贵州西南部“法郎组”牙形石及其时代

根据近年牙形石研究，在“法郎组”中从下而上识别了３个牙形石带：１、Ｎｅｏｇｏｎｄｏｌｅｌｌａｐｏｌｙｇｎａｔｈｉｆｏｒｍｉｓ－Ｎｅｏｇｏｎｄｏｌｅｌｌａｍａａｎｔａｎｇｅｎｓｉｓ组合带；２、Ｎｅｏｇｏｎｄｏｌｅｌｌａｐｏｌｙｇｎａｔｉｆｏｒｍｉｓ－Ｎ－ｅｏｇｏｎｄｏｌｅｌｌａｔａｄｐｏｌｅ组合带；３、Ｎｅｏｇｏｎｄｏｌｅｌｌａｐｏｌｙｇｎａｔｉｆｏｒｍｉｓ带。根据牙形石Ｎ．ｅｘｃｅｌｓａ谱系演化、牙形石发展事件、牙形石分带及其与国内外的牙形石带对比，论证了“法郎组”的时代，“法郎组”可解体为瓦窑组和竹杆坡组，全属晚三叠世卡尼期，而不是拉丁期。

Conodonts from the "Falang Formation" of Southwestern Guizhou and their age

Based on the recent study of conodonts, three conodont assemblage zones are recognized from the "Falang Formation" as follows (in ascending stratigraphical order ): 1.Neogondolella polygnathiformis-Neogondolella Maantangensis Assemblage Zone; 2.Neogondolella polygnathiformis-Neogondolella tadpole Assemblage Zone; 3.Neogondolella polygnathiformis Assemblage Zone. Based on the evolution of the Neogondolella excelsa stock, the events of conodont development, the zonation of conodonts and comparison with demestic and overseas conodont zones, the age of the "Falang Formation" is discussed. The "Falang Formation" can be replaced by two Formations,namely the Zhuganpo Formation and overlying Wayao Formation. Their ages are considered as Carnian of the Late Triassic (not Ladinian of the Middle Triassic).