Late Eocene to Early Miocene Biostragraphy and Palaeoenvironments in the Beta Field of the Northern-Central Niger Delta, Nigeria

• Main Authors: Ugochukwu, Alex Etukokwu, Minapuye, Isaac Odigi, Geoffrey Chijioke, Soronnadi-Ononiwu
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Scientific Research Journal for Engineering, Technology, and Sciences 2019
• Subjects: Biostratigraphy; Paleoenvironment; Paleoecology; Paleoclimate; On-shore Niger Delta; Planktonic foraminifera
• Online Access: http://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/4531

Lithological, palynomorphs and foramininifera studies have been carried on samples from one (1) oil well in the Northern-Central depobelts of the Niger Delta. Fifty six (56) ditch cutting well samples composited at 30ft interval between 3960ft and 9060ft in MT-well Northern Niger Delta. Twenty-two 22 genera of foraminifera comprising mainly benthonic species were identified. Foraminifera and associated palynomorphs recovered from these sandy and shaly sediments permitted the dating, paleoenvironmental and paleoecological interpretation of the analyzed section. The well penetrated the shale and sandstone formations of the Agbada Formation. The studied section was assigned a Late Eocene to Early Miocene age with boundary between Oligocene and Early Miocene marked at 4470ft based on the occurrence of Cicatricosisporites drogensis while boundary between Late Eocene and Oligocene is marked at 7500ft based on the top occurrence Doualaidites laevigatus observed at that depth. Extremely poor recovery of planktonic foraminifera is evident while benthonic foraminifera, shell fragments and ostracods are well represented from 6090-8100ft with increasing faunal abundance and diversity with depth. The Late Eocene corresponds to the F5700 and P400 zones, characterized by the occurrence of Nonionella magnalingua and Cinctipoperioporites mulleri respectively while the Oligocene and early Miocene corresponds to the P500 and P600 zones of the Niger Delta Cenozoic chronostratigraphic chart [29]. The shell fragments indicate a shelf environment and palaeobathymetry is delineated within 0-30m water depth within the inner neritic delta front environment. The depositional settings were found to be similar to the present day Niger Delta, although palaeocology and paleoclimatic conditions were somewhat differ in Eocene to Miocene times of the Cenozoic Niger Delta.