酒泉盆地火烧沟组孢粉记录及其意义

hrough the analysis on the redrock pollen from the Huoshaogou Formation in the northern margin of the Tibetan Plateau, northwest China. The result shows that there are the arid-semiarid palynofloras during the 40.2~33.4 Ma in the middle to late Eocene, the main types are Nitrariadites and Chenopodipollis, Ephedripites as well as a small quantity of north tropical types, including Rutaceoipollis, Rhoipites, Meliaceoidits, Fraxinoipollenties, Cupuliferoi - pollenties, Euphorbiacites and Magnolipollis etc. The total palaeoclimate indicated by the characteristic of the pollen record is subtropical Savanna and the detailed palaeoclimtic fluctuation can be well compared with the global climatic change. At the same time, combining with the pollen data from the Qaidamu Basin as well as from other basins in northwest China at that time, based on the newest age data and the biostratigraphic correlation , the results tell there is one good palynofloras with very closed relationship among those palynofloras from the different basins in northwest China, which is named Ephedripites~Nitrariadites~ Chenopodipollis pollen zone from the Qaidamu Basin, and we think there is a broad and in lower attitude region in northwest China controlled by the arid-semiarid Savanna climatic environment.