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伊利石是我国黄土和古土壤中最主要的粘土矿物。本文选择陕西洛川黄土-古土壤国际典型剖面为研究对象,通过测定伊利石的结晶度(Kubler指数)、Srodon峰强比值(Ir)和2M_1多型含量,发现黄土物质的起源与中高温(>280℃)地质环境有关;黄土样品中伊利石结晶度值为0.25°2θ(Cu Ka),古土壤样品中伊利石结晶度值大于0.27°2θ(Cu Ka);黄土和古土壤中伊利石结晶度值的差别,是由于古土壤中伊利石含少量的膨胀层,而黄土样品中的伊利石不含有膨胀层而引起的。古土壤中伊利石的膨胀层的成因,与伊利石在温湿的气候环境下发生退变有关。伊利石的结晶度值和Ir值可作为研究古气候环境变化的定量指标。
Illite is the most important clay mineral in China’s loess and paleosol. In this paper, we selected the typical sections of loess-paleosol in Luochuan, Shaanxi Province as the research object. Through the determination of the Kubler index, Srodon peak-intensity ratio (Ir) and 2M_1 polytype content, > 280 ℃). The values of illite in the loess samples were 0.25 ° 2θ (Cu Ka), the values of illite in ancient soil samples were larger than 0.27 ° 2θ (Cu Ka) The differences in crystallinity values are due to the fact that the illite in ancient soils contains a small amount of intumescent layers and the illite in the loess samples does not contain intumescent layers. The origin of illite expansion in ancient soils is related to the degeneration of illite under warm and humid climatic conditions. The crystallinity value and Ir value of illite can be used as a quantitative index to study the changes of paleoclimate environment.