Cold climatic episode of Younger Dryas age in Tierra del Fuego

Abstract

Pronounced climatic change during the last glacial maximum is recognized as global in extent, and has been attributed to orbital forcing¹. Not readily explained in a global context because of the equivocal nature of the evidence are the late-glacial climatic events of short (100–1,000-yr) duration. The cold climate of the Younger Dryas chron (∼11,000–10,000 yr BP), for example, is known to have been particularly pronounced over the North Atlantic and parts of Europe and North America^2,3, whereas in the Southern Hemisphere, cold conditions for that time are not well established. Here we present evidence for late-glacial climatic cooling in southernmost South America from studies of radiocarbon-dated glacial and pollen stratigraphy at sites along the Beagle Channel in Tierra del Fuego, where a forest–tundra tension zone in the region is especially sensitive to shifting climate. We conclude that the cold episode corresponds with the time of the Younger Dryas in Europe, when a drop in temperature, ascribed most recently to colder sea surface temperatures and production rate of deep water in the North Atlantic^4,5, apparently occurred worldwide.