Density structure and rheology of northern Argentina: from the Central Andes to the foreland basin.

IBARRA, FEDERICO; MEESSEN, C.; LIU, S.; PREZZI, CLAUDIA BEATRIZ; SIPPEL, J.; SCHECK-WENDEROTH, M.; STRECKER, MANFRED; SOBOLEV, S.

Congreso; European Geosciences Union General Assembly 2018; 2018

The Central Andes along with their related basins constitute a heterogeneous and complex system. Its presentstate results from the interaction of the recent Andean orogeny with inherited structures of the lithosphere. Severalstudies have been conducted in the region, producing a variety of geological and geophysical data that shed lighton the lithospheric structure of the orogen and its foreland basins. Individual studies have integrated these datainto regional models, however, a data-based density model of northern Argentina has not yet been published. In ajoint effort, we present a consistent lithosphere-scale 3D structural and density model of northern Argentina that integrates two previously published models of the Central Andes and the Chaco-Paraná foreland basin. The gravity response of the combined model agrees with the observed Bouguer gravity field. In a second step, starting from this model, we present data-constrained estimates on the thermal field and rheological behaviour across northern Argentina.We address how the present-day thermal field can be estimated in a transient arc-backarc system, which problems arise and propose an approach to tackle them. Thermomechanical models using our validated subsurface structure then allow to analyse present-day and future deformation in northern Argentina. Together with the temperature and rheology estimates, a better understanding of the whole system and the processes leading to its present state is achieved. The model will be further used to reconstruct basin evolution and georesource formation.