THE STRATIGRAPHIC RECORD FOR CLIMATE-CHAN GE AT THE END OF THE PLEISTOCENE IN SOUTHERN SOUTH-AMERICA

In the mid-latitudes of South America, glaciers reached their maximum extent at 19 000 year BP By 13 000 yr BP glaciers were in rapid retrea t from Tierra del Fuego to the Chilean Lake Region. The retreat may ha ve been initiated synchronously before 14 000 yr BP by sea level rise. Deglaciation along the Pacific coast proceeded more rapidly than alon g the eastern flank of the Andes. In the mid-latitudes, the glacial ve getation, a wet moorland, was replaced by rain forest between about 14 000 yr BP and 12 500 yr BP. The massive biotic response was caused by a rapid rise in mean summer temperature of about 4-5-degrees-C. In th e high-latitudes, the climatic response was different. Mean summer tem peratures and precipitation levels in Tierra del Fuego, Patagonia, and the South Atlantic were low until the early Holocene. The muted respo nse in the southernmost regions was possibly caused by the lengthy deg laciation of Antarctica. Evidence for the existence of a return to col d climatic conditions between 11 000 to 10 000 yr BP is conflicting. P resently, the weight of evidence is against there having been any sign ificant climatic change at the time of the Younger Dryas.