The Geochemical Characteristics Of Typical Weathering Profiles In The Region Of Guizhou Plateau

Guizhou Plateau is located in the east of the Yunnan-Guizhou Plateau, karst landscape is widely distributed and full with varieties of landscape in Guizhou Plateau. Typical silicate weathering profile and carbonate weathering profile in the karst areas of Guizhou Plateau are selected as the main studying objects, based on the study of the element distribution and the chemical weathering intensity, we draw the following conclusions:The content of SiO2、Fe2O3、Al2O3are the highest in the compositions of the major elements of the two profiles, but the distribution of the major elements are significantly different, which is owing to the different parent materials. There are significant differences between the values of the chemical index of alteration(CIA) of the two profiles, which illustrates that the stages of chemical weathering are different, the weathering of Deng Jiawan profile is moderate while Pingba profile is very strong, and the intensity and trend of the weathering are significantly different. The differences of the parent materials and degree of chemical weathering can be judged out according to the values of Rb/Sr and CIA, which reflects that the different types of soils in one sampling area show variations in the chemical compositions. The strong weathering results in the abnormal enrichment of REEs in the two profiles, distribution patterns of REE are also significantly different, the formation of the profiles are due to the weathering of their own bedrock, there isn’t close contact with Chinese Loess.