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Factor Analysis of Stream Sediment Geochemical Data from Onyami Drainage System, Southwestern Nigeria

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International Journal of Geosciences 2013年第3期4卷 656-661页

作者： Ovie Odokuma-Alonge john Adeyinka adekoya Department of Applied Geology The Federal University of Technology Akure Nigeria Department of Geology University of Benin Benin City Nigeria

An R-mode quartimax rotated factor matrix was applied to a statistical study of stream sediment geochemical data from Onyami drainage system within Igarra area in southwestern Nigeria. The area is underlain by the gneiss-migmatite complex, the low grade supracrustal schist belts and the Pan-African granitoids which intruded both the gneiss-migmatite complex and the supracrustal units. A four-factor model which accounts for 76.49% of the total variance of the stream sediment geochemical data was established. Factor 1 (Sc-Ga-V-La-Ni-Co-Ag-Bi-Sr-Pb-Hf-Nb-Cu-Cr) probably defines an underlying complex granitic lithology with contributions from mafic and ultramafic rocks. Factor 2 (Th-U) is attributable to a granitic lithology which reflects the parent rock as the influencing factor. Factor 3 (Mo-Nb-Zn) appears to define a minor sulphide mineralization associated with granitic rocks that intruded the schists and granite gneiss in the area. Factor 4 indicates the occurrence of gold and its pathfinder element, As, in the study area. This inference is consistent with the reported occurrence and mining of gold during the colonial era in Dagbala, which lies within the Onyami river catchment area.

关键词： Stream Sediment Survey Geochemistry Factor Analysis

Possible Bornu Basin Hydrocarbon Habitat—A Review

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International Journal of Geosciences 2014年第9期5卷 983-996页

作者： john Adeyinka adekoya Peter Sunday Ola Solomon Ojo Olabode Department of Applied Geology Federal University of Technology Akure Nigeria Department of Geological Sciences Osun State University Osogbo Nigeria

An attempt is made in this article to examine and assess the possible petroleum habitat in the Bornu Basin, which is the Nigerian portion of the Mega-Chad Basin that has been found to host oil and gas in commercial quantities in Niger, Chad and Cameroon. The presence of three of the fundamental geological factors (source rock, reservoir rock and seal/trap) for commercial hydrocarbon accumulation was assessed in the light of existing information. Available geochemical information reveals that the shales of the Bima, Gongila and Fika Formations in the Bornu Basin contain sufficient organic matter for hydrocarbon generation. Limited existing geochemical data suggest that the quantity and quality of the organic matter in the shales vary widely with the TOC of most samples ranging from 0.54 wt% - 1.25 wt% and the HI from 11 - 173.80 mg/g in intervals with Tmax in the range of 365°C - 519°C. In addition, the kerogen type is predominantly type III with minor type II, thus suggesting a predominant gas prone basin. Possible reservoir rocks occur as sand/sandstone beds within the Bima, Gombe, and Kerri-Kerri, as well the Gongila Formation which also contains much shale and limestone. Both stratigraphic and structural trapping conditions exist in the Bornu Basin. The structural traps were presumably formed during the widespread Santonian tectonic inversion that affected the entire Mega-Chad Basin. It is suggested that deeper drilling into the sands and sandstone of the untested Bima Formation that could host hydrocarbon of commercial quantities, as evidenced by the discoveries at deeper depths in the neighbouring Termit Basin, was desirable.

关键词： Organic Geochemistry Bornu Basin Source Rock Reservoir Trap

Late Cretaceous/Early Paleocene Biostratigraphy of the Northern Portion of the Bornu Basin, Nigeria

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Open Journal of Geology 2016年第7期6卷 561-570页

作者： Peter S. Ola john A. adekoya Solomon O. Olabode Department of Applied Geology The Federal University of Technology Akure Nigeria Department of Geology Osun State University Oshogbo Nigeria

Ditch cutting samples from Kasade-1 well were processed for microfauna, nannofossil and palynomorphs to throw more light on biostratigraphic events in the northern portion of the Bornu Basin, Nigeria. The lower section of the well within interval 990 - 1565 m yielded fairly abundant foraminifera species, while the upper section was barren. Palynomorph distribution follows the same pattern as observed for foraminifera except that few fresh-water algal species, Botryococcus braunii, were recovered from the upper section. The samples are devoid of nannofossil but contain few ostracod species, echinoid remains and fish tooth. Recognition of two planktonic foraminifera zones, Globotruncanella havanensis and Globotruncana aegyptiaca, enabled the delineation of the Campano-Maastrichtian and Maastrichtian boundary. The Cretaceous Tertiary boundary was inferred based on the top occurrence of palynomorph Dinogymnium euclaense. An abrupt truncation in the distribution of foraminifera species at a depth of about 990 m suggests unconformity, a widely reported event that followed the Santonian squeeze in the entire mega-Chad Basin.

关键词： Microflora Microfauna Cretaceous Unconformity Formation

Geochemistry of Muro Banded Iron-Formation, Central Nigeria

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International Journal of Geosciences 2012年第5期3卷 1074-1083页

作者： john Adeyinka adekoya Chukwuemeka Tony Okonkwo Mohammed O. Adepoju Department of Applied Geology Federal University of Technology Akure Nigeria

Muro Banded Iron-Formation occurs in the Proterozoic Toto Schist Belt, central Nigeria. It consists preponderantly of oxide facies and minor carbonate facies. The oxide facies is made up of alternating bands of quartz (metachert) with those of hematite + magnetite + martite ± goethite, chlorite, pyrrhotite and garnet. The carbonate facies consists of quartz (metachert) + siderite ± goethite. In the oxide facies the total iron content (Fe2O3t) ranges from 33.95% to 48.08% and the SiO2 content from 50.33% to 64.50%. In the case of the carbonate facies, the Fe2O3t content varies from 15.42% to 20.66% and SiO2 content from 66.84 to 72.86%. The Al2O3 content is generally low ranging from 0.1% to 0.54% in the oxide facies, and 0.24% to 0.31% in the carbonate facies. Chemically, the Muro Iron-Formation is similar to the Lake Superior-type iron-formations in terms of the distribution of the major and trace elements. This taken together with similarities in lithological associations indicates its deposition in similar environments i.e. shallow intra-continental or restricted/barred marine basin. The very low Al2O3 contents indicate minor clastic dilution of the original chemical precipitates.

关键词： Muro Iron-Formation Oxide Facies Carbonate Facies Geochemistry Central Nigeria