Send to

Choose Destination
Science. 1999 Jan 22;283(5401):516-20.

An approximately 15,000-year record of El Nino-driven alluviation in southwestern ecuador

Author information

D. T. Rodbell and J. H. Newman, Department of Geology, Union College, Schenectady, NY 12308-2311, USA. G. O. Seltzer, Department of Earth Sciences, Syracuse University, Syracuse, NY 13244-1070, USA. D. M. Anderson, National Oceanic and Atmospheric Adm.


Debris flows have deposited inorganic laminae in an alpine lake that is 75 kilometers east of the Pacific Ocean, in Ecuador. These storm-induced events were dated by radiocarbon, and the age of laminae that are less than 200 years old matches the historic record of El Nino events. From about 15,000 to about 7000 calendar years before the present, the periodicity of clastic deposition is greater than or equal to 15 years; thereafter, there is a progressive increase in frequency to periodicities of 2 to 8.5 years. This is the modern El Nino periodicity, which was established about 5000 calendar years before the present. This may reflect the onset of a steeper zonal sea surface temperature gradient, which was driven by enhanced trade winds.

Free full text

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center