Volcanicity was violent during the Early Carboniferous in Santanghu region.The volcanic rocks consist of basalts,andesites and dacite liparite,with andesites playing the main part.

三塘湖地区早石炭世火山活动强烈，发育以安山岩类为主的玄武岩、安山岩、英安流纹岩的岩石组合。