The opening of Sirte basin: Result of slab avalanching?

North Africa's Sirte basin opening is an enigmatic feature in the complex Meso-Cenozoic rearrangement of Mediterranean tectonics. New borehole data inversion constrains its deformation history showing a stretching event starting similar to 70 Ma and terminating in a further abrupt increase at similar to 50 Ma, rapidly fading afterwards. The timing of this event hardly reconciles with the Mesozoic major plates reorganization following the spreading of the Atlantic, and the Neogene Central Mediterranean tectonics, active at different times. Here, we propose that Sirte rifting could have been driven by the pull exerted by the Hellenic subduction. Reconstructions of Hellenic convergence and slab deep subduction, as constrained by plate kinematics and tomography, show that large slab mass accumulates in the upper mantle by late Cretaceous-Paleogene, eventually forcing further sinking in the lower mantle, coeval to the growing strain evolution recorded in Sirte. Furthermore, the similar to 20 m.y. phase of large pull here recorded, the consequent rapid growth over similar to 10 m.y. and following decay are compatible with the dynamics of slab avalanche as revealed by numerical models, showing that the Sirte basin opened in response to the large pull force developed during the mass flush, and transferred from deep slab to surface. (C) 2009 Elsevier B.V. All rights reserved.