The onshore Blue Nile Basin, Ethiopia: An analogue for the volcanically-affected Faroe-Shetland Basin.

The Blue Nile Basin, Ethiopia is a suitable and well-exposed analogue for the volcanically-affected Faroe-Shetland Basin, NE Atlantic Ocean. Subaerial volcanism in both basins is characterised by trappean flood basalts that fill the pre-existing topography and are superseded by point-sourced shield volcanoes. The volcanic successions have also been suggested to act as potential seals in petroleum systems that consist of Upper Jurassic source rocks. Unlike the submerged Faroe-Shetland Basin however, the Blue Nile Basin has been uplifted and the subsequent incision by the Blue Nile river has exposed a >1.5 km thick Mesozoic sedimentary succession mantled by the Ethiopian Flood Basalt Province. The characteristic plateau capping the trappean flood basalts is found at a mean elevation of ~2.5 km above sea level and the generally flat-lying terrain provides good access around the basin. Initial investigations have documented, for example, the transition from the underlying fluvial sandstones into the trappean flood basalts, the occurrence and nature of substantial interlava sedimentary sequences, including siliciclastic sandstones, and variations in thickness and facies of volcanic sequences across the basin. An active petroleum system is also shown by the occurrence of bitumen seeps in the flood basalts. Observations from the Blue Nile Basin provide important insights into the evolution of the Faroe-Shetland Basin, where many challenges still remain in the development of and exploration for sub- and intra-volcanic plays.