Abstract
Cenozoic sediments form extensive outcrops in the Niger Delta Basin. Detailed palynostratigraphic study was undertaken across Paleogene sequences exposed in Bende–Umuahia Area in up-dip sectors of the Niger Delta Basin, southeastern Nigeria, to establish different palynomorphs assemblage zones, with their corresponding ages. Palynological analysis was carried out on 27 selected outcrop samples, using the conventional maceration technique for recovering acid-insoluble organic-walled microfossils from sediments. Three Cenozoic lithostratigraphic units, including Imo Formation, Ameki Formation, and Ogwashi Formation, are exposed in the study area. Lithologies are sandstone, carbonaceous shale, mudstone, limestone, and the lignite. A total of 65 species of sporomorphs and 51 dinoflagellate cysts were identified. The recovered spores and pollen grains were used to establish six informal palynomorph assemblage zones, labeled as zone A – zone F, based on the first and the last occurrences of two or more species. These palynomorph assemblage zones include: (1) zone A — middle Paleocene Scabratriporites simpliformis–Bombacidites annae zone; (2) zone B — late Paleocene Foveotricolporites crassiexinus–Mauritidiites crassiexinus zone; (3) zone C — early Eocene Striatopollis catatumbus–Momipites africanus zone; (4) zone D — middle Eocene Margocolporites umuahiaensis–Gemmastephanocolporites brevicolpites zone; (5) zone E — late Eocene Cicatricosisporites dorogensis–Perfotricolpites nigerianus zone; and, (6) zone F — Oligocene–early Miocene Verrucatosporites usmensis–Magnastriatites howardii zone. The erected palynozones were correlated and compared with existing biozones in subsurface, down-dip sectors of the Niger Delta Basin, with pantropical palynological zones in tropical areas of Africa, and with palynofloral provinces of northern South America. A comparison of palynozones studied in southeastern Nigeria with other international palynozones, in this study, will assist in establishing the correlation of sediments for these areas.
Highlights
Cenozoic palynostratigraphic data available for research on the Niger Delta Basin mostly focused on subsurface, down-dip sectors of the basin (Fig. 1)
In the inland part of the Niger Delta Basin, work has focused on the macrofauna and foraminifera biostratigraphy, while little attention was given to palynological biostratigraphy
At the Paleocene–Eocene boundary, in sample L8/05, Proxapertites operculatus reaches its abundance peak (11%); the Paleocene index species assemblage of Scabratriporites simpliformis, Bombacidites annae, Foveotricolporites crassiexinus, and Mauritidiites crassiexinus disappeared and early Eocene markers, Striatopollis catatumbus and Momipites africanus first appeared
Summary
Cenozoic palynostratigraphic data available for research on the Niger Delta Basin mostly focused on subsurface, down-dip sectors of the basin (Fig. 1). Other descriptions of Cenozoic palynostratigraphic data include Evamy et al (1978), Legoux (1978), Sowunmi (1987), Oboh et al (1992), Ojo and Salami (1992), Oboh (1995), Ojo and Adebayo (2001), Ige (2009), Durugbo et al (2010), Lucas and Ishiekwene (2010), Adebayo et al (2012), and, Aturamu et al (2015). The planktonic foraminifer zonation and the calcareous nanofossil biozones of the subsurface Niger Delta have been established by Martini (1971). Notable palynostratigraphic studies include the work of Jan du Chêne et al (1978), who reported some new Eocene pollen from the Ogwashi Formation, and other recent work by Umeji (2002, 2003), Oboh-Ikuenobe et al
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
