Tag Archives: marginal marine

Pollen and Spores Recovery in Tunga Buzu Carbonaceous Shale Type Section Member: Significance in Sequence Stratigraphy, Age Dating and Paleoenvironment Deduction of the Early Miocene Gwandu Formation, Sokoto Basin, Northwestern Nigeria (Published)

Feld samples were collected from an outcrop at Tunga Buzu with the intention of comparing field relationship between the claystone member and the underlying carbonaceous shale Type Section for palynological study. The study was carried out in order to determine the geologic age relationship of the facies sequence, sequence stratigraphy and paleoenvironment of deposition of the sediments. Lithological description of the beds follows notation of colour, facies composition, texture, fossil content, structure and post depositional diagenetic effects. Laboratory preparation of palynological slides involved decarbonisation, sample digestion using hydrofluoric acid, sieving with 10µm mesh, bleaching of organic debris with nitric acid, maceral separation with zinc bromide, rinsing of separated maceral with ethanol and final mounting of the organomaceral on the slides for microscopic analysis.The carbonaceous shale is light grey in colour, fissile, carbonaceous, slightly bioturbated and ferruginized. Pollen, spores, dinoflagellates and algae were recovered from samples N1-N4. The samples N1-N3 are claystone samples characterised by relatively low assemblage assemblage of miospores with downhole increase in dinoflagellate cysts. The carbonaceous shale (sample N4) is relatively rich in palynomorphs with corresponding high palynomorph population and diversity compared with the claystone facies. Both the claystone and carbonaceous shale contain marker fossils such as Striamonocolpites sp., Retibrevitricolporites obodoensis, Verrutricolporites sp., Praedapollis sp., Belskipollis elegans and Peregnipollis nigericus; indicative of Early Miocene age. The litho-sequence of claystone and carbonaceous shale indicated alternation of continental and marginal marine deposits characterised by paucity and preponderance of peridinacean dinocysts. This suggests eustatic change in sea level of continental Lowstand Systems Tract (LST) and marginal marine Transgressive Systems Tract (TST) deposits respectively. The Tunga Buzu Carbonaceous Shale Type Section constitutes a member of the Early Miocene Gwandu Formation of the Sokoto Basin, Nigeria.

Citation: Ola-Buraimo, A. O. and Haidara, N. (2022) Pollen and Spores Recovery in Tunga Buzu Carbonaceous Shale Type Section Member: Significance in Sequence Stratigraphy, Age Dating and Paleoenvironment Deduction of the Early Miocene Gwandu Formation, Sokoto Basin, Northwestern Nigeria, British Journal of Earth Sciences Research, Vol.10, No.3, pp.16-25

Keywords: Carbonaceous shale, Dinoflagellate, Eustatic change in sea level, Miospore, Type Section, marginal marine

X- Ray Diffraction Studies of Patti Claystone Member of the Campano-Maastrichtian Patti Formation, Southern Bida Basin, North Central Nigeria (Published)

X-ray diffraction and field studies were carried out on the Patti Clay Member of the Patti Formation in the southern Bida Basin. The studies involved field collection of samples and XRD laboratory analysis of clay samples in order to determine the dominant clay type, subordinate associated minerals, geologic processes and paleoenvironment of deposition. Field study involved standard litho-description by noting textural properties, facies type, fossil presence, structure and diagenetic effect. Laboratory XRD analysis procedure included sample grinding, XRD recording condition, selection and measurement of reference minerals, quantification of clay minerals using XRD processing software, XPert-Highscore Plus to generate results indicating clay mineral type and other minerals peaks.  Lithostratigraphic section is dominated by the alternation of sandstone and claystone layers. The sedimentary structures are planar parallel and cross bedding in nature. The sandstone at Ahoko and along Lokoja-Abuja highway is characterized by liesegang ring and bioturbation structures. XRD results indicated that the Patti Clay Members are dominated by kaolinite with subordinate illite, montmorillonite and zincite in rare cases. The clay members were suggested to be deposited by moderate to low energy of transportation, moderate to low rate of deposition through prograding mechanism in a marginal marine setting. The kaolinite clay was formed by meteoric water reaction with the shallow-seated clay members through leaching of K+, Na+ and silica ions with resultant kaolinite stable at adequate pH that was not acidic.

Oladimeji, R.G. and Ola-Buraimo A.O.(2022)X- Ray Diffraction Studies of Patti Claystone Member of the Campano-Maastrichtian Patti Formation, Southern Bida Basin, North Central Nigeria, British Journal of Earth Sciences Research , Vol.10, No.2, pp.24-38

Keywords: Diagenetic effect, kaolinite, liesegang ring structure, marginal marine, prograding and leaching