Ophiceras(蛇菊石)在滇东卡以头组的发现及其意义

THE DISCOVERY OF Ophiceras IN THE KAYITOU FORMATION IN EASTERN YUNNAN PROVINCE AND ITS SIGNIFICANCE

Ophiceras(蛇菊石)在滇东海陆交互相卡以头组下部(25层下部)的首次发现,是近期海陆交互相和陆相二叠系-三叠系界线(PTB)研究的重要进展之一。该化石的发现为滇东卡以头组地层时代的确定提供了更加确凿的依据。在煤山D剖面,29-37层为Ophiceras(蛇菊石)的顶峰带,因此,可将滇东密德B剖面的25层与煤山D剖面29层对比,那么滇东地区卡以头组主体(甚至全部)的时代可划归早三叠世。

Ophiceras has been discovered for the first time in the Kayitou Formation （marine-terrestrial transitional facies） in eastern Yunnan Province. This is an important discovery in the study of Permian-Triassic Boundary（PTB）sections of the terrestrial and marine-terrestrial transitional facies. It provides solid basis for the geological age and the correlation of the Kayitou Formation with the stratotype section （Meishan D Section）. In the Meishan D Section, Ophiceras apex Zone occurs in Bed 29--37. Thus, Bed 25 of the Kayitou Formation can be correlated with Bed 29 at the Meishan D Section, and Kayitou Formation in eastern Yunnan Province is mainly of Early Triassic age.