Chronology From Rifting To Foreland Basin in ahe Paganzo Basin (argentina), And A Reapprisal On The "eo- and Neohercynian" Tectonics Along Western Gondwana.

ASTINI R.A.; MARTINA, F.; EZPELETA, M.; DÁVILA, F.D.; CAWOOD, P.A.

Santiago ,Chile

Congreso; XII Congreso Geológico Chileno; 2009

Universidad de Santiago Chile y Asociación Geológica de Chile

Analysis of the Paganzo Basin (Argentina), incorporating new isotopic and provenance data, provides the basis for an integrated model of the evolution of the southern Central Andes from Early Carboniferous rifting to commencement of the late Permian Choiyoi granite-rhyolite silicic magmatic province. Tectonic switching in the Terra Australis peri-Gondwanan accretionary orogen within this segment of the Andes can be related to the following sequence of events: collision of Chilenia (~385 Ma), post-collisional extension (360-335 Ma) (“Eohercynian”), initiation of subduction along the Chilean trench (~325 Ma), strong compression and coupling in an Andean-type setting (the San Rafael Orogeny) with progressive shallowing of the subducting slab (305-270 Ma) (“Eohercynian”), and final slab break-off around 260 Ma enhancing the Choiyoi granite-rhyolite silicic magmatic province.