Kinematic analysis of the mesozoic - Early Cenozoic deformation in the paipote basin (27°10′S)

Abstract

An integrated structural and kinematic study focused on the characterization of an Andean Mesozoic basin was carried out in the upper stream of the Paipote Creek, in the western limit of the Southern Puna, Fault slip data analysis (n = 80) and structural observations at different scales were collected from Triassic to Upper Cretaceous volcanic and sedimentary units to constrain the structural architecture and the kinematic evolution of the area. Regional observations provide evidence for syntectonic extensional deposition during the Triassic - Jurassic and positive tectonic inversion from at least the Late Jurassic. Extensional features such as growth strata, harpoon structures and roll-over anticlines, helped to infer two main depocenters controlled by west dipping listric faults. E-W extension directions have been recognized in Triassic - Jurassic units, linked to an extensional basin architecture, and mixed contraction directions were related to compressional and strike-slip deformation in the area. A forward model is proposed based on the interpreted architecture in depth of the basin, defining two major depocenters that, together, define the Paipote basin. A shortening estimate of 21% (5,44 km) was calculated for the basin, wich corresponds to the lowest shortening values reported for the Triassic-Jurassic basins in the Atacama region. The strike-slip deformation can be associated previously with recognized NW-SE strike-slip faults, and aids in proposing the Paipote basin as a transitional zone between the Lautaro basin to the south and the Potrerillos basin to the north.