A 50,000-yr pollen record from Chile of South American millennial-scale climate instability during the last glaciation

High-resolution (similar to less than or equal to 100 yr sampling interval) Chilean pollen data between similar to 10,000 and 60,000 cal yr B.P. exhib it systematic fluctuations in Subantarctic Parkland development. These vari ations are dominated by a 30,000-40,000-yr cycle similar to that in the Nor thern Hemisphere GISP2 delta(18)O data and other climatic records. Both Chi lean and GISP2 data show oscillations in the 5000-12,000 and 1000-3000-yr p eriod bands. The coherence is, however, generally low, and distribution of power spectra differs, with the dynamics of the pollen assemblage dominated by a combination of 12,000- and 5000-yr cycles. We suggest a preferential nonlinear response of Chilean vegetation to climatic forcing and interhemis pheric differences as possible mechanisms underlying the resemblances and d issimilarities between both records. (C) 1999 University of Washington.