Taton dune field: wind selection across the Southamerican arid diagonal, Puna Argentina

Fiambala is a tectonic valley emplaced in the southern Puna region, Catamarca Province, Argentina. At the Western side of the valley, “bajadas” and tuff deposits are interfingered.  Westerly winds cause an eastward sand transport, either by saltation or deflation. Sand is therefore accumulated eastwards, attached to the Fiambala Range. This sand ramp located close to the Taton village was surveyed in terms of its morphology and sand composition. The central section of the valley is occupied by the Abaucan River, which runs across the dune field. Three oases developed at these aggradation plains: Palo Blanco, Medanitos and Fiambala. These localities however have been threatened by desertification processes in the last years. Three profiles were described along the aggradation plain of this valley. The transversal and longitudinal dunes of Taton are composed of fine sand with 12-28% of volcanic ash, deposited within the last 5500 years. Grain-size selection was caused by aeolian transport processes. Dune ramps developed in areas dominated by sand transport while loess-sized material is deflated outside the valley.