NEW DEVELOPMENTS IN THE PRE‐RIFT PROSPECTIVITY OF THE ERITREAN RED SEA

Abstract

Northern, central and southern Africa is covered by great thicknesses of Upper Palaeozoic and Mesozoic fluvio‐deltaic and marine siliciclastics, which include important source rocks, reservoirs and seals. In the Eritrean Red Sea, the importance of these rocks has not yet been properly recognised.The Red Sea initially formed by rifting of the Afro‐Arabian continent in Oligo‐Miocene times. Palaeozoic and Mesozoic rocks were downthrown into the resultant Gulf of Suez/ Red Sea Graben and were rapidly buried by syn‐ and post‐rift sediments. In the Eritrean Red Sea area, pre‐rift rocks are now only exposed in the Danakil Alps at the Straits of Bab el Mandab, on the Eritrean Plateau, in the coastal lowlands north of Massawa, and in isolated outcrops in Ethiopia.The authors believe that an as‐yet untested pre‐rift “play” is to be found in the Eritrean Red Sea contiguous with the Danakil Alps. In addition, syn‐ and post‐rift “plays” cannot be ruled out in this area. The combination of newly‐mappedpre‐salt structures, containing Jurassic source rocks and Jurassic and Cretaceous reservoir sandstones and carbonates overlain by Tertiary elastics and/or salt, embodies the primary hydrocarbon entrapment model in the area. Secondary hydrocarbon “plays” centre on deformed Miocene siliciclastic seauences in proximity to salt diapirs.