Paleomagnetism in the Precordillera of northern Chile (22°30’S): implications for the history of tectonic rotations in the Central Andes

New paleomagnetic data from the northern Puna and western Cordillera Oriental, Argentina: a new insight on the timing of rotational deformation

“…This suggests that, close to the time when rotational deformation ceased in the Altiplano-Puna, the external part of the orogen started to rotate. This is in agreement with paleomagnetic observations from the forearc, which suggest that significant tectonic rotations roughly encompass the variable timing of local contractional deformation in the southern Central Andes (Roperch et al, 2000;Somoza and Tomlinson, 2002).…”

“…Paleomagnetically detected rotations show an overall consistency with this prediction (see compilations in Somoza et al, 1996;Randall, 1998;Beck, 1998;Prezzi and Alonso, 2002). However, the growing paleomagnetic database is showing a more complicated pattern, as dictated by variations in magnitude and timing of rotations (Somoza et al, 1996;Roperch et al, 2000;Somoza and Tomlinson, 2002;Rousse et al, 2003).…”

“…However, this kind of models also requires passive rotation of the forearc at these latitudes (e.g. Isacks, 1988;Kley, 1999) in contrast with paleomagnetic results from lower Miocene rocks in the forearc, which indicate negligible Neogene rotation (Roperch et al, 2000;Somoza and Tomlinson, 2002). These apparently conflictive observations remark the still scarce paleomagnetic and structural information to model the Neogene evolution of the Central Andes.…”

The Basal Penguin (Aves: Sphenisciformes) Perudyptes devriesi and a Phylogenetic Evaluation of the Penguin Fossil Record

“…During the Eocene, Quebrada Perdida would have been located at a paleolatitude nearly equivalent to the 14u349S present-day latitude, as there has been essentially no latitudinal translation of the area since the late Jurassic (Jesinkey et al, 1997;Somoza and Tomlinson, 2002;Hartley et al, 2005). Cold-water upwelling along the western coast of Peru appears to have been in place by the Late Cretaceous or early Tertiary (Keller et al, 1997), and this ''proto-Humboldt'' current may have influenced low-latitude penguin diversity by cycling cold, nutrient-rich water into the ecosystem (Clarke et al, 2007).…”

The Lautaro Basin: A record of inversion tectonics in northern Chile

“…In the other hand, the Paleogene deformation is more widely distributed across the Andes of northern Chile (Arriagada et al, 2000(Arriagada et al, , 2003(Arriagada et al, , 2006bTaylor et al, 2007). Eocene-Oligocene deformation was accompanied by tectonic shortening, mountain uplift and significant clockwise block rota tions (e.g., Hartley et al, 1992;Riley et al, 1993;Forsythe and Chisholm, 1994;Randall et al, 1996;Taylor et al, 1998;Arriagada et al, 2000;Somoza and Tomlinson, 2002;Arriagada et al, 2003Arriagada et al, , 2006bArriagada et al, , 2008. Fission track thermochronology indicates that tectonic uplift and erosion were mainly active during the EoceneEarly Oligocene 'Incaic Orogeny', when at least 4-5 km of rocks were eroded during exhumation of tectonic blocks of the Cordillera de Domeyko between ca.…”