A palynology and paleoenvironmental study of a section from the Amansiodo-1 well, Anambra Basin, southeastern Nigeria

Abstract

Palynological analysis was carried out on twenty (20) ditch cutting samples from a section (1284.73– 1496.57 m) of the Amansiodo-1 well, Anambra Basin, southeastern Nigeria with the aim of determining the age, biozone, and depositional environment of the sediments within the depth interval. The laboratory techniques of digesting sediments in hydrochloric and hydrofluoric acids for silicates and carbonates removal were followed to process the samples for the recovery of palynomorphs. Fifty two (52) palynomorph specimens were recovered. An assemblage zone of Echitriporites trianguliformis Zone has been established. The section was dated to the upper Maastrichtian due to the occurrences of age diagnostic marker species such as: Cingulatisporites ornatus, Distaverrusporites simplex, Proteacidites sigalii, Dinogymnium cf auclaense, Echitriporites trianguliformis and Retidiporites magdalensis. Based on the palynomorph marine index and environmental indicator flora, the section was inferred to be deposited in marine to brackish (coastal) environments with little influence of fresh water.