Chemical and geotechnical assessment of low organic ...
According to Obaje (2009) the Late Cretaceous marine shales correlated with the Nkporo Shale Formation, while the marine beds nearer the coast and offshore are older. The Paleocene Ewekoro Limestone Formation and the Eocene phosphatic Oshosun Formation, which are Lower Tertiary marine units have been exposed at various quarries in Ogun State, and in neighboring Benin Republic.