The Geologic History of the Marginal Basins Along the North Shore of the Gulf of Guinea

Abstract

The North shore of the Gulf of Guinea forms the coastline of Liberia, the Ivory Coast, Ghana, Togo, Dahomey, Nigeria, and the Cameroons (Fig. 1). The westernmost point of the coastal region to be discussed here is Cape Palmas (long 8° W) on the border between Liberia and the Ivory Coast. The easternmost limit is formed by the Cameroons Bight at long 9° 30′ E. The marginal basins are limited to the north by the upper Guinea arch which stretches for more than 2000 km in a west-east direction from Liberia to the Cameroons. In this arch region the metamorphic basement is exposed over wide areas. Some of the details of this basement are discussed by Hurley and Rand, and by Grant in this book. For the purposes of the Atlantic marginal basins discussed here, it is sufficient to state that in the region of the Ivory Coast and Ghana the basement (Birrimian shield) was consolidated towards the end of the middle Precambrian (Bonhomme, 1962); in Dahomey and in Nigeria, on the other hand, it was only consolidated in the youngest Precambrian (Black, 1967).