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Article Dans Une Revue Bulletin de la Société Géologique de France Année : 2015

Structural style and evolution of the Pyrenean-Provence thrust belt, SE France

Lucie Bestani
  • Fonction : Auteur
Juliette Lamarche
Marc Floquet
  • Fonction : Auteur
Jean Philip
  • Fonction : Auteur
Fabrice Hollender
  • Fonction : Auteur

Résumé

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 decollement 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 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 southward basin tilting. This major tilting is attributed to the tectonic inversion and basement thrust stacking of the Cap Sicie-Sainte Baume units. Cross section balancing shows a total horizontal basement shortening of 40 km (similar to 35 %) across the Pyrenean-Provence foreland. The main part of this shortening (similar to 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.

Domaines

Tectonique
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Dates et versions

hal-01882008 , version 1 (26-09-2018)

Identifiants

Citer

Lucie Bestani, Nicolas Espurt, Juliette Lamarche, Marc Floquet, Jean Philip, et al.. Structural style and evolution of the Pyrenean-Provence thrust belt, SE France. Bulletin de la Société Géologique de France, 2015, 186 (4-5), pp.223-241. ⟨10.2113/gssgfbull.186.4-5.223⟩. ⟨hal-01882008⟩
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