Multiple shallow subduction settings in the construction of the Southern Andes

FOLGUERA, A.; ROJAS VERA, E.A.; SAGRIPANTI, L.; SPAGNUOLO, M.; TOBAL, J.; RAMOS, M.; RAMOS, V. A.

Antofagasta

Simposio; VIII ISAG; 2012

During the last years increasing evidence and discussion about the role of shallow and flat subduction settings in the construction and destruction of the Andes and North American cordillera have emerged (James and Sacks, 1999; Kay et al., 2006; among others). These models have at a certain extent explained the pattern of magmatic variability through time as a product of changes in the angle of subduction. These subduction geometry variations are thought to have triggered heat flux changes, associated with injection and extrusion of important volumes of asthenospheric material, potentially accompanied by thermal and mechanical removal of the lower lithosphere. Deformational stages would have also been linked to these processes and associated withthe appearance of fragile/ductile transitions at the lower crust in the retroarc zone as arc expanded landwards (Spagnuolo et al., 2011), as well as with crustal delamination phenomena (Kay and Coira, 2009).