Lower Jurassic to Early Paleogene Intraplate Contraction in Central Patagonia

Abstract

Breakup and dispersion stages of Gondwana were ruled by crustal extension. In Patagonia, this regime was associated with the opening of extensional basins from the Jurassic onward, a process that was interrupted by the Andean Orogeny. New data generated from the hydrocarbon exploration allowed identifying Jurassic to Eocene contractional deformations, previously not registered in Central Patagonia. We summarize in this chapter evidence of five compressional events intercalated with the extensional regime that affected Central Patagonia from the Early Jurassic to the Paleogene. These events, denominated “C1,” “C2,” “C3,” “C4,” and “C5,” acted diachronicronously producing tectonic inversion of the Jurassic–Cretaceous depocenters. The first three contractional pulses occurred during the Jurassic, while the two remaining were Late Lower Cretaceous and Early Paleogene. The origin of this compressive activity would be linked to different processes that comprehended from thermal weakening of the crust produced by expansion of the Karoo thermal anomaly in Mid- to Late Jurassic times; the southward continental drift since the Early Jurassic; the ridge push generated by the opening of Weddell Sea since Mid-Jurassic times; and two mid-ocean ridge collisions during the Cretaceous.