Paleoclimatic Changes and Palynocycles of The Late-Tertiary Niger Delta, Southern Nigeria

Palynological studies in Nigeria in the past four and a half decades were primarily based on the needs of the oil industries and information from them has remained confidential. Most of the studies were largely concerned with systematic descriptions of pollen and spores, palynological zonations, and bio-stratigraphy. Apart from the published works of on the Late Quaternary Eastern Niger Delta. This study therefore, presents vegetational and climatic changes in the Late Tertiary Niger Delta, Nigeria based on pollen record from MIC 2 well. It will serve as a contribution to the knowledge of the Niger Delta environmental changes as reflected by vegetation particularly at Miocene/Pliocene periods where there is a dearth of published information. A Late Miocene Late Pliocene ages belonging to P850, P860, P860, P870, P880 and P920 zones of Evamy et al., (1978) were established for the interval under study. Palynocycles are recurrent palynological sequences reflecting vegetational changes determined by cyclic sea level oscillations and the associated climatic variations. During this study, six climatic cycles were recognised and used to infer the depositional cycles that indicate recurrent palynogical sequences and vegetation changes based on the sea level change. The wet cycle suggests highstand / transgressive systems tracts, while the dry cycle indicates lowstand systems tracts. Palyno-ecological communities encountered in the analysed interval of the well reveals clear crests and troughs in the microfloral abundance indicating fluctuations of dry and wet climates during the deposition of the sediments enabling three major Palynocycles within intervals 4142 – 2650, 2650 – 1450, and 1450 – 450 to be identified.