Palynological and Paleoenviromental Studies of the Mamu Formation, Enugu Area, Anambra Basin, Nigeria.

Palynological analyses were carried out on twenty six (26) samples obtained from exposures of Mamu Formation in the Enugu area and two other reference locations to the south of Enugu (Mamu/Ajali transition exposed at Umulolo and part of the Mamu Formation exposed at Leru). Sixty three (63) species of pollens, twenty three (23) species of spores and some dinoflagellates (16 species) and foraminiferal test linings were recovered. The main maastrichtian diagnostic species of pollen and spores include Buttinia andreevi, Cingulasporites omatus, Echitrisporites triaguliformis, Ephedripites ambonoides, Macrotyloma brevicaule, Retidiporites magdalensis, Syncolporites marginatus, Zonosulcites parvus, Constructipollenites ineffectus and Auriculiidites reticulates. Among the dinoflagellates two are diagnostic. They are Andalusiella mauthei, Lejeunecysta sp. Sedimentary structures observed include symmetrical ripples, widespread burrows by trace fossils such as Ophiomorpha and Skolithos. The recovery of greater than 70% of continental palynomorphs shows that the depositional environment of Mamu Formation is probably continental with minor marine incursions. It is probably a Barrier Island setting with occasional transgressive phases resulting in the observed parallic sequences. [ABSTRACT FROM AUTHOR]