Project title: "The effects of salt tectonics in the evolution of a fold and thrust belt", Subalpine Chains, SE France
Supervisors: Dr Lidia Lonergan and Dr Rod Graham
Additional supervisors: Dr Jean-Claude Ringenbach (Total), Professor Jean-Paul Callot (University of Pau), Professor Rob Butler (University of Aberdeen)
In the past decades, our knowledge about salt tectonics has advanced due to improvements in seismic imaging, analogue modelling and hydrocarbon exploration on passive margins around the world including Gulf of Mexico, Santos Basin and Angola. Many of the fold and thrust belts in the Alpine domain (e.g. Betics, Rif, Carpathians and the Alps) comprise evaporitic successions.The structural style and evolution of these orogens has been affected by salt tectonics. These onshore areas, with similar salt-related structures as the passive margins but affected by subsequent compressional deformation have been revisited as an aid to understanding offshore passive margin salt basins
The Southern Subalpine Chains of SE France is one of these mountain belts, and it contains a well-documented succession of Upper Triassic (Keuper) rocks that include gypsiferous evaporite bodies associated with many of the Alpine structures.
The Southern Subalpine Chains formed the passive margin of the Alpine Tethys during its Jurassic-Cretaceous rifting and drifting phase. During the subsequent Alpine shortening the incompetent evaporites and variegated gypsiferous shales have had a significant impact on the development of the fold and thrust belt but the role of the salt-related structures in the preceding passive margin phase is largely unclear.
The salt-related structures and geometries have been modified, and overprinted by the subsequent Alpine deformation. The aim of this project is to investigate the role that salt-tectonics has played during the evolution of the fold and thrust belt and the precursor passive margin in the Southern Subalpine Chains from Triassic to recent times. This mountain belt provides an outstanding natural laboratory for the investigation of the salt-related deformation including those developed before the fold and thrust belt formed.