Active tectonics in southern South America: a general review about its development and mechanisms

ANDRÉS FOLGUERA; GUIDO GIANNI; LUCÍA SAGRIPANTI; EMILIO ROJAS VERA

Busan

Congreso; 5th International INQUA Meeting on Paleoseismology, Active Tectonics and Archeoseismology (PATA); 2014

INQUA focus group on paleoseismology and active tectonics

Abstract: A range of processes acted during the Quaternary producing topography from the Chilean coast, where the Pacific ocean floor is being subducted, to the Brazilian-Argentinean Atlantic platform area: On one hand, active mountains in the passive margin whose origin is discussed; and on the other hand, processes associated with the activity of the eastern Andes, highly active at the Subandean region bordering the Altiplano plateau and at the Pampean flat subduction zone. We focus our analysis in the southern Central and Patagonian Andes, where orogenic processes are linked to particular mechanisms: i) impact of mantle plumes and local weakening of the lithosphere that yield under horizontal stresses producing active deformational zones, ii) dynamic topography associated with the opening of asthenospheric windows during the subduction of the Chile ridge and slab tearing processes, with the development of active extensional troughs, and iii) subduction of oceanic plateaus determining out-of-sequence active thrust fronts.