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

Around 30,000 C-14 yr BP, multiple landslides in the Quebrada de Cafayate (26 degreesS, 66 degreesW) dammed the Rio 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 degreesC drop in temperature would result in a stable lake level at the reconstructed elevation. This result implies wetter and cooler conditions at 30,000 C-14 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. (C) 2001 Elsevier Science B.V. All rights reserved.