黄土样品重量对孢粉分析结果的影响

Effects of Weight to the Pollen Analysis Results in the Loess Samples

黄土地层中,下层由于年代更老,经历更长时间的腐蚀,因此要比上层孢粉损失量更大,如何在下层黄土中提取到足够量的花粉并且保证孢粉分析结果的稳定性成为研究的重点.本文通过对黄土高原第四层黄土和第四层古土壤使用重液浮选法进行前处理,以样品重量为变量进行对比实验,应用相关性、多样性和相似性分析方法对孢粉分析结果进行研究,尝试找到最适实验样品重量.结果显示,当样品重量为200 g和250 g时,孢粉质量浓度趋于平稳,误差较小,这一重量区间的结果可信度更高.而物种多样性随样品重量变化的关系不明显,有待进一步实验研究.从鉴定结果的植被组成以及所占百分比含量这方面来看,当样品重量为150 g和200 g时,实验结果更加稳定.总的来说,样品重量在150 g^200 g这一区间时,各项孢粉分析结果更稳定、误差更小.

In loess strata,the lower loss more pollen than upper,how to extract a sufficient amount of pollen in the underlying loess and ensure the stability of the pollen analysis results is a focus of research.In this paper,sampling in paleosol period of S4 and loss period of L4 and dealing with the samples with Heavy liquid flotation process.Comparative experiments was conducted between four different sample weights,study the pollen analysis results by using relativity,diversity and similarity analysis method,try to find the optimum experimental sample weight.The results showed that when the sample weight of 200 g and 250 g,pollen concentration is more steady,the error is small,the results of this weight range is higher reliable.The relationship between species diversity along with the sample weight is not obvious,needs more study in future.In respects of vegetation composition and the percentage content of the identification results,when the sample weight of 150 g and 200 g,results of this experiment are more stable.Overall,when the sample weight is at the range of 150g-200 g,the pollen analysis results are more stable and less error.