Stress field evolution of the southernmost Andean Cordillera from paleostress analysis (Argentine Tierra del Fuego).
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2019Referencia bibliográfica
Maestro, A.; Ruano, P.; Torres-Carbonell, P.; Bohoyo, F.; Galindo-Zaldívar, J.; Pedrera, A.; Ruiz-Constán, A.; González-Castillo, L.; Ibarra, P.; López-Martínez, J.. Stress field evolution of the southernmost Andean Cordillera from paleostress analysis (Argentine Tierra del Fuego). Tectonics. 38 - 1, pp. 7 - 25. 2019.
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This work has been funded by projects CTM2011-30241-C02-02, CTM2014- 60451-C2-2-P and CTM2017-89711-C2- 2-P of the Spanish R&D National Plan and by PICT funding from ANPCyTFONCyT (Argentina).Resumen
The Argentine Tierra del Fuego comprises part of the roughly east-west trending southern end
of the Andean Cordillera intensely deformed since the Mesozoic. Mesostructures have been measured in
Late Jurassic to Miocene rocks. Taking into account statistical criteria to provide a representative stress
tensor from a fault population, this study defines 28 paleostress tensors pertaining to 22 sites. The orientation
of σ1 shows two main modes trending E-W to ESE-WNW and NE-SW. In addition, extensional sites reveal N-S,
NE-SW, ESE-WNW, and NW-SE horizontal σ3 and vertical σ1. The stress fields obtained are congruous with
a regional NE-SW compressive stress direction active in the study zone since the Late Cretaceous. Shortening
was coeval with a 30° counterclockwise rotation of the Patagonian orogenic curve and the indentation of the
orogenic wedge against a basement high, the Río Chico Arch, up to the early Miocene. The indentation
caused a modification in the orientation of the compressive stress trajectories, showing NE-SW direction in
Sorondo Range sector and NW-SE in Mitre Peninsula area. Since the late Miocene, left-lateral activity
along the Magallanes-Fagnano Fault System produced local deviations of the NE-SW compressive stress
toward an E-W direction. The present-day stress field is also characterized by NE-SW subhorizontal P axis
derived from earthquake focal mechanisms and geodetic studies.