Ages and geochemistry of Mesozoic-Eocene back-arc volcanic rocks in the Aysén region of the Patagonian Andes, Chile

Strontium isotope variations in Middle Jurassic (Late Bajocian–Callovian) seawater: Implications for Earth's tectonic activity and marine environments

“…The enhanced magmatic activity related to the breakup of Gondwana of the age 170-160 Ma, which followed the formation of the KarooFerrar igneous province, is also reported from Patagonia and Antarctic Peninsula (Féraud et al, 1999;Parada et al, 2001;Hunter et al, 2004). The same applies to the back-arc volcanism of Crimea (Meijers et al, 2010) and NE Mexico (Rubio-Cisneros and Lawton, 2011).…”

Precious metal-bearing epithermal deposits in western Patagonia (NE Lago Fontana region), Argentina

“…These studies allowed establishing with precision the stratigraphy and the geochronology of the different Mesozoic volcanic events and their hydrothermal mineralizations associated (Parada et al, 2001;Hervé et al, 2007;Suárez et al, 2008). Therefore, the Chilean Jurassic-Cretaceous volcano-sedimentary stratigraphy can be well correlated with that of the Argentinian side.…”

“…The Divisadero Group of Chile, which correlates with the Ñirehuao and El Gato Formations in Argentina, was dated by Pankhurst et al (2003) obtaining ages between 118 and 116 Ma for acid ignimbrites, while Suárez et al (2008) got 118.5 AE 0.8 and 116.7 AE 0.7 Ma for similar rocks using UePb SHRIMP. The Ñirehuao Formation was analyzed using 40 Are 39 Ar method by Parada et al (2001) who obtained an age of 96.3 AE 1 Ma. This Cretaceous magmatism is closely associated with several hydrothermal ore deposits in Chile, such as Cerro Bayo Mine in Laguna Verde area, where adularia from epithermal veins was dated at 114-111 Ma by the 40 Are 39 Ar method (Poblete et al, 2011).…”

Paleomagnetism and geochemistry from the Upper Cretaceous Tres Picos Prieto locality (43ºS), Patagonian Plateau Basalts

“…Espinoza et al (2010) suggest that the genesis of middle Miocene basalts and andesites cropping out in the foreland at 47°S is related to an event of slab shallowing. On the other hand, Parada et al (2001) conclude that extensional tectonics is likely the explanation for the origin of the Late Cretaceous volcanism in the Aysén region in southern Chile. Thus, proposed models allow regarding the backarc basalts in Patagonia as a long lived, polygenetic magmatic province.…”

“…Noting the difficulties to invoke slab window models for all of the lavas, Parada et al (2001) discussed the origin of the Upper Cretaceous back-arc basalts in the general terms of extensional tectonics, adding that observed compositional variations between different localities in the Aysén region can be attributed to different degree of lithospheric stretching. Construction of plateau basalts in Patagonia began soon after the first contractional episode of the Andean Cycle (ca.…”