Palynoflora at Late Miocene—Early Pliocene from Leijiahe of Lingtai,Gansu Province,China

Abstract

Vegetation and climate changes of Late Miocene_Early Pliocene have been deduced based on pollen research from Wenwanggou and Xiaoshigou sections near Leijiahe village (ca 35°04′15″ N,107°43′30″ E). The two sections are quite famous of rich micromammalian fossils. Before ca. 6.5 Ma, open forest_grassland was distributed in the studied area indicating a temperate and humid condition at that time. In the period between ca.6.5 and 5.8 Ma BP (Late Miocene) predominance of Chenopodiaceae and Artemisia implies that desert or desert_grassland was developed in the area and the climate should be cold and dry. During the time interval from ca.5.8 to 3.4 Ma BP mixed conifer and broad leaved deciduous forest with a few subtropical tree taxa had replaced the arid desert vegetation indicating a warm and humid climate. The climate aridity event of Late Miocene can be correlated with the global climatic event.