Retroarc deformation and exhumation near the end of the Andes, southern Patagonia

Phylogenetic insights into Andean plant diversification

“…Such nonuniform spatial patterns of uplift have also been suggested for the Northern Andes (Hoorn et al, 1995). For the Southern Andes, Blisniuk et al (2005) indicates that most of the uplift would have occurred by 16.5 Ma, earlier than most of the Central Andes, and several studies are in line with the idea of an Early Miocene uplift of the Southern Andes (e.g., Jordan et al, 2001;Encinas et al, 2013;Fosdick et al, 2013), but Late Miocene phases of uplift have also been reported for the northern Patagonian Andes (Ramos et al, 2014).…”

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

“…This estimation agrees with the proposed timing for the beginning of the 'Quechua Phase' of Andean tectonics around 19-18 Ma (Malumián and Ramos, 1984;Ramos, 1989;Marshall and Salinas, 1990a;Ramos and Kay, 1992;. Additionally, this interpretation is supported by the synchronous acceleration of exhumation rates across the Patagonian Andes (Thomson et al, 2001), estimated to have occurred between 17-14.24 Ma by Blisniuk et al (2006), and between 22-18 Ma by Fosdick et al (2013) in the retro-foreland region. The dynamic Oligocene-Miocene tectonic configuration of the Patagonian Andes generated by: 1. changes in the subduction velocity, convergence rate, and obliquity of the Nazca and South American plates (Pardo-Casas and Molnar, 1987); and 2. an increase in compression and shortening related to the collision of an unstable oceanic spreading center (quadruple junction) at 18-17 Ma (Breitsprecher and Thorkelson, 2009;Eagles et al, 2009), followed by the subduction and northward migration of the Chile Ridge (Cande and Leslie, 1986;Lagabrielle et al, 2004), seem to be the primary factors triggering the uplift, concomitant widening and foreland propagation of the fold-and-thrust belt during Early Miocene times (Ramos and Ghiglione, 2008).…”

Constraints on deformation of the Southern Andes since the Cretaceous from anisotropy of magnetic susceptibility

“…Although the geological record from this region is not complete enough to assess whether the main tectonic events have been synchronous across the Patagonian and Fuegian Andes, a partial time overlap of some deformational episodes within the two domains during the Cenozoic (Cande and Leslie, 1986;Thomson et al, 2011;Somoza and Ghidella, 2012;Fosdick et al, 2013) appears to be compatible with our AMS results.…”

“…A major thrusting event and uplift in the Paleogene has been also constrained using zircon (U-Th)/He dating from the eastern domains of the southern Patagonian Andes (Fosdick et al, 2013). The Eocene tectonics became much stronger towards the south affecting in particular Tierra del Fuego due to fast ~NE-directed subduction of the Phoenix plate between 47-28 Ma (Ramos and Aleman, 2000;Olivero and Martinioni, 2001;Kraemer, 2003;Ghiglione and Ramos, 2005;Ghidella, 2005, 2012;Ghiglione and Cristallini, 2007).…”

“…11 Thomson et al, 2001), which then propagated to the east during the early Miocene (22-18 Ma; Fosdick et al (2013) and middle to late Miocene (12-8 Ma; Thomson et al, 2001). …”