Abstract
New AMS radiocarbon data from the deposits of landslide-dammed lakes in the Santa Maria Basin (26°S, 66°W) and the Quebrada del Toro (25°S, 66°W) in the eastern Argentine Cordillera show that important mass movements occurred during a wet period between 40,000 and 25,000 yr B.P. In addition to increased humidity during this time, detailed analysis of annual-layered lacustrine strata suggests enhanced inter- and intra-annual fluctuations in precipitation as compared to the present. Variations in sediment characteristics and diatom assemblages with mean periodicities of 2 to 5 and 10 to 14 years, respectively, suggest an influence of the El Niño/Southern Oscillation (ENSO) and the Atlantic sea-surface temperature dipole. The Atlantic dipole slightly increased rainfall every 10–14 years as at present. In contrast, the weak modern ENSO influence in this area differs from the past situation where rainfall increased significantly with ENSO-type periodicities. Both increased humidity and seasonality are believed to have reduced thresholds for the generation of catastrophic mass movements in northwestern Argentina.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
