Abstract

The Devonian in Argentina is distributed in three basins which have had no intracontinental connections. The Northwest and the Cuyo basins opened into the Pacific, whereas in Patagonia, the Submarine Platform, Malvinas and Buenos Aires the Devonian may have been of Atlantic origin. In the Northwest Basin, sediments rarely reach the Middle Devonian. In the Cuyo Basin and the Patagonian-Atlantic province, deposition reaches well into this time. The northwestern Devonian is arenaceous and shales out eastward. It reaches unusual thicknesses in the Eastern Cordillera foothills. The Cuyo Basin with a definite and well recognized eastern border shows typical eugeosynclinal flysch-type sedimentation. These transgressions came in from the north-northwest. Tectogenesis was strong in Cuyo and Buenos Aires, whereas in the Northwest Basin deformation is very gentle or missing. In Cuyo the late Devonian to Early Carboniferous disturbances gave rise to the Protoprecordillera. In every one of the recognized basins numerous formations are described: Baritu, Arroyo Colorado, Tonono, Rincon, Cabure and Copo for the Northwest Basin, all of Early Devonian age. In the Cuyo Basin, Talacasto, Punta Negra, Villaviciencio, Tontal, Lomitas Negras, Hilario, are of Early Devonian age and Ramadita and Punilla of Early to Mid-Devonian age. In Buenos Aires, the Bravard, Naposta, Providencia and Lolen formations belong to the Lower Devonian. In Malvinas, Port Stephens and Fox Bay are Lower Devonian, whereas Monte Maria could range into Mid-Devonian time.