Journal de géologie et géophysique
Libre accès

Abstrait

Micropaleotological studies of Ewekoro Sediments Southwestern Nigeria

Oladosu YC and Ogundipe OY

The study determines the micropaleontological studies of Ewekoro sediments in South Western region of Nigeria. The area of the study lies between latitudes 6°47N-6°53N and longitudes 335E-3°40E. Samples were collected from fleshly exposed surface of Ewekoro formation of Dahomey basin at an interval of 2 m. These samples were subjected to lithological description to determine the grain size, color, sorting also to standard micropaleontological analysis to recover the foraminifera which were used to determine the age, paleonenvironment of deposition and stratigraphic equivalence of the formation. The study showed that the limestone at the basal part of the sequence were sub-angular to sub-rounded shaped, poorly sorted and with yellowish brown color indicate disturbed environment. While the upper shale are fined grained, greenish in color, dark-grey and showing high fissility. The foraminifera recovered include, Lenticulina degolyeri, globorotalia, pseudomonarrdii, Globigerina linaperta, Globigerina yeguaensis and cibicides sp. This is occurrence of some planktonic foraminifera which are indicative of marine environment. Therefore, there must have been an incursion of marine water into the environment. However, the paleoenvironment of deposition ranged from inner neritic to middle neritic.