Thermo-mechanical state of the Central Andes in the Altiplano-Puna region

IBARRA, FEDERICO; PREZZI, CLAUDIA BEATRIZ; SIPPEL, J.; SCHECK-WENDEROTH, M.; STRECKER, MANFRED

Congreso; XVII Reunión de Tectónica; 2018

The Central Andes and its associated basins are a complex and heterogeneous system. Its present-day state is the result of interaction between the Andean orogeny and inherited lithospheric structures. The resultant configuration plays a key role in the thermo-mechanical behavior of the system. A wide variety of geological and geophysical studies have been conducted, shedding light on the lithospheric structure of the region, and several studies have attempted to reconstruct the thermal and rheological state on a large scale through different modeling techniques, however, a regional scale, detailed and data-based model has not yet been conducted. We developed a consistent lithosphere-scale 3D structural and density model of the region between 20-30°S, validated through forward modeling of the Bouguer anomaly. In a second step, we present data-constrained estimates on the thermal field and rheological behavior based on our model and other databases, using different methodologies. We calculated depths to the Curie isotherm using the method presented by Bhattacharyya & Leu (1975); analyzed the earthquake distribution in the crust as a proxy for rheological behavior following the approach in Albaric et al. (2009); and derived effective elastic thicknesses from our model and gravity data using a Python code (Soler, 2015) based on methods developed by García et al. (2014). Integration of our model together with the temperature and rheology estimates allow us to analyze deformation patterns in the region and give us a better understanding on the present-day thermo-mechanical state of the system and the processes leading to it.