Geochemistry of clay parting in No.3 coal mine of Yangquan Coal Co. Ltd of Shanxi Province

The contents of the major and trace elements in 3 samples of the claystones from the coal measures of Taiyuan and Shanxi Formations of Permo-Carboniferous in No.3 coal mine of Yangquan Coal Co. Ltd of Shanxi province have been detected by chemical analysis and INAA respectively. By the contrast analysis to the elements with geochemical tracer and their ratio, the three samples, on geochemistry as a whole, are not of the typical characteristics of sedimentogenic mudstone, and could be formed in situ from the alteration of acidic or alkali-acidic ash (fallout or water-carried) under the conditions of the shallower water and weak oxidation on the surface. The alteration of the claystone is stronger on the whole, and it causes much loss of the unstable elements, even some of the more stable elements, such as ferromolybdenum and manganese. The strong alteration of the original matters, as well as the change of mineral composition in the rocks is the major reason to result in the differences between clay rocks, and clay rock and its original matter on the element contents and the REE patterns.