Possible carbonate buildups in the Palaeocene sequence at the North-eastern margin of Ajdabia trough

Abstract

Analysis of the seismic section from the eastern margin of Ajdabia Trough has resulted in a detailed study of carbonate buildups in the Palaeocene sequence. The main significant features identified in the seismic stratigraphic analysis are isolated mound features within the sequence in the northern shelf area. However, occasional discrete mounds of more diffuse seismic character have been seen in the extreme north-eastern part of the area, in an SW-NE trending feature. Large mounded structure of more than 200 ms thick and is composed of discontinuous, chaotic reflectors has been identified. Evidence for similar mound characters exists at the north-eastern part of the study area. The isolated mounds are draped and onlapped by later Palaeocene sediments. The observed mounds in the Palaeocene sequence are interpreted as carbonate build-ups, which are usually mound-shaped biogenic deposits that display marginal onlapping reflections, whereas the overlying reflections drape the reefs, and the underlying reflections exhibit pulldown effect. This pattern may indicate growth of carbonate build up during the early Palaeocene time. From an exploration point of view, these features within the Palaeocene sequence probably contain the potential for stratigraphic hydrocarbon plays in the area.