Depositional history of a muddy sabkha complex in the Sokoto Basin of Nigeria,West Africa

Sedimentological and stratigraphical analysis of the Sokoto Basin has resulted in recognition of four lithostratigraphic units. They are Unit A—siltstone and fine-grained sandstone; Unit B—shale and marl; Unit C—limestone and calcareous shale; and Unit D—red sandstone. Unit A represents a wadi plain system composed of desert-alluvial beds; Unit B, a mud-rich sabkha system; and Unit C, an inner-shelf carbonate system. A marine transgression from the northwest began in the Maastrichtian and reached its peak in the Palaeocene. After regression in the late Palaeocene, the area was subjected to erosion, followed by fluvial sedimentation of Unit D. Wadi plain beds and mud-rich sabkha facies of Sokoto Basin are similar to alluvial and coastal mud-flat deposits in the northwestern Gulf of California and ephemeral stream and tidal-flat sediments in Gladstone Embayment, Australia.