The Making of a Fold-Thrust Belt 

Pyrenees: From Mesozoic salt tectonics and hyperextension to Eocene compression

The Pyrenees are an Alpine fold-thrust belt formed during the Late Cretaceous–early Miocene as the result of south-to-north continental collision of the Iberian and European plates. The Pyrenean orogeny inverted a precursor rift, that was an east-west-trending aborted branch of the Mid Atlantic spreading ridge that opened from the Jurassic to Late Cretaceous, connecting the Atlantic and the Tethys oceans. A cross section through the central Pyrenees has a fan like geometry with an axial antiformal stack of Variscan basement rocks flanked by both northward- and southward-directed cover thrust sheets detached above Triassic salt. New research shows that the Pyrenees are also an excellent lab for studying salt tectonics; see an advance in the paper: Rising and falling diapirs, shifting depocenters, and flap overturning in the Cretaceous Sopeira and Sant Gervàs subbasins (southern Pyrenees) by Saura et al., 2016, Tectonics.                As a novelty, this field trip incorporates an exhaustive examination of all available seismic data, constrained to surface geology.

October 4-8, 2021

  • The Variscan basement
  • Carboniferous-Triassic pre-salt extensional framework
  • Extensive red bed sedimentation
  • Late Triassic salt
  • Jurassic-Cretaceous salt tectonics regime and hyperextension
  • Reefal shallow-marine carbonate platforms
  • Latest Cretaceous-Eocene structural inversion
  • Analysis of thrust structures
  • Basin fill mechanisms in compressional settings
  • Fluvio-deltaic to turbidite depositional systems
  • Syn- and post-tectonic alluvial fan deposition