Rapid tectonic and paleogeographic evolution associated with the development of the Chucal anticline and the Chucal-Lauca Basin in the Altiplano of Arica, northern Chile

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

“…Within Neogene deposits, syntectonic eastward-fanning growth strata and progressive unconformities have been registered in the Chucal anticline (~18°45' S; Fig. 1b) (García et al, 2004;Charrier et al, 2005) and to the east of the study area, towards the Altiplano (Figs. 1b and 2) (Cariquima Region of 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.…”

“…The positive relief in the Aquine region would have restricted deposition of pyroclastic flows to depressed areas or prompted erosion of the deposits from topographic highs. In the Western Cordillera of the Belén Region, the Oligocene-Miocene explosive volcanic event is registered in the Lupica Formation (García et al, 2004;Charrier et al, 2005Charrier et al, , 2007Charrier et al, , 2013, which exhibits growth strata probably associated with normal faulting near the Oligocene-Miocene boundary, suggesting the existence of calderas along the present-day Precordillera and Western Cordillera (Charrier et al, 2013), likely to be the source of the pyroclastic deposits in the Oxaya and Utayane Formations.…”

“…3, García et al, 2004;Charrier et al, 2005Charrier et al, , 2013. In the Aquine region, the Miocene Mauque Formation represents the occurrence of humid alluvial fans and associated braided rivers throughout their middle and distal portions, developed in exoreic intramontane basins (Argandoña, 1984;Cortés et al, 2014;Valenzuela et al, 2014;Bobadilla, 2015;Herrera et al, 2015), adjacent to Middle and Upper Miocene volcanic edifices (Fig.…”

Depósitos burdigalianos de la Formación Santa Cruz en Sierra Baguales, Cuenca Austral (Magallanes): Edad, ambiente de deposición y vertebrados fósiles.

“…These faunas include from north to south: a. the Chucal fauna of the Chucal Formation in the Lauca Basin, northern Chile, dated between 19 and 17.5 Ma (Charrier et al, 2002;Croft et al, 2004Croft et al, , 2007; b. the enigmatic and imperfectly known Friasian fauna (Río Frías Formation) of Alto Río Cisnes, in the Aysén Region (Ameghino, 1906;Roth, 1908;Kraglievich, 1930;Marshall, 1990;Marshall and Salinas, 1990a;; c. the undated Pampa Castillo and Pampa Guadal faunas, in the northern portion of the Austral Basin, south of Lake General Carrera De la Cruz and Suárez, 2006;Bostelmann and Buldrini, 2012); and d. a handful of spatially unconnected mammal fossil-bearing deposits assigned to the Palomares Formation of the Austral Basin at Puerto Natales, Sierra Baguales, Laguna del Toro, Lake Blanco and Tierra del Fuego in the Magallanes Region (Keidel and Hemmer, 1931;Decat and Pomeyrol, 1931;Hemmer, 1935a;Simpson, 1941;González and Tapia 1952a 2 ; Marshall and Salinas, 1990b). Other localities undoubtedly containing Pansantacrucian faunas in Chile are the largely undescribed 'Las Leñas' fauna of central Chile, the only to have been formally considered as a Colhuehuapian age fauna ; and the Early Miocene basal sections of the CuraMallín Formation in the Laguna del Laja (Flynn et al, 2008;Luna et al, 2011;Shockey et al, 2012) and Lonquimay sub-basins Suárez et al, 1990;Suárez and Emparan, 1995;Croft et al, 2003;Buldrini and Bostelmann, 2011).…”