Pollen analysis of ODP Hole 202-1239A

Vegetation and climate change in western equatorial South America were studied using palynological analysis. We studied 88 marine sediment samples from ODP Site 1239 dated between 3.9 and 2.7 Ma. The presented pollen record represents the regional vegetation from the coastal lowlands to the high montane Páramo in the western Andean Cordillera. A trend towards more open vegetation is observed. The climate changes towards cooler conditions, which is manifested by a lowering of the forest line from 3.3 Ma on. An increase of Amaranthaceae pollen after 3.1 Ma suggests drier conditions along the coast. The isochronous occurrence of environmental changes in the presented record, that is, cooling and coastal drying, with the first major pulse of ice‐rafted debris and cooling temperatures in the Northern Hemisphere suggests that these changes might have been a precursor of the intensification of the Northern Hemisphere glaciation.