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The limestone part of the Ewekoro Formation as exposed at a mining site in Sagamu was subjected to lithostratigraphic and geochemical studies. The study aims at a more detailed lithologic description including major elements determination of the limestone deposit at bed levels to better understand the richness of the rocks in terms of calcium content and its sedimentology. Detailed lithostratigraphy of the outcrop was carried out in the field; samples taken were studied using atomic absorption spectrometer (AAS) and gravity method. The samples were scanned using scanning electron microscope. The exposure consists of five beds of two groups of limestone: packstone (Beds, 2, 4 and 5) and wackstone (Beds 1 and 3). Three layers of motorable hardground separated the beds (one between bed 1 and 2, the second between bed 2 and 3 and the third between the limestone and the overlying shale). The richest bed in terms of CaO2 is Bed 3, which also have the lowest SiO2, reflecting the bed that was deposited in the deepest environment. Directly on top of the limestone is the Akinbo shale which consists of two shale facies – black and grey. Generally the limestones were deposited under varying environment of deposition and have been subjected to some varying environmental condition.
Keywords: Ewekoro Formation, limestone, beds, hardground, Calcium Oxide