Andean oblique folds in the Cordillera Oriental - Northwestern Argentina: Insights from analogue models

PAYROLA BOSIO, P; FERNANDO HONGN; ERNESTO CRISTALLINI; VICTOR GARCÍA; CECILIA DEL PAPA

JOURNAL OF STRUCTURAL GEOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2012

0191-8141

The dominant Cenozoic structural grain in northwestern Argentina trends northesouth. However,several oblique folds have been mapped, mainly in the Cordillera Oriental and the Sistema de SantaBárbara. Two oblique NEeSW-trending anticlines are well exposed in the Luracatao Valley-Salta, alongthe western border of the Cordillera Oriental. These oblique anticlines are defined by the PalaeogeneSanta Bárbara Subgroup and are cut by the reverse faults bounding the Luracatao Valley. We constructedanalogue models to simulate the generation of oblique NEeSW anticlines inside the narrow, trough-likeLuracatao Valley. Orthogonal compression and basement oblique heterogeneities, oblique compressionand basement oblique heterogeneities, and oblique compression configurations were tested in themodels. The first two configurations simulate the anticline formation well. In addition, we analysedextral rotation and the influence of Neoproterozoic basement/Cretaceous rift structures as the cause ofthe oblique orientation. The analogue models suggest pre-Andean oblique structures controlling theoblique orientation of these Andean folds despite being a second-order planes of weakness.