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Exhumation pulses in the Southern Patagonian Andes (Torres del Paine, 51°S)

The Cenozoic exhumational evolution of the Southern Patagonian Andes and its potential tectonic and climatic controls remain poorly constrained. Here, we integrate 21 new and 73 published bedrock thermochronological ages with 3D thermo-kinematic modelling (Pecube) to quantify exhumation pulses in the Torres del Paine area. This approach is used to identify temporal and spatial variations in exhumation rates before and after the start of Late Miocene glaciation. Our new AHe and ZHe ages range from 1.3 ± 0.7 Ma to 6.8 ± 1.6 Ma and from 13 ± 2.5 Ma to 86.3 ± 29.2 Ma, respectively. ZHe ages decrease westward with the youngest ages (~13 - ~19 Ma) being restricted to the deeply exhumed retroarc, which is in accordance with previous studies. Our numerical modelling results indicate that the distribution of observed thermochronologic ages can be explained by an up to 120 km-wide, parabolic-shaped exhumation pattern. Patagonian Andes


Nevena Andrić-Tomasevic, Sarah Falkowski, Alireza Aghakhani & Todd A. Ehlers
University of Tuebingen, Germany
GeoUtrecht 2020