CONICET | Buscador de Institutos y Recursos Humanos

The diachronous and spatially disparates characteristics of active broken foreland provinces constitutes one of the most enigmatic phenomena in tectonically active mountain belts. The seemingly unsystematic behavior of faulting and the lack of a clear active deformation front in broken forelands make these regions a difficult environment to evaluate the overall patterns of seismicity and deformation, thus complicating hazard and risk mitigation efforts. This may be complicated further, because seismic recurrence intervals in such regions are long and the seismic record in the landscape (deformed terraces, pediments, and fault scarps) may be modified or even obliterated by climatically driven surface processes.The Candelaria fault is a 20 km-long fresh thrust fault scarp with a N7°E strike located along the western flank of the Candelaria range (South portion of Salta province). Through this fault, which records cumulative minimum offsets on the order of several meters, rivers have formed trenches through the uplifted lower part of alluvial fans (Wayne, 2011).An analysis of the fluvial dynamics by means of knick point and ksn index, complement this idea and suggest an old Quaternary age for this structure.However, topographic profiles with differential GPS located in strategic sectors perpendicular to uphill-facing scarp and with determining the heights of the escarpment by the method of Walker et al. (2015), allowed us to identify great imbalance in the far-field slope according to fault-scarp parameters (Hanks and Andrews 1989), which increases drastically in the hanging wall fan slope close to the scarp and showing a folded surface, that is, an increase in vertical fault displacement with respect to local relief at scarp. Therefore, we consider that this landform geometry could answer to a Quaternary fold propagation model affecting the fan surface giving place to the hypothesis of a younger Quaternary deformation than supposed.Next research will focus on the age of the fan surface in order to know the maximum age of the deformation.