Late-glacial cooling in Amazonia inferred from pollen at Lagoa do Caco, northern Brazil

New pollen data from a core at Lagoa do Caco, Maranhao state, Brazil (2 deg rees 58'S 43 degrees 25'W; 120 m elevation), show higher frequencies of Pod ocarpus at the end of the Pleistocene than today. The increase in Podocarpu s, which follows the successive increase of various pioneer species such as Didymopanax, Melastomataceae/Combretaceae, and Cecropia, implies a progres sive late-glacial increase of moist and cool climatic conditions. A compara ble increase in Podocarpus is found in other lowland records in Amazonia. A review of published pollen data from Amazonia suggests that the moisture s ource was from the southeast. By contrast, present-day moisture comes from the tropical Atlantic and from the Amazon basin, with its convective precip itation. The likely cause for the southeastern moisture source between ca. 15,000 and 14,500 cal yr B.P. was enhanced polar (Antarctic) advection that reached low latitudes and maintained year-round the meteorological equator in its austral-winter position at northern latitudes or reduced drasticall y its southward summer displacement. This hypothesis is consistent with mar ine and ice core records. (C) 2001 University of Washington.