Paleoclimatic significance of microflora retrieved from Well ‘Y’, Western Niger Delta, Nigeria

Abstract

Palynomorph species comprising 53 pollen, 7 spores, 2 algae and 6 dinoflagellate cysts were recovered from a section of well ‘Y’ located in the offshore western Niger Delta and were used for paleoclimatic deductions of the sediments. There was a dominance of the fresh water swamp species over the brackish, savannah and the rain forest types. Stratigraphically, four floral zones corresponding to inferred climatic units were identified. M2 floral zone, at the lower portion of the well, occurred between 8150 ft (2486 m) and 6440 ft (2147 m). It corresponded to wet and humid climate with periodic rainfall. M1 floral zone was between 6440 ft (1964 m) and4820 ft (1470 m) indicating a dry climatic phase in a high sea level stand. The P7 floral zone was also a humid climate in a sea level rising environment while the topmost floral zone between 4370 ft (1333 m) and3125 ft (953 m) was a fluctuating dry and wet climatic phase in a tidally influenced environment. A humid tropical climate characterised by alternation of dry and wet regimes occasioned by sea level changes and cyclic fluctuation in continental climatic condition is inferred from the analysed well that spanned through Late Miocene and Early Pliocene.

Keywords: Floral zones; Niger Delta; Paleoclimate; Palynomorphs; spores; pollen