Geochemical characteristics of paleo-weathering crust of Permianbasalt in northwestern Guizhou
GUO Peipei1, 2, ZHANG Hai1, LIU Jun1, SANG Shihua2, LI Yuanyuan1, YANG Dechuang1, HUANG Taizhong1
1.NO.113 Geological Brigade of Guizhou Bureau of Geology and Mineral Resources, Liupanshui 553001, China; 2.The College of Nudear Technology and Automatic Engineer Chengdu University of Technology, Chengdu 610059, China
Abstract：Through the field investigation, sampling and test of basalt paleo-weathering crust in Emei Mountain, this paper has the following conclusions:(1) Emei basalt is widely outcropped in western Guizhou. The ancient climate of Late Permian is warm and wet, so it is helpful for the formation of paleo-weathering crust containing clay minerals of iron, titanium and aluminum. This weathering crust is controlled by the paleogeographic environment and the Emei basalt. (2) Compared to basalt, major elements in aluminum clay is characterized by rich TiO2, Al2O3, mild loss of SiO2, obvious loss of TFe and other main elements shows a great loss. And major elements in iron clay is characterized by rich TFe, TiO2, mild rich Al2O3. But compared to the aluminum clay, the TiO2 concentration is low, and SiO2 and other elements shows an obvious loss.(3)Due to frequent transgression of Late Permian, the lower part of paleo-weathering crust in areas with higher ground water levels, is in the reduction conditions. Fe is restored in soluble bivalent state or gets out of paleo-weathering crust under the effect of organic matter. Due to a stable state, Ti continues to save in clay minerals and is differentiated from Fe. Clay minerals and iron are sorted to form the differentiation of Fe and Al, Ti due to the density difference under the gravity differentiation in oxidation environment of local shallow water, along with the enrichment of titanium ore, iron ore and bauxite. The discovery of the enrichment regularity is of theoretical guiding significance to the exploration of the iron, titanium and aluminum ore.
2017, Vol. 4 
