(4) During the deposition of the Benxi Formation of Carboniferous, four cycles of relative sea level changes could be identified based on the study of sedimentary facies and community palaeoecology.

• 底栖生物群落生态位变化和剖面沉积相分析所揭示的海水深度的垂向变化规律，显示该区石炭纪本溪期经历了4次明显的三级相对海平面变化旋回。