The role of syn-rift saliferous tectonics during the opening of the Pyrenean rift

An article in Basin Research with Thibault Duretz, Riccardo Asti and Yves Lagabrielle

Th. Duretz et Al. 2019 Basin Research
The formation of the Pyrenees belt was preceded by an episode of rifting during the Lower Cretaceous (~140 to ~100 Ma). These basins were opened in a heterogeneous lithosphere inherited from the hercynian orogenesis and a complex mesozoic evolution, which included deposition of thick deposits of Triassic salts and evaporites (Keuper). These deposits locally underwent high temperature metamorphism during the Cretaceous rifting, which is a specific feature of the Pyrenean case.
T. Duretz et al. Basin Research 2019 - © Thibault duretz

Using thermo-mechanical digital models, researchers from Géosciences Rennes - Thibault Duretz, Riccardo Asti, Yves Lagabrielle, Jean Pierre Brun, Benjamin Corre - have been able to highlight the predominant role of salt tectonics during Pyrenean rifting. Their simulations suggest that many geological observations (high-temperature metamorphism, socle/cover decoupling, crustal deformation regime, roll-over or diapir basin formation) are primarily caused by the presence of pre-rift salt, and not by other tectonic parameters which have been commonly invoked (thermal regime, stretching speed, rheology, etc.). Triassic evaporites allowed thick pre- and syn rift sedimentary series to remain in the central part of the rift system, where crustal thinning and heating caused by mantle exhumation are prominent.

These results were achieved using high-resolution numerical models, which could resolve deformations at the scale of the lithosphere as well as at the scale of the evaporite décollement layer.

This work was published in Basin Research in July 2019 and has been highlighted (“Editors' Choice”) for its innovative and provocative nature.

 

Reference : Duretz, T, Asti, R, Lagabrielle, Y, et al. Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn‐rift salt tectonics. Basin Res. 2019; 00: 116. https://doi.org/10.1111/bre.12389