TY  - JOUR
A1  - Insel, N.
A1  - Grove, M.
A1  - Haschke, Michael
A1  - Barnes, J. B.
A1  - Schmitt, Axel K.
A1  - Strecker, Manfred
T1  - Paleozoic to early Cenozoic cooling and exhumation of the basement underlying the eastern Puna plateau margin prior to plateau growth
JF  - Tectonics
N2  - 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 Ar-40/Ar-39 analyses of K-feldspar vary substantially. Basement rocks underlying the western Puna resided at temperatures below 200 degrees C (<6 km depth) since the Devonian (similar to 400 Ma). In contrast, basement rocks underlying the southeastern Puna were hotter (similar to 200-300 degrees C) throughout the Paleozoic and Jurassic and cooled to temperatures of <200 degrees C by similar to 120 Ma. The southeastern Puna basement records a rapid cooling phase coeval with active extension of the Cretaceous Salta rift at similar to 160-100 Ma that we associate with tectonic faulting and lithospheric thinning. The northeastern Puna experienced protracted cooling until the late Cretaceous with temperatures <200 degrees C during the Paleocene. Higher cooling rates between 78 and 55 Ma are associated with thermal subsidence during the postrift stage of the Salta rift and/or shortening-related flexural subsidence. Accelerated cooling and deformation during the Eocene was focused within a narrow zone along the eastern Puna/Eastern Cordillera transition that coincides with Paleozoic/Mesozoic structural and thermal boundaries. Our results constrain regional erosion-induced cooling throughout the Cenozoic to have been less than similar to 150 degrees C, which implies total Cenozoic denudation of <6-4 km.
Y1  - 2012
U6  - https://doi.org/10.1029/2012TC003168
SN  - 0278-7407
VL  - 31
IS  - 23
PB  - American Geophysical Union
CY  - Washington
ER  -