Palynofacies analysis and paleoenvironmental reconstruction of Umuna well, Anambra basin, Southeastern NIGERIA

Palynofacies analysis and paleoenvironmental reconstruction of Umuna well, Anambra basin, Southeastern NIGERIA Eze Victor Onyedikachi1, Ndubuisi Ukpabi2, Victoria Okereke3 1, 2, 3 Geology Department, University of Port Harcourt, Rivers State. Nigeria. edgar2005ng@gmail.com, ezevictoronye@gmail.com, okerevicto@gmail.com ABSTRACT Depositional environment of thirty-one (31) ditch cuttings from Umuna well were determined using particulate organic matter generated from the ditch cuttings. Umuna well is located in Imo State, within the Anambra basin, South-eastern Nigeria. The ditch cuttings ranged in depth from 1010ft at the top to 2890ft at the base and were prepared into palynological slides following the non-acid sodium hexametaphosphate (NaPO3)6 method for deflocculation of samples, and wet sieved through 10μ diameter sieve. The palynological slide generated were analysed and the different particulate organic matter differentiated based on their grain boundary (Sharp, irregular or diffuse), shape (equidimensional or bladed), colour (opaque or translucent). The analysis yielded percentage distributions of the particulate organic matter components which included the phytoclast, amorphous organic matter and palynomorphs. The results were presented in charts and plotted out in a ternary diagram. The percentage distributions of the phytoclast, amorphous organic matter and palynomorphs plotted in seven depositional environments labelled (I, II, III, IVb, V, VI and IX) within marginal marine to shallow marine. The marginal marine depositional environments predominate in the studied section and included, highly proximal shelf (I), marginal dysoxic-anoxic basin (II) and heterolithic oxic shelf (III), while the shallow marine depositional environments included shelf to basin transition (IVb), mud-dominated oxic shelf (V), proximal suboxic-anoxic shelf (VI) and proximal suboxic-anoxic basin (IX). Key words: paleoenvironment, particulate organic matter, Palynofacies, phytoclasts, palynomorphs. URL: https://www.ijinn.org/papers-published/ijinn-2019-volume-9-issue-