INTEGRATIVE METHOD OF SIEVING AND HEAVY LIQUID IN POLLEN ANALYSIS OF LOESS—Data Analysis and Processing

Abstract

High-resolution pollen study of loess can reconstruct the vegetation history in loess plateau and discuss the vegetation characteristics of terrain and non-terrain in different episode.In the meantime,high-resolution pollen records play an important role in further studying on the rule of vegetation variation and palaeoecological pattern,understanding the control factors and dynamic mechanism of monsoon variation,providing the information of human activity and its impaction to environment in loess plateau. The Integrative method of sieving and heavy liquid provides a new approach for the studying on the analysis of loess pollen.The method is also applied to the samples of culture layer,soil and the lake sediment.The sieving analysis machine is used to take out the fine particles with sieve(the aperture10 μm).In this process,not only is about 30% weight of sample removed,but also the porosity of sample is increased,the viscosity and adsorption of clay are reduced. On the other hand,two kinds of heavy liquid are used in two different steps for the purpose of increasing the rate of pollen extraction and decreasing the costing of expensive chemical reagent.The pollen results of 19 samples from Fufeng section show that a total of 41 pollen taxa including Abies(the biggest grain size) and castanea(the smallest grain size) are obtained,which cover the main pollen types of loess plateau.The method helps us to get over 300 pollen grains only counting 2-3 slides. Comparing with the conventional method of pollen analysis,the advantages of sieving-heavy liquid method are as follows:(1) Little pollen is loss and more pollen types.(2) Less destroying to the pollen structure and lines.(3) Shorter process.A whole process of 8 samples only needs 4 days.(4) Not using the toxicity reagent for the safety of the analysis process.