中国上石炭统滑石板阶

THE HUASHIBANIAN STAGE OF UPPER CARBONIFEROUS IN CHINA

滑石板阶一名最初见于项礼文等 ( 1980 )的文章 ,阶名源自同名岩石地层单位——滑石板组 ,典型剖面位于贵州省盘县县城以东约 30 km的滑石板村。岩性以浅灰色厚层灰岩为主 ,局部夹白云岩 ,厚 315 .4 6 m。底界以化石 Pseudostaffella antiqua的始现为标志 ,顶界止于化石 Profusulinella priscoidea带之底。滑石板阶包含 2个带 Pseudostaffella antiqua- P. antiqua posterior带和 Pseudostaffella composita- P. paracompressa带 ;2个菊石带Reticuloceras guizhouense带及 Branneroceras branneri- Grastrioceras cf. cumbriensis带 ,还包含腕足类 Choristitesmansuyi- Plicatifera chaoi组合带。牙形刺仅在下部找到 ,归属于 N eognathodus symmetricus带。滑石板阶大致相当于国际地层表中的巴什基尔阶 ( Bashkirian)

The Huashibanian Stage was cited by Xiang Li wen et al . (1980), based on “the Huashiban Formation”, with its stratotype at the village of Huashiban, 30km the east of Panxian county, Guizhou Province. Type Huashibanian strata (315.46m thick) is composed mainly of greyish white to dark grey, massive limestones intercalated with dolomites and locally containing chert nodules and bands. They yield fusulinids Pseudostaffella antiqua Dutkevich, P. antiqua posterior Safonova, P. composita Grozdilova et Lebedeva, P. paracompressa Safonova, Eostaffella postmosquensis Kireeva, and Eostaffellina protvae Rauser; conodonts, Neognathodus symmetricus Lane and Idiognathoides sulcatus Higgins et Bouckaert; the ammonoides, Reticuloceras guizhouense Chao et Liang, R. reticulatum Phillips, Branneroceras branneri Smith and Gastrioceras cf. cumbriensis Bisat; brachiopods, Choristites mansuyi Chao, Plicatifera chaoi Grabau, Kutorginella tentoria Ching et Liao, Martinia lata Grober and Enteletina undata Ching et Liao. These faunas are indicative of the Pseudostaffella antiqua P. antiqua posterior zone below and Pseudostaffella composita P. paracompressa zone above, as well as the Neognathodus symmetricus , Reticuloceras guizhouense, Branneroceras branneri Gastrioceras cf. cumbriensis and Choristites mansuyi Plicatifera chaoi assemblage zones. The Huashibanian Stage lies conformably upon the Luosuan Stage, its base being marked by the first occurrence of Pseudostaffella antiqua, whereas the top limit by the firstoccurrence of Pseudostaffella antiqua, whereas the top limit by the first occurrence of Profusulinella priscoidea. This stage can be approxionately correlated with the middle part of the Bashkirian Stage of the international stratigraphic chart and with the basal part of the Atokan Stage of the North America.