Tropical Climatic Variation on the Pacific Slopes of the Ecuadorian Andes Based on a 25,000-Year Pollen Record from Deep-Sea Sediment Core Tri 163-31B

Abstract

Marine sediments from 3°37′S, 83°58′W yield a well-dated pollen record of equatorial Andean vegetation. Moderate development of Podocarpus -high montane rainforest (∼34,000-28,000 yr B.P.) and increase of high Andean grassland pollen (∼28,000-16,000 yr B.P.) imply an extended dry, cool glacial period following a brief interstade. Rapid stepwise expansion in coastal and montane forest pollen characterizes the deglacial interval. The general correspondence between pollen and oxygen isotope variations in Tri 163-31B suggests that tropical climatic variations in the northern Andes were basically coherent with northern hemisphere glacier variations.