Analyses of REEs from the Ediacaran—Cambrian transition interval black rock series on Nangao section and Zhalagou section, eastern Guizhou, South China, cha racterized by: (1) lots of REEs enriched at the boundary between the Meishucunia n and Qiongzhusian; (2) a distinct negative Ce anomaly and a positive Eu anomaly , indicate anoxic conditions with hydrothermal inputs. However, oxygendeficient environment and hydrothermal inputs varied between the sections. The black shal e of the Niutitang Formation in Danzhai was deposited in an oxygendeficient env ironment gradually transforming to an oxic environment in the shallow she lf area, with occasional upwelling and hydrothermal fluid input. The black chert of the underlying Laobao Formation formed in an oxic environment between the sh elf and slope. In contrast, the silicastone of the Laobao Formation in Sandu for med in an anoxic environment in deeper water with frequent hydrothermal activity , as in western Hunan and the Tarim Basin.