Fracture kinematics, cementation and burial history of a structurally polyphase sedimentary basin, Tunisia

• Main Author: Jennings, Jonathan Simon
• Format: Thesis
• Language: unknown
• Published: Kingston University 2001
• Subjects: Earth systems and environmental sciences; North Atlantic
• Online Access: https://eprints.kingston.ac.uk/id/eprint/20680/; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366440

Basin analysis of over 1000km of 2-D seismic profiles and thirteen exploration wells from the North and South Kairouan Permits in the foreland region of the Tunisian Atlas has led to the identification of a number of late Mesozoic to recent basin systems. The generation of these basin systems resulted in the development of fractures and emplacement of diagenetic fluids and hydrocarbons in the early Campanian to early Maastrichtian (83.5-70Ma) chalks of the Abiod Formation. Recognition of the basin-forming events has been based on the identification of regional unconformities, subsurface thickness variations of mid-Cretaceous to recent strata, and changes in the location and size of depocentres. The basin systems correspond to: (1) early Albian to early Campanian (110-83.5Ma) extension related to convergence across Tethys during the opening of the North Atlantic; (2) early Campanian to late Langhian (83.5-l5Ma) basin inversion and salt diapirism related to the convergence between Africa and Europe; (3) late Langhian to late Tortonian (15-7Ma) basin inversion, salt diapirism and foreland basin sedimentation associated with the southeastwards propagation of the Atlas Mountains thrust-system through the Mejerda Zone, Intermediate Atlas and into the North-South Axis; (4) late Tortonian to Late Pliocene (7-1.8Ma) extension related to the opening of the Strait of Sicily and foreland basin sedimentation from the North-South Axis; (5) Late Pliocene to recent (1.8- 0Ma) basin inversion related to the final stages of deformation along the North-South Axis. Hydrocarbons in the North and South Kairouan Permits are produced from open and partially open fractures in the upper Abiod Formation. Petrographic analysis has allowed the identification of ferroan calcite, ferroan dolomite and barite cements in fractures of the upper Abiod Formation which were emplaced in that order. The integration of burial history modelling and fluid inclusion analysis suggests that the pressure-corrected homogenisation temperatures (trapping ...