根据沉积岩混合作用判别原理 ,应用元素铬 -钍判别法 ,判明川北砂岩 -泥岩系为二元混合成因。再根据二元混合元素丰度关系定律 ,由混合变换式求出丰度关系常数 ,认为川北砂岩 -泥岩系既具有互稀释混合作用 ,又具有稀释混合作用 ,进而可以对沉积岩端员物质组分进行估算 According to the discriminating principle of sedimentary rock mixing function, elemental chromium-thorium discriminant method is used to determine that the sandstone-mudstone series in North Sichuan is binary mixed. According to the law of the abundance of binary mixed elements, the abundance relational constants are obtained from the mixed transformation. It is considered that the sandstone-mudstone in the north of Sichuan has both dilute-dilution mixing and dilution-mixing effects, Estimate