Sedimentary facies and stratigraphy of the Campanian-Maastrichtian Taloka Formation, southeastern Iullemmeden Basin, Nigeria

Abstract

The sedimentology of the Campanian – Maastrichtian Taloka Formation of the southeastern Iullemmeden Basin in Northwest Nigeria is poorly understood. There are still major uncertainties regarding its depositional setting. This study presents a detailed facies analysis and sequence stratigraphic interpretation for the Taloka Formation of Rima Group of the southeastern Iullemmeden Basin in Nigeria based on outcrop observations, sedimentary logging and ichnological analyses. Thin sections, representative of delineated facies associations, are included in the data. Twelve lithofacies and four facies associations were delineated. The facies associations are interpreted to represent intertidal flat, lower shoreface, delta-front and tide-influenced channel environments. The facies associations are arranged vertically into a wave- and tide-influenced deltaic facies succession. Paleosols, low-high bioturbation intensity and low ichnodiversity, (e.g., Thalassinoides and Skolithos ichnofossils) were found in the deposits. Furthermore, the stacking patterns of the Taloka Formation (juxtaposed wave- and tide-influenced facies associations overlain by nearshore and restricted marine deposits) reflect an aggradational set of shallowing upward, progradational parasequences, interpreted as lowstand systems tract: deposits formed when supply balanced accommodation, under low relative sea-level rise condition. A mixed-energy delta model is proposed for the Taloka Formation. The Taloka Formation represents an example of a slowly subsiding, highly-moderately embayed coast.