Sedimentary record of tectonic inversion and basin partitioning in the South-Central Pyrenees during the Late Cretaceous.

The tectosedimentary evolution of the Pyrenees is a well-known example of the interaction among growth strata, sediment routing, sequence stratigraphy and evolving depositional environments. During the Late Cretaceous a general tectonic inversion from rift to foreland basin is recorded. Such evolution is related to the Iberian plate kinematics and is evidenced by the substitution of carbonate systems by mixed and clastic ones, that will persist until Oligocene times.

The precise evolution and timing of the inversion stages is addressed by studying the Noguera Pallaresa river transect (composite Collegats -Font de la Plata section) which is further compared with other areas. This classical transect also permits to study successive structure reactivations after inversion started. Robust magnetostratigraphic results from several stratigraphic units (Font de les Bagasses marls, Riu Boix platform or Montsec sands) permit an accurate dating of the beginning of the inversion stage within the Santonian and also provide time constraints (together with absolute datings) for the rest of the Late Cretaceous. The role of the Montsec thrust as paleohigh controlling basin partitioning is also evidenced by a large paleocurrent database obtained from the Areny sandstone formation. Sedimentological data and carbonate microfacies determinations also provide refinements of the complex interaction between tectonic and climatic factors.

Finally, the combined biomagnetostratigraphic age model is compared with the peripheral areas of the foreland such as Serres Marginals, Eastern and Northern Pyrenees. It is strongly suggested that the formation of accommodation space for sedimentation due to the inversion was fully synchronous all over the orogen.