Iberian-Europe Convergence: Evolution of the Cretaceous and Eocene Basins in Pyrenees and Provence

J. Muller, L. Ducassel, G. Guieu, P. Razin, J. Rochet, J. Roussel, P. C. Velasque, M. Villeneuve

During Cretaceous time the geodynamic evolution of Northern and Western Pyrenean basins was related to scissors-shaped rifting which evolved as a passive margin filled by thick flysch deposits. In Provence, the carbonate platform was marked since the late Albian by the arrival of significant detrital flows originated from an uplifted Paleozoic block situated in the Gulf of Lion. The N20 to N30 Pamplona and Toulouse transform faults and their N30 to N40 Provencal equivalents are major features of the Cretaceous basins since they control both the facies and the thickness of deposits. In Provence the northward migration of the basin from Cenomanian to Eocene and Oligocene indicates the growing of the Gulf of Lion-South Provence crustal uplift and its northward displacement. he Cretaceous opening of the western Pyrenean, Parentis, and Bay of Biscay basins is synchronous with the first stages of compression in the Gulf of Lion. These features are induced by the rotation of Iberia.

During the Eocene the compression, resulting from the Iberian-Europe convergence, affected nearly the whole Pyrenean-Provencal area. In the southern part of the Pyrenees east of the Pamplona fault, the successive dislocations of carbonate platforms, migration of reefs, and filling of foreland basins became the signature of the intracontinental subduction of Iberia. The transform fault pattern, still well preserved in spite of the Eocene compression, prevents any important strike-slip movement between Europe and Iberia, especially along the so-called North Pyrenean fault zone, which shows several discontinuities in the western part of Pyrenees. The final evolution of Gulf of Lion crustal uplift generated a gliding of its cover (Provence overthrusts) and, during Oligocene, the opening of the Ligurian-Provencal basin by a propagating rift process.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.