Tectonics and subsidence evolution of the Sirt Basin, Libya

Abstract

A backstripping analysis of 225 wells located within the Sirt Basin, Libya, provides new constraints on the development of the Sirt Basin. Four tectonic phases are identified from Late Jurassic to present. The presentation of contour maps of subsidence and crustal stretching allows spatial and temporal variations in stretching to be visualized. A close match is observed with stretching phases documented for other African basins, consistent with discrete phases in the opening of the Tethys and Atlantic. Rifting and reactivation appear to be primarily controlled by the orientation of the basin and the underlying basement structure with respect to stress directions. The tectonic subsidence curves have also been forward modeled with an automated modeling technique to quantify the variation in timing and the magnitude of rifting. The tectonic subsidence history of the Sirt Basin is characterized by periods of stretching, alternating with periods of relative tectonic quiescence and thermal subsidence. Stretching started at the centers of the troughs and migrated toward the platform crests.