Growth of the Patagonian Andes since the Mid Jurassic to the Present

ANDRÉS, FOLGUERA; GIANNI, GUIDO; NAVARRETE, CÉSAR; ECHAURREN, ANDRÉS; ORTS, DARÍO; FERNÁNDEZ PAZ, LUCÍA; IANNELLI, SOFÍA B.; LITVAK, VANESA D.; ENCINAS, ALFONSO

Concepción

Congreso; XV Congreso Geológico Chileno; 2018

Universidad de Concepción

The Patagonian Andes have been constructed through several deformational stages. Thus, Jurassic within plate contractional................ ........ ...................... .......... ................ ...... .................... ...................... .......... ........ ........................ ...... ........ .......................... ........ .................... .......................... .................. .................. ............ .......................... ........ .................... ...... .... ...................... ............................ .......... ................ ...... ........ ..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................associated with a stable seismic ridge impacting at the Patagonian trench. These Cretaceous contractional structures are affectedby Eocene deformations that are variable in mechanics depending on the latitude: While some segments of the fold and thrustbelt are extensionally reactivated, others are contractionally reactivated. This variable behavior is interpreted as due to the obliquecollision of a seismic ridge from north to south that produced slab windows alternated with segments where transform segments.................... .............. .............. ...... .................... .................... ...... ............................ ...... ...................... .................... .......... ............ ........ .................... .............. ........the outstanding detachment of Los Chonos fore-arc sliver. This extensional stage ends at the earliest Miocene with Atlantic and..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................fold and thrust belt that reaches Central Patagonia in mid-Miocene times. This process is accompanied by mild east-ward arcmigrations at the edges of the Chonos accretion zone interpreted as subducted slab shallowing. Late Miocene deformation isfocused on out-of-sequence thrusts that produce the rain shadow conditions that characterize Patagonia producing strong biotachanges. Mild Quaternary reactivations of the Miocene systems are the late expression of this uplift.