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Keywords:

  • Beijing;
  • Early Pleistocene;
  • fluviolacustrine sediments;
  • Mid-Pleistocene Transition;
  • pollen

ABSTRACT

To reconstruct the history of climate and environment in East Asia during the Early Pleistocene, a palynofloral investigation was conducted on fluviolacustrine sediments in Beijing, North China. The results indicate that herb and shrub taxa were dominant in most of the samples, reflecting an open forest grassland covering the Beijing region during much of the Early Pleistocene. This vegetation generally declined during 1.68–1.25 Ma and recovered in part during 1.25–0.96 Ma. From 0.96 Ma, conifers gradually replaced broad-leaved trees, shrubs and herbs. After 0.65 Ma, the pollen abundance of conifers, shrubs and herbs all increased significantly. These vegetation changes took place in the context of long-term global cooling during the Late Cenozoic. A significant increase in Antarctic ice volume at 1.25–1.20 Ma and the resultant increased meridional temperature gradient in the Southern Ocean led to prominent anomalous warming in the tropics and increased heat/moisture flow across the Equator, probably resulting in vegetation recovery in the study area to some extent during 1.25–0.96 Ma. From 0.96 Ma, the stepwise decline of vegetation cover in the study area, especially after 0.65 Ma, was driven by further development of global cooling and increase in polar ice volume.