Geological Behavior (GBR)

Ten types of dispersed organic matter and palynomorphs were identified from outcrop samples of the Nkporo, Mamu and Nsukka formations including spores and fungi (SP), pollen (PO), freshwater algae (FWA), microforaminiferal inner linings (FL), dinoflagellates (DFL), structured phytoclasts (STPH) (wood, cuticles, parenchyma), unstructured phytoclasts (UNPH) (communited and degraded fragments), black debris (BD) and amorphous organic matter (AOM). The identified palynofacies were analyzed using principal component and cluster analysis (PCA). From the scatter plot, three groups are recognized as indicated by loops namely group A (SP and PO) group B (UNPH, STPH and BD), group C (AOM, FL, ACR and FWA). The heatmap dendogram enabled the definition of four main palyno-ecological groups forming the 1″ order cluster namely Cluster 1A comprising (SP and PO). Cluster 1B comprise of (UNPH, STPH, BD). Cluster 1C comprise of (AOM and FWA). Cluster 1D comprise of (FL, DFL and ACR). The palyno-ecological clusters were grouped according to their environmental significance, Subcluster 1A palyno-ecology is comprised of Pollen (PO) and Spores (SP) while subcluster 1C is made up of Amorphous organic matter (AOM) and Fresh water algae (FWA) These two sub clusters implicated the rainforest and savanna palyno-ecologies as the major prevalent ecologies during the time of sediments deposition. The 1B subcluster indicates palynofacies typical of swamp constituted by structured and unstructured phytoclast and black debris (STPH, UNPH and BD) which was pronounced in Mamu Formation. Cluster 1D comprising of Dinoflagellate (DFL), Foram linings (FL) and Acritarch (ACR) indicated marine palyno-ecologies. Dinoflagellates constitutes a major part of the modern oceanic planktonic distribution. The presence of a wide variety of palynomorphs indicated that the environment supported a rich and diverse tropical flora. Furthermore, the pattern represented on the heatmap pointed to an alternation of ecologies from one with a greater marine influence to swamp/forest and Savanna Palyno-ecological Communities. Moreover, the observed progressive decrease in the abundance of spores and fungi, and the steady increase in the abundance of foraminiferal lining, dinocysts and marine indicator palynomorphs (acritarchs and dinoflagellates) up the stratigraphic column from Nkporo to Nsukka Formation points to greater marine influence and a deepening basin with paludal conditions more evident in Mamu Formation.