Cenozoic tectonic evolution in the Central Andes in northern Chile and west central Bolivia: implications for paleogeographic, magmatic and mountain building evolution

Cenozoic tectonostratigraphic evolution and architecture of the Central Andes in northern Chile based on the Aquine region, Western Cordillera (19°-19º30’ S).

“…1), is obscured by widespread Neogene volcanic products of the Andean Central Volcanic Zone, limiting our access and understanding of the Mesozoic, Paleogene and even Neogene Andean structural history in this area. Within this sector, the geology of the Western Cordillera and Precordillera indicates a complex history of long-lived compressive tectonics, which includes middle Eocene deformation (Incaic compressive phase) (e.g., Steinmann, 1929;Cornejo et al, 2003;Charrier et al, 2007;, which has been correlated with a significant increase in the velocity of plate convergence during this epoch (Pardo-Casas and Molnar, 1987), and possibly an Early to Late Cretaceous compressive event (Peruvian phase, e.g., Steinmann, 1929;Jaillard, 1992;Bascuñán et al, 2015) and a Late Cretaceous-early Cenozoic compressive event (K-T phase; Cornejo et al, 2003;Charrier et al, 2007Charrier et al, , 2009Charrier et al, , 2013.…”

“…30-20 Ma (Pardo-Casas and Molnar, 1987;Somoza, 1998). Since this time, two deeply-rooted, orogen-scale thrust systems, with opposite vergences and NNW-SSE to N-S trends, developed aligned and along both the Western Cordillera and Precordillera (Charrier et al, 2013) (Fig. 2), with the West-Vergent Thrust System (WTS) located within the Precordillera (Muñoz and Charrier, 1996;Victor et al, 2004;Farías et al, 2005;García and Hérail, 2005;García et al, 2011) and the East-Vergent Thrust System (ETS) located within the Western Cordillera, in the presentday arc Farías et al, 2005;Cortés et al, 2012a).…”

“…2), with the West-Vergent Thrust System (WTS) located within the Precordillera (Muñoz and Charrier, 1996;Victor et al, 2004;Farías et al, 2005;García and Hérail, 2005;García et al, 2011) and the East-Vergent Thrust System (ETS) located within the Western Cordillera, in the presentday arc Farías et al, 2005;Cortés et al, 2012a). These systems controlled the Neogene structural and depositional evolution of this part of the Andes (Charrier et al, 2007(Charrier et al, , 2013 García et al, 2004García et al, , 2011Charrier et al, 2007Charrier et al, , 2013Cortés et al, 2012a García et al, 2011), exerting a substantial role in the construction of the present-day relief of the region (Muñoz and Sepúlveda, 1992;Muñoz and Charrier, 1996;Pinto et al, 2004;Victor et al, 2004;Charrier et al, 2005;Farías et al, 2005;Jordan et al, 2010;Cortés et al, 2012a, b). Nonetheless, the detailed temporal and geometrical interrelationship of these structural systems has not yet been well established, nor the role they have played in controlling the lithostratigraphy and structure of the region lying between them.…”

“…These compressive events include: the Early to Late Cretaceous "Peruvian" phase; the Late Cretaceous-early Cenozoic "K-T" phase; the middle Eocene "Incaic" phase; the late Oligocene-Early Miocene "Quechua" phase, and the late Miocene "Pehuenche" phase (e.g., Steinmann, 1929;Mégard, 1984;Jaillard, 1992;Gregory-Wodzicki, 2000;Cornejo et al, 2003;Arriagada et al, 2006;Hoke et al, 2007;Charrier et al, 2007Charrier et al, , 2009Charrier et al, , 2013Farías et al, 2010). The phases are interpreted as a product of changing plate convergence conditions through time, and consequent deformation of the leading edge of the continental plate (Charrier et al, 2007(Charrier et al, , 2013. Specifically, the Oligocene-Miocene Quechua event has been correlated with breakup of the Farallon plate into the Nazca plate and an associated increase in the convergence rate (PardoCasas and Molnar, 1987;Somoza, 1998;Reutter, 2001).…”

“…In a constant attempt to unravel the evolution of Andean uplift, numerous studies have taken place along this long-lived, subduction-related, cordillerantype mountain belt (sensu Dewy and Bird, 1970), of which many have focused on the formation of the Altiplano plateau (e.g., Isacks, 1988;Allmendinger et al, 1997;Lamb et al, 1997;Gregory-Wodzicki, 2000;Elger et al, 2005;McQuarrie et al, 2005;Barnes et al, 2008;Barnes and Ehlers, 2009;Hartley and Evenstar, 2010;Jordan et al, 2010;Charrier et al, 2013;Garzione et al, 2014). Crustal thickening by horizontal shortening and associated deformation has been evoked as a prime mechanism for mountain building throughout the western margin of South America (Isacks, 1988;Allmendinger et al, 1997) and for bending of the Bolivian orocline (e.g., Isacks, 1988;Arriagada et al, 2008).…”