Evidence of Late Cenozoic Contractional and Strike-Slip Deformation in the Transition Between Puna and Frontal Cordillera in Valle Ancho Area (27°30’S) (Spanish Presentation)

Authors: Fabian Wagner (presenter), Universidad Mayor (Chile); Rodrigo Quiroga, Grupo Tectónica, IANIGLA, CCT Mendoza (Argentina); Matías Peña, Universidad Mayor, Universidad de Chile; Guillermo Fuentes, Universidad Santo Tomas (Chile)

Presentation is in Spanish

The southern area of Central Andes (27°30´S), in the southern limit of Puna, in transition to the Frontal Cordillera, exist a high structural complexity characterized by fold and thrust belt system with interaction of thick and thin skin styles of deformation, evidenced by Paleozoic basement highly exposed, and Oligocene Miocene-Pliocene continental-volcanic-and-clastic sequences, which degree of deformation and temporality of deformation is not well understood. This suggest that is necessary to analyses the history of deformation during the late Andean evolution in this area. To accomplish this goal, we perform a structural and kinematic analysis, integrated in a structural model using Leapfrog and Andino 3D. This structural study is a contribution in the knowledge in the temporal-space variation of the strain field and its relationship with main deformation events.

We propose two deformational events. The first, an early contractional event whose contraction directions varies from E-W to NE-SW near to Permian basement blocks, whose structural architecture is controlling the NW-SE and E-NE strike slips faults generated on the second event and the orientation of folds and faults developed during the first one. A Strike-Slip deformation is observed by faults that cut Miocene-Pliocene volcanic units and the previous contractional system. Because the reverses faults and folds are affecting the Oligocene Miocene rocks, the early contractional event documented in our kinematic analysis was active at least until the lower to mid Miocene times. The late deformational event is represented by the strike slip deformation that was active until recent times, defining in this way the temporality of deformation in Frontal Cordillera, in the transition with the Puna Plateau.

Bio

Fabian Wagner (presenter), Universidad Mayor (Chile)

Fabian is a last year student at the Universidad Mayor, Chile. He currently works as researcher at the same university.