INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
Permo-Triassic oblique extension along an ancient lithospheric anisotropy
L. GIAMBIAGI Y A. MARTINEZ
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
Año: 2008 vol. 26 p. 252 - 252
The Permo-Triassic evolution of southwestern South America was characterized by the development of a great amount of volcanism under extensional conditions. Structural analyses of faults developed coetaneously with this volcanism in the key area of Potrerillos-Uspallata, suggest the existence of an oblique-extensional setting primary controlled by the presence of a pre-existing lithospheric anisotropy. A clear parallelism between the trace of an inferred Devonian suture zone, the Late Paleozoic San Rafael orogenic belt, and the Permo-Triassic rifting, suggests that Early and Late Paleozoic tectonic inheritance permitted the reactivation of a NNW-trending long-live lithospheric weakness zone. The reactivation of this pre-existing weakness zone during Late Permian to Early Triassic time has resulted in the generation of a new complex fault system, which concentrated the oblique-slip normal displacement related to a NNE-SSW stretching (N23ºE).