Geological evolution and depositional architecture of the northern Mauritanian passive margin

• Main Author: Tremblay, Sacha
• Published: University of Aberdeen 2005
• Subjects: 551.760966; Sedimentation and deposition
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420132

The aim of this research was to examine the depositional architecture of the Northern Mauritanian passive margin, West Africa, in order to infer the geological evolution from Mesozoic to Recent. The study is based on a seismic stratigraphic analysis of 2D and 3D seismic reflection data (18000 km2), well data, outcrops and published work. The results are summarised on fifteen paleogeographic maps and key points in the sedimentary and tectonic evolution of this study can be made. Important subsidence in the southern area occurred from the Jurassic to the Turonian, which caused the development of a fractured flexure zone. This was the main tectonic activity clearly seen in the study area. During the Early Cretaceous, the entire study area was located in a siliciclastic deep-water slope environment. From the Late Cretaceous to the Paleocene, the northern study area became progressively shallower and a carbonate platform developed, while deltas were supplying sediment to the deep-water slope in the southern study area. The Paleocene Thermal Maximum climatic event caused the demise of the carbonate platform in the northern area. From the Middle Eocene to the Recent, most of the area was in a siliciclatic deepwater slope environment. Rivers and deltas that drained the adjacent craton were supplying sediment to the area, which exhibits a complex architecture of gravity and bottom current deposits. Presently, numerous deep-water tributary channels incise the seabed of the study area. This study represents the first reconstruction of the paleoenvironmental evolution of the Mauritanian passive margin from Mesozoic to Recent.