Field observation and laboratoy st udy show the ferroan dolomitesilicilith which ouurred at the bottom of the Middle Devonian Xingho-ngpu fomation is formed in submarine environment of the active rift.

• 野外和室内研究表明,产于凤太地区中泥盘统星红铺组地层底部铁白云石硅质岩,形成于活动性断裂的海底环境。