Origin and Evolution of the Salinas Grandes and Salina de Ambargasta, Argentina

Abstract

The Salinas Grandes and Salina de Ambargasta, on the eastern side of the Sierras Pampeanas in Argentina, constitute an 18,000 km2 tectonic depression. The eastward advance of the tectonic deformation is evident in the topographic elevations that intercept the Llanura Chaquea. The interpretation of the tectonic processes that create the Salinas Grandes and Salina de Ambargasta are primarily due to the observation of morphotectonic macro indicators and structural field data. These geoforms allow us to interpret the horizontal deformation that has produced the right side displacement of parallel shears within a dextral releasing bend and restraining bend setting. This process occurred within a transtensional-transpressional setting, which produced a depression closure where lakes formed, the formation of Alto de Mancilla, deviation of rivers, the rotation and displacement of ranges and the transformation of lakes into salt flats. These processes are active and are shown by the hydro transference area where the Dulce River discharges into the Salado River, resulting in a considerable decrease of water flow into the Laguna Mar Chiquita.