Source-Rock Potential and Paleoenvironment of the Coniacian Numanha Formation, Northeastern Nigeria: An Integrated Palynofacies and Geochemical Approach
A study of source-rock characterization and paleoenvironmental interpretation has been carried out on a relatively thick Coniacian sedimentary succession from the Numanha Formation in the Guyuk area of the Yola arm in the Northern Benue Trough, northeastern Nigeria. The aim is to provide organic facies data for the assessment of its hydrocarbon generating potential owing to the high prospects of its lateral equivalent Fika Shale in the Gongola arm of the Northern Benue Trough. The investigation of 98 samples from three outcrop sections [09° 50′ N, 11° 51′ E; 09° 54′ N, 11° 50′ E; 09° 54′ N, 11° 49′ E] which includes palynofacies analysis, spore/pollen coloration, and geochemical analyses enabled an evaluation of organic matter richness and quality. Measured TOC ranges between 0.01 and 7.4% which reflects poor to good organic richness, while visual kerogen characterization shows thermally mature Type II-III kerogen indicative of oil and gas prone materials. Recovered palynomorphs comprised both marine (dinoflagellate cysts, microforaminiferal test linings) and terrestrial (spores, pollen, freshwater alga Pediastrum) taxa. These palynomorphs vary in proportion at different horizons of the sections indicating shoreline fluctuations. Except for the Kurnyi section, amorphous organic matter occurs in minor percentages, indicating low preservation potential during deposition. All data indicate that the Numanha Formation was deposited in a highly proximal to mud-dominated oxic shelf environment.
Y. B. Valdon et al., "Source-Rock Potential and Paleoenvironment of the Coniacian Numanha Formation, Northeastern Nigeria: An Integrated Palynofacies and Geochemical Approach," Journal of African Earth Sciences, vol. 198, article no. 104790, Elsevier, Feb 2023.
The definitive version is available at https://doi.org/10.1016/j.jafrearsci.2022.104790
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Cretaceous; Numanha Formation; Paleoenvironment; Palynofacies; Yola Arm
International Standard Serial Number (ISSN)
Article - Journal
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01 Feb 2023