Miocene block uplift and basin formation in the Patagonian foreland: The Gastre Basin, Argentina

The North Patagonian orogenic front and related foreland evolution during the Miocene, analyzed from synorogenic sedimentation and U/Pb dating (∼42°S)

“…K-Ar and Ar-Ar determinations had initially assigned this interval to the middle to late Miocene Mazzoni and Benvenuto, 1990). However, Ar-Ar ages obtained from condensed sequences of the middle terms of the Collón Cura Formation in the Gastre Basin immediately to the east (Fig.3), yielded an age of 14.86 ± 0.13 Ma (Bilmes et al, 2013).…”

“…To the east, the North Patagonian Precordillera presents two contrasting sectors: a western zone where Oligocene to Miocene deposits are openly folded, and an eastern sector where Triassic depocenters and their Paleozoic basement are thrust on top of Paleogene to Neogene successions (Franzese and Spalletti, 2001;D'Elia et al, 2012;Bilmes et al, 2013). In this zone, Paleogene volcanic rocks are subdivided according to their age and facies distribution into an extra-Andean association in the east (Pilcaniyeu volcanic belt) with Paleocene to Eocene ages, and an Andean association to the west (Maitén volcanic belt), with Oligocene to early Miocene ages (Feruglio, 1941;Ramos, 1982;Rapela et al, 1983Rapela et al, , 1988).…”

“…Maximum ages determined in this work, interpreted as close to the depositional ages, and those recently released by Bechis et al (2014b) to the north between 41º and 41º30' S, are younger than those previously assigned to the Ñirihuau and Collón Cura formations, based on stratigraphic relationships and limited radiometric ages (Marshall et al, 1977;Cazau et al, 1989;Mazzoni and Benvenuto., 1990;Bilmes et al, 2013).…”

“…1) (Giacosa y Heredia, 2000, 2004Ramos et al, 2011;Orts et al, 2012;Bilmes et al, 2013;Bechis et al, 2014a;Huyghe et al, 2014). These works have described and analyzed synorogenic sequences of the Miocene Ñirihuau Basin, located next to the orogenic front area in an eastern broken foreland system.…”

Synorogenic foreland rifts and transtensional basins: A review of Andean imprints on the evolution of the San Jorge Gulf, Salta Group and Taubaté Basins

“…In particular, the Andes are the most important mountain system in an active subduction setting and currently hold the largest non-collisional orogenic plateau on earth (Barnes and Ehlers, 2009). In the past, Andean far-field stresses have effectively propagated throughout the foreland area, locally upthrusting basement blocks and inverting rift basins located on-and offshore of eastern Brazil, Central Andes and Patagonia (Homovc et al, 1995, Bilmes et al, 2013, Cobbold et al, 2001, Marques et al, 2014, Nogueira et al, 2015. Moreover, focal plane mechanisms of thrust faulting on the Brazilian margin occurs hundreds of kilometers off the Andean deformational zone, showing that the foreland area is sensitive to the plate interactions occurring at the Pacific margin (Assumpção, 1998).…”