The results show that hard-dres s ing mineral matters within coal are original, chemical, biochemistry and regiona l under the control of depositional setting.

• 受沉积环境的制约，难选矿物质具有区域性，除难选硫之外，西南晚二叠世煤中的难选矿物质主要是石英，华北石炭二叠纪煤中的难选矿物质主要是高岭石和伊利石；