风成沉积物环境敏感粒度指标的提取及意义

采用SPSS11.5软件中的主成分分析方法,对黄土高原西部末次冰期沉积的宁夏中卫冰沟剖面和兰州沙金坪剖面的粒度进行了环境敏感粒度指标的提取,沙金坪剖面和冰沟剖面的环境敏感粒级分别为24.70-27.90μm、62.47-68.97μm,冰沟剖面的阈值基本是砂粒级标准(>63μm),冰沟剖面由于距沙漠源区更近,受物源影响更大而使敏感组分更粗,不同地区的环境敏感粒度指标存在差异。另外,不同数学方法提取的指标也存在差异,数学方法的运用必须考虑其数值所表示的物理机制和环境意义。

Analysis of Grain-size Populations With Environmentally Sensitive Components in Aeolian Deposits and Their Implications

Chinese loess-paleosol sequence has provided the most detailed terrestrial records of climate changes during the last glacial.The grain sizes of sediments during the last glacial in two sections of the west of Chinese Loess Plateau were systematically studied: Using SPSS of 11.5, principal component analyses showed the environmental sensitive grain-size populations were 24.70～27.90μm and 62.47～68.97μm in Shajinping and Binggou section respectively,suggesting different sediment implications.The sensitive grain-size populations of Binggou profile were coarser because they were more influenced by the distance of material resources.The environmental sensitive grain-size populations were quite distinct in different regions.The analysis of the two methods of standard deviation of each grain-size class and principal component analysis demonstrated dissimilar,which was deposited during the last glacial period,and suggested different physical mechanisms and environmental implications.