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. exhibit systematic fluctuations in Subantarctic Parkland development. These variations are dominated by a 30,000-40,000-yr cycle similar to that in the Northern Hemisphere GISP2 delta(18)O data and other climatic records. Both Chilean and GISP2 data show oscillations in the 5000-12,000 and 1000-3000-yr period 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 interhemispheric differences as possible mechanisms underlying the resemblances and dissimilarities between both records. (C) 1999 University of Washington.