THE MINERAL COMPOSITION OF SOIL IN MIAOER MOUNTAIN

Miaoer mountain,the altitude of which is 2142 meters,is covered with dense vegetation due to abundant annual rainfall.The soils in that mountain developed mainly from granite and partly from arenaceous shale,phyllite and slate in some areas.The genetic process of soil in Miaoer mountain gets weaker with increase in altitude.The vertical sequence of soils from the mountain foot to the summit is in the order of mountain red earth,mountain yellow earth,mountain yellow-brown earth and mountain shrubby meadow soil.Corresponding to the vertical sequence ofthe soils,the quantity of 2:1 type mineral increases and that of kaolinite decreases gradually.Halloysite and gibbsite exist in all soil profiles and the latter tends to increase with the increase of depth.14A intergradient mineral is found mainly in the soils at about a little below the middle of the mountain where a mixed layer of mineral commonly occurs.The weathering index of the primary mineral in the soil developed from granite gets less with the increase in altitude.The conditions for the transformation of gibbsite are dealt with in this paper,and the relation among soil allitization,soil weathering and red earthening is also presented.