ON AGE OF THE CHANGYANG FORMATION OF WESTERN HUBEI

Reinvestigation on the original section of the Changyang Formation reveals that the faults in the top of the section do not seriously affect the sequence of the Changyang Formation and there is no mis-recognition problem on the original recognized sequence of the Changyang Formation.The conodont analysis on the two samples from the original section and nearby area reveals that the Changyang Formation yields a typical Lower Carboniferous conodont assemblage characterised with abundant Siphonodella levis,some Polygnathus inornatus,P.cf.symmetricus,Bispathodus aculeatus,Pseudopolygnathus originalis,and absence of typical Devonian elements,such as Icriodus,strongly supporting that the Changyang Formation belongs to the Lower Carboniferous rather than the Upper Devonian.The conodonts and brachiopods support that the Changyang Formation can be correlated to the lower Tournaisian(or Yanguanian) formations of the neritic facies in South China,such as the lower member of the Tangbagou Formation in southern Guizhou,the major part of the Malanbian Formation(or the lower part of the Liujiatang Formation) in central Hunan, and the Yaoyunling Formation in northern Guangxi,as well as the upper part of the Leigutai Member of the Wutong Formation in Jiangsu and Anhui provinces.The overlying Jinling Formation can be correlated to the upper Tournaisian(or Yanguanian) formations,such as the upper member of the Tangbagou Formation in southern Guizhou,the top of the Malanbian to Doulingao formations(or upper part of the Liujiatang Formation) in central Hunan,and the Yingtang Formation in northern Guangxi.