The Analysis Method Based on Ash- Composition and Its Application in Coal- Accumulating Environment Reconstruction

Key words: 
• ash-composition /
• environment analysis /
• coal accumulation /
• Hedong Coal Basin

Abstract: The Analysis Method Based on Ash-Composition is a new method in coal-accumulating environment analysis and reconstruction. Principles of the method are that all ash composition comes from the minerals and clasts in coal seams, so it is possible to reversely infer the sorts, contents and grading law of the minerals and clasts of coal seam from the sorts, contents and grading law of ash composition,in advance to judge the coal forming environment. Main points are as follows: (1) According to the end-member SiO₂-Al₂O₃, analyze the sort, content and its grading law of clay minerals and land-source clasts in coal seams,in advance to judge the main direction of trasportion. (2) According to the end-member CaO-MgO, analyze the sort and content of calcium-magnesium mineral in coal, in advance to judge the distance between coal-accumulating environment and the marine. (3) According to the end-member Fe ₂O ₃-SO ₃, analyze the sort and content of iron mineral (esp. pyrite), in advance to judge the oxidation-reduction condition of coal-accumulating environment. This method was applied in studying accumulating environment of coal seam No.10# in Taiyuan Group, Hedong Coal Basin, and achieved satisfactory result,which proved that the analysis method based on ash-composition is a valuable way in reconstructing coal forming environment.