Abstract:

 The chemical weathering intensity and element migration features of the Granite-type Laterite Profile in Tiancun, Gan xian are studied in this paper. The results indicate that: (1) The laterite is mainly composed of SiO2, Al2O3, Fe2O3, which account for over 90% of the total and the SiO2is the highest. The content of soluble constituents such as K2O, CaO, Na2O, MgO, are relatively lower. (2) Major element geochemistry behavior present the migration leaching during the process of weathering in the Granite-type Laterite Profile and the degree of migration is strengthened gradually from the bottom to the top. CaO, Na2O migration amount are 97.34%, 94.94% on average, respectively, and belong to the strong migration elements; MgO, K2O, SiO2 average migration quantity are 52.50%, 39.89% and 22.72%, respectively, belong to the easy transition element, the element characterized by high concentration was Fe. (3) We found the Granite-type Laterite Profile suffered strong chemical weathering in hot and humid environment in Gan xian and the weathering intensity became gradually weak form the top to the bottom, on the basis of the comprehensive analysis of the coefficient of aluminum and iron, chemical alteration and weathered eluvial.

Key words:  Granite-typeLateriteProfile;chemicalweatheringintensity;elementmigration;Tiancunsection