Patagonian broken foreland and related synorogenic rifting: The origin of the Chubut Group Basin

Exhumation of the Neuquén Basin in the southern Central Andes (Malargüe fold and thrust belt) from field data and low-temperature thermochronology

“…It is proposed that i) rapid and anomalously wide migration of the orogenic front towards the continental interior follows arc expansion that modifies the thermal and therefore the mechanical structure of the lithosphere, favoring shortening; followed by ii) shut down of arc magmatism producing a volcanic arc gap, and consequent "refrigeration" of the upper plate through removal of the mantle wedge and lowering of basal heat flow. Fossil shallow subduction settings along western South America have been proposed on similar grounds: anomalous foreland deformation and arc expansions/migrations (James and Sacks, 1999;Kay et al, 2006;Ramos and Folguera, 2005;Kay and Coira, 2009;Espinoza et al, 2010;Ramírez de Arellano et al, 2011;González Guillot et al, 2011;Spagnuolo et al, 2012;Gianni et al, 2015, Fennell et al, 2015.…”

“…Recently, there has been increasing evidence and discussion about the role of shallow and flat subduction settings in the construction of the Andes and North American cordillera (Murphy et al, 1998;James and Sacks, 1999;Ramos and Folguera, 2009;Kay and Coira, 2009;De Celles et al, 2009;Martinod et al, 2010;Dávila and Cárter, 2013;Gianni et al, 2015, Fennell et al, 2015. These models have to a certain extent, explained the pattern of magmatic variability through time as a product of changes in the angle of subduction.…”

“…Inset in the lower right-hand corner indicates the categories in which exhumation ages derived from fission track data were divided. The deformational front is based on Gianni et al (2015) and Fennell et al (2015). Note that most of thermochronological data are located on the western Andean side.…”

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

“…Thus, the Chubutian stage of the San Jorge Gulf Basin responded to a contractional stress field related to Andean orogenesis to the west and to extensional-transtensional tectonics mainly in the eastern sector (Hechem and Strelkov, 2002). To the west, the Chubut Group deposited in a broken foreland basin in response to the Andean contractional uplift, as revealed by subsurface (seismic) and surface recognition of syn-contractional growth strata in all units belonging to this group (Homovc et al, 2011 Gianni et al (2014Gianni et al ( , 2015 proposed that the San Jorge Gulf Basin would have mimicked at a smaller scale, the mechanics of collision-related rifts. As hypothetically envisaged by Sengör, (1978), in these cases a preexistent rift basin oriented parallel to the maximum horizontal stress (σ1) could be reactivated in an extensional/transtensional mode.…”

“…As hypothetically envisaged by Sengör, (1978), in these cases a preexistent rift basin oriented parallel to the maximum horizontal stress (σ1) could be reactivated in an extensional/transtensional mode. Gianni et al, (2015) argued that the source of a strong contractional stress-field during Cretaceous times was associated to a slab swallowing event, instead of a micro-continent collision needed to induce impactogenesis Barcat et al, 1989;Bruni et al, 2008Suarez et al, 2009b, Sylwan et al, 2001and Suarez et al, 2013. The D-129, Castillo and lower member of Bajo Barreal Fms.…”