Deep Structure And Crustal Configuration Of The Jeffara Basin (southern Tunisia) Based On Regional Gravity, Seismic Reflection And Borehole Data: How To Explain A Gravity Maximum Within A Large Sedimentary Basin?

摘要

The Jeffara basin of southern Tunisia contains a thick sequence of mainly Triassic and Permian sediments that is characterized by a gravity maximum. To explain the positive gravity signature over the Jeffara sedimentary basin and to obtain a more quantitative representation of the subsurface structure, a regional 2.5D gravity model constrained by seismic reflection and borehole data was constructed along a NE-SW trending profile. The depth to the crust/mantle implies that the Jeffara basin is associated with crustal thinning. The gravity model also implies that subsidence is controlled by a basement stepped down by relatively low-displacement faulting. This sedimentary subsidence, as described by a listric-faulting model, is probably caused by a thinned crust.