关键词: 北京, 尘暴, 非尘暴, 大气花粉, 古土壤, 草本植物, 木本植物

Abstract:

Pollen assemblage characteristics which have been used to reconstruct paleoenvironment are taken as an important agent based on modern climate conditions for plants growth.It is particularly so in the loess research.Nevertheless,there are still some problems in deducing paleoclimate by the pollen assemblage discovered in paleosols,which were supposed to have developed under relatively warm and wet climate conditions,thus containing more pollens of trees than of herbs,but it is reverse actually.The best way to probe into such a question period is to observe the process of pedogenesis which was presumed to happen in the interglacial period with the similar climate conditions of today.What happened on the soil surface today might be the same as that in the interglacial period.Therefore this research takes air pollen samples in Beijing under different weather conditions of duststorms and non-duststorms in spring to discuss the pollen assemblage characteristics.The results show that both samples derived from duststorms and non-duststorms contain pollens of trees and herbs,in the majority of trees,representing modern sedimentary environment.Samples of duststorms contain more herbs pollens than samples of non-duststorms,which is argued by the authors to be transported from the source and pathway of storms.Further on,based on the analyses of the amount of dustfall annually,this paper concludes that more pollens of herbs have been transported and deposited under duststorm weather conditions than pollens of trees under non-duststorm weather conditions,which possibly is partial reason for the presence of pollens assemblage in paleosols.Though limit to the samples number this paper's view needs more proof,a new thoughtway on pollen research of eolian sediments still has been put forward.

Key words: pollen, Beijing, duststorms and non-duststorms, trees, herbs