Paleoecology and Paleodepositional Environment of Ostracod from Igumale Formation, Southern Benue Trough, Nigeria

Publication Date : 23/05/2022


Author(s) :

Ogbahon, O.A, Opeloye, S.A., Oluwajana, O.A.


Volume/Issue :
Volume 58
,
Issue 1
(05 - 2022)



Abstract :

Ostracod fauna from Igumale Formation of the Cenomanian-Turonian Eze Aku Group in the Southern Benue Trough have been studied to document the assemblage, paleoecology and depositional environment of the sediment in the stratigraphic interval. Seventeen core samples spanning a stratigraphic interval of 85.34 m were analyzed for ostracod. The lithologic composition of lithostratigraphic unit consists of siliciclastic-carbonate sequences with the carbonates more conspicuous at the upper portion of the stratigraphic section. A total number of eight species belonging to five genera and five families were recovered from the samples. The recorded ostracod taxa are Bythocypris sp., Bairdia malzi, Bairdia illaroensis, Bairdia sp., Cytherella aegyptopuntata, Cytherella farafraensis, Xestoleberis sp.and Paracosta parakefensis listed in order of decreasing abundance. Of the total population abundance of 138, Bythocypris sp is the dominant taxa, accounts for 69.6 % of the population. Its distribution is however cyclical, suggesting fluctuation in sea level. Based on the low species diversity, environmental preferences of the recorded taxa and distributional pattern, shallow marine depositional environment (inner to middle shelf) is deduced for the fossiliferous portion of the section with dissolved oxygen levels fluctuating between well oxygenated and disaerobia


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