides and Heterohelix while the ostracods are composed of the smooth cyprideids and cytherideids of shoreline habitat with Ovocytheridea in abundance. The age of the Numanha Shale is deduced as Turonian-Coniacian based on the occurrences of Heterohelix species.

Journal of Emerging Trends in Engineering and Applied Sciences, 2013

Textural characteristics and petrographic assessments of siliciclasts are assessed for the purpos... more Textural characteristics and petrographic assessments of siliciclasts are assessed for the purpose of establishing mechanism of sediment deposition and the rock bulk properties of the Ajali Formation in the western flank of Anambra basin in Nigeria. Outcrops of the formation are well exposed along the long reach of Orle stream in Auchi as well as road embarkments at Ayogwiri, Fugar and Othame environs in the western flank of the Anambra Basin, southwestern Nigeria. Modal composition of the siliciclasts is Q90.5-96 F0-3.1 and L1-8.4 which classified it as Quartzarenite sandstone. The sandstone is texturally homogenous as its sediments are generally medium grained, moderately sorted and non-platykurtic, indicating tidally influenced deposition. The dominant quartz minerals occurred mainly in non-undulatory, strain-free monocrystalline forms indicating bulk derivation from the basement cratonic interior. Its authigenic growth as silica precipitation from pressure solution was most evid...

This study focusses on the sedimentological and aeromagnetic characteristics within the Agbaja Ir... more This study focusses on the sedimentological and aeromagnetic characteristics within the Agbaja Ironstone Formation to establish the sedimentary depositional history and map oolitic ironstone zones in the Lokoja district of the Nupe Basin. Forty sandstone samples were collected for granulometric, sedimentary facies and petrographic analyses to reconstruct depositional processes of the Agbaja Ironstone Formation. Aeromagnetic data analysis was engaged to map the oolitic ironstone rich zones. The iron-rich sandstones in the Agbaja Ironstone Formation occur as oolitic ironstone, ironstone concretion and laterites. The bivariate grain size plots and multivariate discriminant analyses suggest that 92% of the sandstone in the formation were deposited in beach and coastal dunes under fluvial-river actions, while 8% are of the marine environment deposited under wave actions. The quartz-feldspar lithic (QFL) ternary diagram and palaeocurrent analyses of the samples revealed that the matured, ...