No abstract

The Provence Chain incorporated preexisting halokinetic and basement features which have played a key role in the structural evolution of the thrust systems. Field structural data, previously published geological maps and exploration well data have been used to interpret a new ~80 km-long balanced and restored cross section across the eastern Provence fold-thrust Diapiric structures were mainly eroded during and after the Pyrenean-Provence compression then reactivated during Oligocene extension and Miocene to present-day Alpine compression. Cross section balancing shows a total horizontal shortening of 28.5 km related to the Pyrenean-Provence and Alpine compressions. The eastern Provence fold-thrust belt integrates preexisting halokinetic folding which can be misinterpreted as resulting to compression. This suggests that a significant amount of folding in fold-thrust belts can results from an early halokinetic fold system developed during the pre-contractional passive margin evolution.

The Pyrenean-Provence fold-thrust belt is characterized by a geological complexity arising from superimposed tectonic history and the propagation of the deformation through a heterogeneous mechanical substratum inherited from Paleozoic and Mesozoic times. The construction of a regional balanced cross section together with field data show that the thrust system of the southeastern Provence region is characterized by a mixed thick-and thin-skinned tectonic style related to the inversion of deep-seated late Paleozoic-Triassic extensional structures and the décollement of the Mesozoic-Cenozoic sedimentary cover above Triassic series. Earliest Cenomanian restoration state highlights the northward pinched-out of the Lower Cretaceous sedimentary series above the main long-wavelength Durance High uplift. Latest Santonian restoration state indicates a southward tilting of~2 o of the basin attributed to the initial growth of the Pyrenean-Provence prism controlling the external flexure of the foreland. Thrusts propagation in the northern part of the Pyrenean-Provence fold-thrust belt was recorded to be synchronous during latest Cretaceous to Eocene time and produced a~7 o southward basin tilting. This major tilting is attributed to the tectonic inversion and basement thrust stacking of the Cap Sicié-Sainte Baume units. Cross section balancing shows a total horizontal basement shortening of 40 km (~35 %) across the Pyrenean-Provence foreland. The main part of this shortening (~37 km) was accommodated by thick-skinned thrusts involving basement south of the Arc syncline.~5 km of shortening were accommodated northward by the Arc syncline and eastern Sainte-Victoire thin-skin structures, resulting from slip transferred from the deep thick-skinned intercutaneous thrust wedge. Finally we interpret salt tectonic structures of the southeastern Provence as passive diapirism growth during Jurassic to late Cretaceous time, and then reactivated during Pyrenean-Provence compression. Late normal faulting related to hypothetical reactive diapirism during the Oligocene extension episode was predominantly localized above inherited salt structures and probably controlled by inherited basement faults. Style structural et évolution de l'avant-pays pyrénéo-provençal, SE FranceMots-clés. -Architecture structurale, Inversion tectonique, Héritage, Coupes équilibrées, Avant-pays pyrénéo-provençalRésumé. -L'avant-pays pyrénéo-provençal est caractérisé par une structure géologique complexe résultant d'une histoire tectonique polyphasée et de la propagation de la déformation dans un substratum mécanique hétérogène qui est hé-rité du Paléozoïque et du Mésozoïque. La construction d'une coupe équilibrée régionale ainsi que les données de terrain montrent que l'avant-pays provençal, localisé dans le SE de la région de Provence, est caractérisé par un style tectonique mixte de couverture et de socle relié à l'inversion de structures extensives profondes du Paléozoïque supé-rieur-Trias et de décollements de la couverture sédimentaire Mésozoïque-Cénozoïque s...