Evidence of Atlantic Extension in South-East Togo: Case of Fracturing in the Sandstone Relics of Tohoun

Abstract

The sandstone relics of probable Cretaceous age found around Tohoun show an extensional tectonics imprint associated with the Atlantic opening. This imprint consists of normal fault networks well expressed on two sites of outcrop and corresponds to three fracturing episodes materialized by families of conjugated planes striking E-W, NW-SE, and NE-SW. Striated plane data analysis shows three extensional axes successively N-S, NE-SW and NNW-SSE. The reconstructed paleostress tensors can be attributed to pre-to syn-rift phases responsible for the development of primary basin structures in the Gulf of Guinea. This preliminary analysis, concerning only fractures in the basal sequence relics, remains to be extended to the entire Togolese coastal basin to a better definition of the Atlantic dynamic.