A Pleistocene cyclothem in the Rokel estuary (Sierra Leone, West Africa)

Abstract

Pleistocene sediments overlie the area around the Rokel estuary of Sierra Leone. These are part of a series of Tertiary and Quaternary sediments forming the Bullom Group. Borehole samples of the Pleistocene sediments reveal a sequence of interbedded sands and clays with horizons of lignite. Repetition of the sequence is observed and has led to the establishment of a cyclothem. It is concluded that the cyclothem results from sea-level changes in the area during the Pleistocene.