PRELIMINARY INVESTIGATION ON WEATHERING PROCESS AND VERTICAL ZONING CHARACTERISTICS OF CLINOSOL IN TIANSHAN MOUNTAINS

The Tianshan Mountain Range in Xinjiang has a large elevation difference,and its vertical zoning is significantly affected by climatic and topographic conditions. The unique geographical location and tectonic characteristics of the Tianshan Mountain Range determine the complexity of vegetation characteristics and vertical band spectrum development of the mountain range,which are the primary conditions affecting the distribution and development of clinosol. This paper summarizes the overall spatial-geographic pattern,geological mountain building process and special geomorphological development characteristics of the Tianshan Mountains in Xinjiang,and then clarifies the weathering-formation process and evolution mechanism of clinosol,and analyzes the boundary of vertical zoning in the Tianshan Mountains and the distribution characteristics of surface vegetation and geological hazards of clinosol in each zoning. The study shows that:(1)The Tianshan Mountains in Xinjiang cross the central part of Xinjiang,and the development of the mountains is mainly influenced by the Paleozoic land margin accretion-collisional orogeny,late Cenozoic intra-land orogeny and continuous glacial erosion,etc. Its unique climatic and environmental conditions are different and regular,which has created the features of complete horizontal transition and significant vertical divergence in the development of the Tianshan Mountains. (2)The weathering process of the clinosol in the Tianshan Mountains is characterized by in situ weathering,transport deposition and organic matter accumulation,each of which occurs sequentially and simultaneously,with a cyclic progression. (3)The vertical zoning of clinosol types according to the altitude gradient and hydrothermal conditions is mainly manifested as follows: the types of clinosol in the north of the Tianshan Mountains represented by Bogda Peak are,in order from high to low altitude,alpine primitive soil,alpine-subalpine meadow soil,mountain chernozem,chestnut soil,gray-brown soil and gray-brown desert soil. The types of clinosol in the south of the Tianshan Mountains represented by Tomur Peak are,in order from high to low altitude,alpine primitive soil,alpine-subalpine meadow soil,light chestnut soil,brown calcium soil and brown desert soil. (4)The geological hazards of clinosol in the Tianshan Mountains are influenced by geomorphological conditions and climatic environmental factors at different altitudes and have vertical zoning characteristics,which can be divided into glacier power type,ice and water erosion type,and strong precipitation recharge type. The study provides basic guidance for the clarification of vertical zoning and geohazard characteristics of the clinosol in different elevations.