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LITHO-PALYNOFACIES OF UPPER CRETACEOUS SEDIMENTS IN THE AFIKPO SYNCLINE, SOUTHEAST NIGERIA.

. International Journal of Research Publication, 3 (100315201862): 18 (April 2018)
DOI: 100315201862.pdf

Abstract

Lithofacies studies of the upper Cretaceous sediments were carried out so as to understand their diagenetic history and depositional environments. The upper Cretaceous sediments in the studied area consist of two facies associations; shale-limestone and cross bedded sandstone. The limestone-shale facies association consists of the following lithofacies; rippled clayey sandstone, carbonaceous shale, heterolithic sandstone-shale, laminated grey shale, fossiliferous limestone, fine grained sandstone, silty shale, medium grained sandstone and carbonaceous sandstone. The cross bedded sandstone facies association consists of only cross bedded sandstone, which is made up of fine to coarse grained sandstones. Palynological analysis of some of the samples indicated that the sediments of upper Cretaceous is of Late Maastrichtian in age due to the abundance of Spinizoncolpites baculatus and Lonapertites marginatus species, with co-occurrence of typical Late Maastrichtian dinoflagellate cysts assemblage, such as, Dinogymnium acuminatum, Senegalinium sp., Andalusiela sp. and Paleocystodinium sp. The shale-limestone facies association is interpreted as sediments from a lagoon / swamp, mixed tidal flat and shoreface to shallow marine shelf environments. The crossbedded sandstone suggests deposition in a moderate to high energy, upper shoreface shallow marine environment.

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