A 50,000-yr Pollen Record from Chile of South American Millennial-Scale Climate Instability during the Last Glaciation

Author： Heusser L. Heusser C. Kleczkowski A. Crowhurst S.

ISSN： 0033-5894

Source： Quaternary Research, Vol.52, Iss.2, 1999-09, pp. : 154-158

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Abstract

High-resolution (∼≤100 yr sampling interval) Chilean pollen data between ∼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 δ¹⁸O 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.