ORGANIC RICHNESS AND MICROFOSSIL CONTENTS ENCOUNTERED IN X-WELL DAHOMEY BASIN, NIGERIA

Abstract

31 rich shale samples obtained from an exploratory X-Well of the Dahomey Basin were investigated to ascertain the organic richness and the microfossil content. The samples were taken at an interval of 30 m running through a total depth of 930 m. The samples were subjected to Total Organic Carbon (TOC), Soluble Organic Matter (SOM) and Micropaleontolgical analyses and various plots were generated from the data obtained. The Total Organic Carbon Content (TOC) of the samples range from 0.31 to 2.22 wt. % with an average value of 1.44 wt. % while the Soluble Organic Matter (SOM) of the samples range from 5400ppm to 38000ppm with an average value of 24500ppm. The results obtained from the TOC and SOM analyses show that the samples have adequate organic matter richness. Also, the plot of TOC against SOM indicates good organic richness. The foraminifera recovered include Lenticulina costata, Globigerina quadrilobatus, Lenticulina inornata, Neoglogloboquadrina dutertrei, Globigerina quadrilobatus, Globigerinoides ruber, Anomalinoides spp., Bulimina exilis, Cancris auriculus, Cibicidoides ungerianus, Globorotalia obesa, Cassigerinella chipolensis, Heterohelepa pseudoungeriana, Lenticulina curvisepta, Ammonia becarii, Epistominella pacifica, Tuborotalia boweri, Morozovella aequa, Globigerina spp., Acarinina pentacamerata, Hanzawaia concentrica, and cibicides sp. Five biozones were established using characteristic assemblage of stratigraphically important planktonic foraminifera The depositional environment ranges from non-marine at the base through shallow marine to deep marine setting at the top.