Dec 22, 2012 - Geologic map of part of the Puna plateau margin in northwest ..... 2012tc003168. Other auxiliary material files are in the HTML. doi:10.1029/.
Paleozoic to early Cenozoic cooling and exhumation of the basement underlying the eastern Puna plateau margin prior to plateau growth N. Insel,1,2 M. Grove,3 M. Haschke,4 J. B. Barnes,5 A. K. Schmitt,6 and M. R. Strecker1 Received 11 June 2012; revised 18 October 2012; accepted 26 October 2012; published 22 December 2012.
[1] Constraining the pre-Neogene history of the Puna plateau is crucial for establishing the initial conditions that attended the early stage evolution of the southern extent of the Andean plateau. We apply high- to low-temperature thermochronology data from plutonic rocks in northwestern Argentina to quantify the Paleozoic, Mesozoic and early Tertiary cooling history of the Andean crust. U-Pb crystallization ages of zircons indicate that pluton intrusion occurred during the early mid-Ordovician (490–470 Ma) and the late Jurassic (160–150 Ma). Lower-temperature cooling histories from 40Ar/39Ar analyses of K-feldspar vary substantially. Basement rocks underlying the western Puna resided at temperatures below 200 C (
