The Bajo Grande Basin: Late Jurassic(?)-Early Cretaceous syn-orogenic depocenters in southwestern Gondwana

• Published in: Tectonophysics
• Main Authors: Perez Frasette, Maximiliano Jose, Navarrete Granzotto, César Rodrigo, Bastías Silva, Joaquín, Valle, Mauro Nicolás, Chew, David, Iglesias, Maximiliano Lujan, Suárez, Manuel, Márquez, Marcelo, Drakou, Foteini, Folguera, Andrés
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Science
• Subjects: Patagonia; Intraplate; Contraction; Tectonic inversion; https://purl.org/becyt/ford/1.5; https://purl.org/becyt/ford/1; San Juan; Argentina; Perez; Rocas; Navarrete; South Atlantic Ocean
• Online Access: http://hdl.handle.net/11336/230811

In recent years, multiple Mesozoic episodes of crustal shortening and extension have been documented throughout Patagonia. These findings unveil a complex history of regional intraplate tectonic deformation. Nevertheless, there are numerous sectors in this vast region that have yet to undergo in-depth tectonic investigations, and hence aspects of its evolutionary history remain elusive. We present herein a comprehensive dataset comprising geophysical data (2D seismic lines), field data (detailed geological mapping and lithofacies analysis), and Usingle bondPb geochronological data (LA-ICP-MS and SHRIMP zircon ages) from a key region in southern Patagonia, known as the Bajo Grande area, located in the center of the Deseado Massif. The datasets support the hypothesis of a Late Jurassic(?) to Early Cretaceous shortening event that led to the tectonic inversion of former Jurassic (or may be older) extensional depocenters. This episode promoted the syn-inversion (syn-orogenic) deposition of Late Jurassic(?)-Early Cretaceous (140 ± 3 Ma) epiclastic and pyroclastic rocks within NNE-striking depocenters. These rocks are part of the Bajo Grande Formation, representing one of the oldest documented syn-orogenic sequences in southern Patagonia. This shortening event may have been triggered by a far-field response to the opening of the Rocas Verdes basin and to the rift-drift transition of the South-Atlantic Ocean. Fil: Perez Frasette, Maximiliano Jose. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Navarrete Granzotto, César Rodrigo. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Bastías Silva, Joaquín. Universidad Nacional de la Patagonia "san Juan Bosco". Facultad de Cs.naturales - Sede Comodoro. Cátedra de Geología Historica; Argentina. Eidgenossische Technische Hochschule zurich (eth Zurich); . Trinity College Dublin; Irlanda ...