Thermochronological constraints of the exhumation and uplift of the Sierra de Pie de Palo, NW Argentina

Abstract

The Sierra de Pie de Palo located between 67 degrees 30'-68 degrees 30' W and 31 degrees 00'-32 degrees 00' S in the Argentine Western Sierras Pampeanas in Argentina is a distinct basement range, which lacks thermochronological data deciphering its exhumation and uplift history below 200 degrees C. Integrated cooling histories constrained by apatite fission-track data as well as (U-Th)/He measurements of zircon and apatite reveal that the structural evolution of this mountain range commenced during the Late Paleozoic and was mainly controlled by tectonically triggered erosion. Following further erosional controlled exhumation in a more or less extensional regime during the Mesozoic, the modern topography was generated by denudation in the Paleogene during the early stage of the Andean deformation, whereupon deformation propagated towards the west since the Late Mesozoic to Paleogene. This evolution is characterised by a total of 3.7 -4.2 km vertical rock uplift and by 1.7-2.2 km exhumation with a rate of 0.03-0.04 mm/a within the Sierra de Pie de Palo since ca. 60 Ma. Onset of uplift of peak level is also referred to that time resulting in a less Pliocene amount of uplift than previously assumed. (C) 2013 Elsevier Ltd. All rights reserved.