A ∼6100 14C yr record of El Nino activity from the Galapagos Islands

Lithostratigrahic and mineralogic analyses of sediments from hypersaline Bainbridge Crater Lake, Galapagos Islands, provide evidence of past El Nino frequency and intensity. Laminated sediments indicate that at least 435 moderate to very strong El Nino events have occurred since 6100 C-14 yr BP (similar to7130 cal yr BP), and that frequency and intensity of events increased at about 3000 C-14 yr BP (similar to3100 cal yr BP). El Nino activity was present between 6100 and 4000 C-14 yr BP (similar to4600 cal yr BP) but infrequent. The Bainbridge record indicates that there has been considerable millennial-scale variability in El Nino since the mid-Holocene.