贵州省六枝县郎岱“法郎组”的牙形石及其时代意义  

Conodonts of the "Falang Formation" from Langdai, Liuzhi County, Guizhou Province and Their Age Significance

作　　者：杨守仁[1] 郝维城[1] 江大勇[1] 

机构地区：[1]北京大学地质博物馆,100871

出　　处：《地质论评》2002年第6期586-592,共7页Geological Review

摘　　要：本文描述了采自贵州省六枝县郎岱剖面“法郎组”的一些牙形石。该牙形石群主要由Paragondolella polygnathiformis, P. maantangensis, P. tadpole, P. navicula navicula, P. foliata foliata, P. foliatainclinata, P. jiangyouensis, P. langdaiensis Yang sp. nov.等组成,自下而上可识别出3个牙形石带:竹杆坡组Paragondolella polygnathiformis-Paragondolella maantangensis组合带、Paragondolella polygnathiformis-Paragondolella tad pole组合带、瓦窑组Paragondolella polygnathiformis带。因此,该剖面“法郎组”的时代,不仅上部(当前的瓦窑组),而且下部(当前的竹杆坡组),都是晚三叠世卡尼期的。Conodonts collected from the Langdai section at Liuzhi County, Guizhou Province are described in this paper. This conodont fauna consists mainly of Paragondolella polygnathiformis, P. maantangensis, P. tadpole, P. foliata foliata, P. foliata inclinata, P. Jiangyouensis, P. langdaiensis Yang sp. nov. , P. navicula navicula. Three conodont zones are recognized in ascending order; the Paragondolella polygnathiformis-Paragondolella maantangensis Assemblage Zone, Paragondolella polygnathiformis-Paragondolella tadpole Assemblage Zone, and Paragondolella polygnathiformis Zone. This indicates that the age of the 'Falang Formation' in that section, not only the upper 'Falang Formation' (the present Wayao Formation), but also the lower 'Falang Formation' (the present Zhuganpo Formation), are Carnian of the Late Triassic.Paragondolella langdaiensis Yang sp. nov. (plate 1, figs. 4-6)Derivation nominis: With regard to the stratigraphical locality position(Langdai)Holotype: PL 1,Figs. 4-6, 95LD1-7y/2001005-7Locus typicus: Erguanzhai Village, Langdai District, Liuzhi County ,Guizhou Province, ChinaStratumtypicum: The Lower Carnian, Zhuganpo Formation, sample 95LD1 - 7y/2001005-7, together with Paragondolella polygnathiformis, P. foliata foliata , P. sp. indet.Diagnosis: The basal edge more or less arched in a lateral view before the pit. Denticles of carina in respect to the basal edge posteriorly inclined. The 'keel' protruded posteriorly, and the pit located at the posterior fourth of the unit.Description: The unit is slender and elongate. The carina consists of 18 fused denticles. The Basal edge is more or less arched in a lateral view before the pit. The denticles of carina are inclined posteriorly with respect to the basal edge. The upper edge of carina is straight, but the downward stepping of the platform in a lateral view is clear. The 'keel' is slightly elevated, and strongly protruding, with excavated groove, widen at the posterior fourth of the unit. The pit located at the posterior fourth of the unit rounded, and fr

关 键 词：“法郎组” 牙形石群 晚三叠世 卡尼期 贵州 六枝县 郎岱剖面 中国 

分 类 号：Q915[天文地球—古生物学与地层学]