MSC Project (Nancy School of Geology – ENSG)
Prof. Mary Ford, ENSG and CRPG Nancy
This work documents halokinesis within the Toulon Fault Zone (TFZ) in Eastern Provence, at the easternmost termination of the Pyreanean-Provencal orogenic system. A new salt-related structural model of the TFZ is proposed and integrates the inversion of the TFZ at the transition between Apto-Albian rifting and Pyreanean-Provencal convergence.
The E-W Toulon Belt in eastern Provence records Aptian-Albian oblique rifting to Late Cretaceous Pyrenean-Provençal shortening. Relics of the easternmost Apto-Albian Pyrenean rift system are preserved as narrow inverted basins along the northern margin of the Toulon Belt. We present an updated structural interpretation of the eastern Toulon Belt with emphasis on the Mont Caume area, where we document continuous deformation due to salt tectonics from Jurassic to Late-Cretaceous. We then reexamine the better-known western Toulon fault zone and discuss the regional significance of the Toulon fault zone for Cretaceous to Cenozoic paleogeographic reconstructions.
Our field observations are integrated in a salt-tectonic model where the role of the salt deformation is predominant and continuous from early-Jurassic to Santonian times. Mini-basins and halokinetic sequences are observed in the eastern Toulon Belt (Mont Caume, Cap Gros, Mont Faron) surrounded by salt diapirs or salt welds.
This model also integrates the Aptian-Albian pyrenean fault zone and the timing of its structural inversion. Stratigraphic signals in the Mont Caume area may indicate onset of Pyrenean orogenic convergence in Eastern Provence in the Early-Middle Coniacian transition. Paleogeographic reconstruction show that the Turonian to Coniacian clastic sediments that infill the Mont Caume mini-basin came from an emerged massif in the east of Toulon area and that westward sediment routing was constrained by salt wall growth.