Abstract
Apatite fission track data for Miocene plutons of the western slope of the Principal Andean Cordillera in central Chile (33-35°S) define a distinct episode of enhanced crustal cooling through the temperature range of the apatite partial annealing zone (~125-60°C) from about 6 to 3 Ma. This cooling episode is compatible with accelerated exhumation of the plutons at the time of Pliocene compressive tectonism, and mass wasting on the western slope of the Principal Andean Cordillera in central Chile. The timing coincides with the southward migration of the subducting Juan Fernandez Ridge and the development of progressive subduction flattening northward of 33°S. It also corresponds to the time of active magmatic-hydrothermal processes and rapid unroofing of the world class Rio Blanco-Los Bronces and El Teniente porphyry Cu-Mo deposits. Zircon fission track ages coincide with previous 40 Ar/ 39 Ar dates of the intrusions, and with some of the apatite fission track ages, being coherent with igneous-linked, rapid cooling following magmatic intrusion. The thermochronologic data are consistent with a maximum of about 8 km for Neogene exhumation of the plutons.
Highlights
The subduction-related Miocene-Pliocene volcanism and plutonism along the Principal Andean Cordillera of central Chile (33-35°S) developed synchronously with crustal thickening and tectonic uplift related to compressive tectonism (Miocene Quechua, and Pliocene Diaguita phases, described originally by Steinmann (1929) in Perú and by Salfity et al (1984) in northwestern Argentina; see the review of González-Bonorino et al, 2001)
This cooling episode is compatible with accelerated exhumation of the plutons at the time of Pliocene compressive tectonism, and mass wasting on the western slope of the Principal Andean Cordillera in central Chile
Apatite fission track ages from 3.2±0.7 to 21.1±3.4 Ma were obtained for eighteen samples from Miocene plutons that are spread on the western slope of the Principal Andean Cordillera of central Chile (33-35°S) and span elevations between 760 and 3,790 m (Table 2; Fig. 2)
Summary
The subduction-related Miocene-Pliocene volcanism and plutonism along the Principal Andean Cordillera of central Chile (33-35°S) developed synchronously with crustal thickening and tectonic uplift related to compressive tectonism (Miocene Quechua, and Pliocene Diaguita phases, described originally by Steinmann (1929) in Perú and by Salfity et al (1984) in northwestern Argentina; see the review of González-Bonorino et al, 2001). This Andean segment occurs immediately southeast of the place where the Juan Fernández Ridge is being subducted (Fig. 1), which has migrated from north to south during the Late Cenozoic (Yáñez et al, 2001, 2002). Understanding the Neogene exhumation history of the Principal Andean Cordillera of central Chile has implications for both the tectonic and metallogenic evolution of this segment of the Andean orogen
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
