二叠系区域性盖层中沥青的稀土元素特征和配分模式与寒武系沥青相同,而与志留系烃源岩显著不同,说明区域性盖层中的沥青来自于下伏寒武系牛蹄塘组烃源岩。
The REE characteristics and distribution model of pitch in Permian regional superimposition bed are as same as those of Cambrian,but they are evidently different from those of Silurian,which indicates that the pitch in regional superimposition bed originates from the underlying Cambrian Niutitang Formation hydroxyl origin rock.