The origin of the nodular limestone of Daye Formation of Lower Triassic in the Middle Yangtze region is studied on the basis of their petrologic characterishcs,chemical and isotopic compositions.

• 本文从基本特征出发，结合岩石学特征，尤其是化学成分及同位素组成等特征，对中扬子地区下三叠统大冶组瘤状灰岩的成因进行了探讨。