Absolute age of deformation and duration of folding in the Southern Pyrenees from U-Pb dating of calcite veins

Dating fold-related structures is critical to understand the timing, duration, and rate of fold growth as well as the sequential evolution of fold-and-thrust belts. In this contribution, we combine structural analysis of fractures with U-Pb dating of calcite veins related to the evolution of the Bóixols-Sant Corneli anticline (Southern Pyrenees) aiming to constrain the age and evolution of deformation and the duration of folding. Twenty-three U-Pb ages were obtained in the different sets of fracture-filling calcite veins, which span from Late Cretaceous to late Miocene (79.8 ± 1.2 Ma to 9 ± 4.6 Ma). These ages have been attributed to growth (71.2 to 56.9 Ma), fold tightening (55.5 to 27.4 Ma) and collapse (20.8 to 9.0 Ma) of the Bóixols-Sant Corneli anticline. This reveals a duration of 14 Myr for the folding stage and 28 Myr for the fold tightening, which translates in 42 Myr of the entire folding process and thus encompassing most of the Pyrenean compression.