Millennial-scale climate variability in northwest Patagonia over the last 15 000 yr

Abstract

A pollen record from Lago Condorito (41 °45′S, 73 °07′W) shows prominent vegetation and climate changes at millennial time-scales, superimposed on multimillennial trends in temperature and westerly activity in northwest Patagonia during the past 15 000 yr. The record shows that evergreen temperate rainforests have dominated the landscape over this interval, with floristic changes ranging from cold-resistant North Patagonian forests with podocarp conifers to Valdivian forests with thermophilous, summer-drought resistant species. The long-term trend shows that cool-temperate and humid conditions prevailed between 15 000 and 11 000 cal. yr BP, followed by an extreme warm and dry phase between 11 000 and 7600 cal. yr BP, and subsequent cooling events and increase in precipitation that peaked at ca. 5000 cal. yr BP, when Southern Hemisphere alpine glaciers achieved their first Neoglacial maximum. Modern conditions were established at ca. 1800 cal. yr BP, following a warm and dry phase betwe