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

PATRICIO PAYROLA; FERNANDO HONGN; ERNESTO CRISTALLINI; VICTOR GARCÍA; CECILIA DEL PAPA

JOURNAL OF STRUCTURAL GEOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2012 vol. 42 p. 194 - 211

0191-8141

The dominant Cenozoic structural grain in northwestern Argentina trends north-south. However,several oblique folds have been mapped, mainly in the Cordillera Oriental and the Sistema deSanta Bárbara. Two oblique NE-SW-trending anticlines are well exposed in the LuracataoValley-Salta, along the western border of the Cordillera Oriental. These oblique anticlines aredefined by the Palaeogene Santa Bárbara Subgroup and are cut by the reverse faults boundingthe Luracatao Valley. We constructed analogue models to simulate the generation of obliqueNE-SW anticlines inside the narrow, trough-like Luracatao Valley. Orthogonal compression andbasement oblique heterogeneities, oblique compression and basement oblique heterogeneities,and oblique compression configurations were tested in the models. The first two configurationssimulate the anticline formation well. In addition, we analyse dextral rotation and the influence ofNeoproterozoic basement/Cretaceous rift structures as the cause of the oblique orientation. Theanalogue models suggest pre-Andean oblique structures controlling the oblique orientation ofthese Andean folds despite being a second-order planes of weakness