QUARTERNARY DEFORMATION IN THE CALCHAQUI VALLEY, EASTERN CORDILLERA NW ARGENTINA

FIGUEROA VILLEGAS S.; ESCALANTE L.E.; HONGN FERNANDO; ARANDA VIANA, G

Heidelberg

Congreso; 24th Colloquium on Latin American Earth Sciences; 2017

Universität Heidelberg

In the Calchaquí Valley, several authors have contributed knowledge about neotectonic structures (Casa et al., 2014, Hongn et al., 2014, and others). Some of them focused only on the quaternary deformation, while others, only on the last stages of the Cenozoic evolution. Fieldwork in the area has contributed new data for neotectonic analysis improving the description of known structures and identification of new structures that reflect a more extensive and intense quaternary deformation than the one assumed for the region. Several morphological features such as faulted alluvial fans, anomalies in the drainage networks, rivers profiles in imbalances and knickpoints document the neotectonic activity in the study area. With respect to structural features, thrust folds and sintectonic sedimentation or folds clearly associated to intraquaternary discordance also document the neotectonic activity. The next stages of research are aimed to dating the quaternary events. For now, it is possible to conclude that the main faults respond to reactivations of paleogene-neogene structures with western vergence possibly inherited from the cretaceous rift, others related to interstate slips during the folding of the Salta Groups and Payogastilla. Further studies will allow to adjust the last stages of Andean evolution and to evaluate seismic risk in the Calchaquíes Valleys.