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Two >25,000-yr palynological records from central Brazil (Vereda de Aguas Emendadas, 15 degrees 34’s, 47 degrees 35’W, and Crominia, 17 degrees 17’s, 49 degrees 25’W) start with abundant pollen, spores and algae from cerrado and forest vegetation. A relatively humid and warm climate occurred from >32.4 to ca. 32 ka B.P., and was followed by a very cold and humid climate between 30 and 26 ka B.P. This humid phase was followed by a phase drier than at present between ca. 19 and ca. 7 ka B.P. During that long time there was desertification on the summit of Aguas Emendadas plateau and the disappearance of the palm swamp in Crominia. After 7 ka B.P., swamp and marsh vegetation started slowly to grow in the sites, indicating humidity was increasing. However, only after ca. 5 ka B.P. did savanna and wet soil vegetations reach the present values. Geological and geomorphological studies from other sites in tropical Brazil support the interpretation of this dry event. A 6200-yr palynological record from the sediments of Lagoa Santa (19 degrees 38’s, 43 degrees 54’W) shows that the lake started to form at ca. 4.6 ka B.P. after a period of torrential rainfalls. Palynological indication of dryness in South American savannas during the end of the Pleistocene/beginning of the Holocene was also found by other authors. However, records from rain forest areas and the Gran Sabana do not show a marked decrease in moisture suggesting the dry climatic event of Lake Valencia and central Brazil is perhaps limited to ’cerrado’ areas and plateau summits in lowland regions. These records suggest that the present savanna areas were under severe water stress from ca. 19 to 6-5 ka B.P., and that this event is independent of the glacial meltwater made available by the global water circulation during deglaciation. (C) 1998 Elsevier Science B.V.