LITHOFACIES, PALYNOLOGY AND PALEOENVIRONMENTAL STUDY OF EARLY CAMPANIAN TO MID-MAASTRICHTIAN DEPOSITS OF UDI AND ENVIRONS IN THE ANAMBRA BASIN, SOUTH EASTERN NIGERIA

Abstract

Palynological assemblages, lithofacies and facies association were used in the determination of the age and paleoenvironment of the Enugu and Mamu Formations of Udi area of the Anambra Basin, South east Nigeria. Palynological analysis carried out in over twenty samples (20) yielded spores/pollens and marine Dinoflagelates that are of Early Campanian to Maastrichtian for Enugu shale and middle Maastrichtian for Mamu Formation. The main diagnostic species of spores and pollen recovered includes; Laevigatosporites ovatus, Leiotriletes adriennis, Echitriporites trianguliformis, Longapertites marginatus and Cyathidites minor. Among the main diagnostic dinoflagellates are Operculodinium centrocarpum, Areoligera senoniensis, Spiniferites ramosus, Ceratiopsis spp., Paleocystodinium spp., Dinogymniun accuminatum, Spinferites ramosus and Cordosphaeridium inorders. The coarsening upward sequence of the lithofacies in Mamu Formation is an indication of decrease in sea level, and the intercalation of Siltstone/Sandstone and Shale in the lithofacies of Enugu Shale with its high abundance and diversity of Palynomorphs suggest a shallow-marine environment with Tidal influence.