Hydrological modelling of a Pleistocene landslide-dammed lake in the Santa Maria Basin, NW Argentina

Around 30,000 14C yr BP, multiple landslides in the Quebrada de Cafayate (26°S, 66°W) dammed the Rı́o de las Conchas and caused a lake in the Santa Maria Basin, NW Argentina. Since climate could have played a major role in landslide generation, we used a lake-balance model to compare the present-day climate with the conditions during landsliding. This model reveals that a hypothetical present-day lake would stabilize around 70 m below the reconstructed paleolake level. The volume of the water body would be one third of the corresponding paleolake volume. However, a minimum 10–15% increase in mean-annual precipitation accompanied by at least a 3–4°C drop in temperature would result in a stable lake level at the reconstructed elevation. This result implies wetter and cooler conditions at 30,000 14C yr BP as compared to the present. Wetter climate in turn could help to explain enhanced landsliding in the Quebrada de Cafayate during this time.