The EL abra stadial, a younger dryas equivalent in Colombia

Abstract

A survey of radiocarbon-dated palynological, stratigraphical and glacio-morphological evidence from Colombia is presented showing a cold climatic fluctuation most likely between 10,900 and 10,100 BP, immediately preceding the initiation of the Holocene. This fluctuation, called the El Abra stadial, is characterized by lower temperatures and less precipitation, and occurs after the Late-Glacial Guantiva interstadial. Average annual temperature during the Guantiva interstadial may have been 2°C lower than today, and during the El Abra stadial from 4° to 6°C lower than today. The upper forest line during the El Abra stadial was some 400 to 500 m lower than during the Guantiva interstadial and some 600 to 800 m lower than today. The Guantiva interstadial-El Abra stadial-early Holocene sequence is radiocarbon dated by some 45 dates and evidence is shown from 14 areas, mostly located at high elevations (2000–4000 m) in the Eastern and Central Cordillera and in the Sierra Nevada de Santa Marta, but some from the tropical low-lands. Although more precise dating of the boundaries is desirable, we interpret the Guantiva-El Abra climatic fluctuations as equivalents in time and climatic phenomena to the Allerød-Younger Dryas sequence in Europe.