IJSRP, Volume 7, Issue 9, September 2017 Edition [ISSN 2250-3153]
Uzoegbu, M.U. , Okon, O. S.
Late Maastrichtian to Danian limestone of Nsukka Formation in Ohafia and its environs were studied to understand the geological processes that affected the rock after its deposition. The Nsukka Formation in the studied area consists of two facies associations; limestone-shale 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. Palynological analyses of some of the samples indicated that the limestone of Nsukka formation 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 major geochemical element in the limestone samples that was analyzed includes CaO, MgO, SiO2, Al2O3, Fe2O3, Na2O, SO3 and LOI. The limestone consists of CaO as the major constituent followed by SiO2 while Al2O3, Fe2O3 and MgO form the minor constituents. Given the values (42.66% – 94.57%) quoted for calcium carbonate equivalence (CCE). The Ohafia – Ozu Abam – Arochukwu limestone has good potentials for use as petrofertilizers in liming processes.