LATE CENOZOIC VEGETATIONAL HISTORY AND THE PLIOCENE-PLEISTOCENE BOUNDARY IN THE YUSHE BASIN, SE SHANXI, CHINA

A continental stratigraphy column covering the Pliocene and Early Plei stocene in SE Shanxi, China has been studied using pollen analysis. te n pollen zones are defined with their correlation to magnetic polarity and Be-10 datings. The vegetational development and climatic changes during the period from 5.1 Ma to 1.8 Ma BP are discussed. Picea became a dominant component of the pollen assemblage in the Early Pliocene. Subtropical components such as Carya and Liquidambar occur in the Plio cene pollen spectra. The palaeoclimate of the Pliocene was moist and r elatively warm, though a trend towards a colder and drier climate is r eflected. Around 2.3 Ma BP the prevailing forest turned into a type of steppe and the subtropical components basically migrated out of the a rea. The Pliocene-Pleistocene boundary is also discussed using palynos tratigraphy. It seems reasonable to place the Pliocene-Pleistocene bou ndary close to the Gauss-matuyama magnetic boundary.