Evolution of the Stress Field Patterns during the Construction of a Subduction-Orogenic System: The Central Andean Stress Field Evolution Project (CAFE)

GIAMBIAGI, L.B.; SPAGNOTTO, S.; ALVAREZ, P.P.; QUIROGA, R.; JALDIN, D.; MESCUA, J.F.; BARRIONUEVO, M.; ECHAURREN, A.; BERTOA DEL LLANO, M.; SURIANO, J.; LOSSADA, A.; LOTHARI, L.

San Francisco

Congreso; AGU23; 2023

American Geophysical Union

The study of the stress field patterns during the evolution of a subducted-related orogenic system, from the early stages of compression to the formation of a large and heated plateau, is crucial for our understanding of plate tectonic processes.The Central Andes are the result of ~100 ma of contraction along an orthogonal-to-oblique convergent subduction zone of more than 3,500 km. Two models of orogenic evolution have been proposed: (i) a punctuated contractional-stage model, with three well-identified contractional periods in the Late Cretaceous, Eocene and Miocene-Quaternary; and, (ii) a continuous shortening model, at least for the last 45 ma, associated with a gradual crustal thickening and foreland migration of the deformation.To shed light on this discussion, we reconstruct the stress fields acting during the construction of the Andean orogenic system, and discuss the two proposed models for its evolution. Here we present a data base integrating the main structures with their kinematic and timing assigned, and more than 1,000 new and published stress tensors. We construct nine stress-field maps showing stress orientation and relative magnitude. These maps represent nine evolutionary stages during the orogenic construction, and allow the identification of three types of stages: stages dominated by tectonic stresses and characterized by compression along and across the orogenic system; stages dominated by gravitational stresses and/or stress partitioning and characterized by strike-slip and extension; and, stages with hybrid stress fields.