Salt tectonics and its effect on the structural and sedimentary evolution of the Jeffara Basin, Southern Tunisia

• Published in: Tectonophysics Vol. 744; pp. 350 - 372
• Main Authors: El Rabia, Aicha, Inoubli, Mohamed Hedi, Ouaja, Mohamed, Abidi, Oussama, Sebei, Kawthar, Jlailia, Ali
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 02.10.2018; Elsevier BV
• Subjects: Arid climates; Aridity; Cenozoic; Diapirism; Diapirs; Drills; Dynamics; Eocene; Evolution; Exploration; Geological data; Gravitation; Gravity; Jeffara Basin; Kinematics; Migration; Modelling; Naval engineering; Ocean models; Oceans; Oil exploration; Organizations; Paleoceanography; Passive margin; Passive margins; Petroleum; Plate tectonics; Rheological properties; Rheology; Rifting; Sabkhas; Salt movement; Salt pillows; Salt walls; Salts; Sedimentary environments; Sedimentation; Sediments; Seismic activity; Seismic profiles; Seismic response; Seismic velocities; Seismology; Synclines; Tectonics; Triassic; Tunisia; Salt walls; Passive margin; Salt movement; Jeffara Basin; Diapirism; Salt pillows
• ISSN: 0040-1951; 1879-3266
• DOI: 10.1016/j.tecto.2018.07.015

The Jeffara Basin, as part of the North African passive margin, provides a specific type of salt-wall diapirism in Tunisia. A comprehensive study, integrating seismic, gravity, drill wells and surface geological data is performed to model the induced salt geometry and delineate its kinematics. Salt bodies, originated from the Triassic Norian series, are characterized by chaotic seismic response, higher seismic velocity and gravity mass deficit. The architecture of the marine Jeffara Basin results from the complex evolution initiated by Tethyan Ocean rifting. The reconstructed palinspastic sections together with analogic halokinetic models show the successive stages of salt movement and the development of peripheral rim synclines and associated minibasins. Arid climate Triassic developed prolific upper intertidal to supratidal coastal sabkhas bordering the Tethyan Ocean enabled the deposition of thick Triassic salt within the marine Jeffara Basin. During the Early Hettangian extensional phase, associated with the opening of the Tethys Ocean, initiated a series of normal faults. Onlap reflection terminations of Late Hettangian horizons indicate the early Triassic salt rising activity. Large depocenters occurred during Santonian to Eocene; their lateral migration indicates the main active period of salt. Salt pierced the entire sedimentary cover, reached advanced salt diapir stage and set up salt walls during the Cenozoic period. Salt movement mechanism is dictated by the combined effect of tectonism and salt rheology. Salt dynamics controlled the sedimentation and the organization of depositional environments of sediments. Structural interpretation and modeling of the available seismic sections are of critical importance to get a better understating of the evolution of salt structures within the study area. Salt pillows are located at the central part of the basin. To the northeastern part, where thick salts accumulate exhibits the most mature and extended salt-walls. These geometries have an important impact on petroleum exploration. [Display omitted] •Depositional environments allow mini-basins occurrence and other related salt structures that impact the petroleum exploration play.•Reactive, active and passive stages are deduced and extensional fracturing Triggered salt movement.•Salt-engine is driven by buoyancy and differential sediment loading. Salt is originated from Triassic evaporites•Jeffara basin shares comparable characteristics to other passive margins in the world