贵州安龙坡脚剖面中三叠世安尼期牙形石的发现及其意义  

Discovery and significance of the conodonts( Anisian,Middle Triassic) from Pojiao section in Anlong area,Guizhou Province

作　　者：谢韬[1] 刘石磊 楼雄英[1] 胡智丹 周长勇[1] 黄金元[1] 文芠[1] XIE Tao;LIU Shilei;LOU Xiongying;HU Zhidan;ZHOU Changyong;HUANG Jinyuan;WEN Wen(Chengdu Center of China Geological Survey, Chengdu, Sichuan, 610081)

机构地区：[1]中国地质调查局成都地质调查中心,成都610081

出　　处：《地质论评》2019年第2期280-288,共9页Geological Review

基　　金：中国地质调查局项目<贵州1:5万兴义县;郑屯;安龙县幅区域地质矿产调查>(编号:12120114068101);<南盘江成矿区贞丰和富宁地区地质矿产调查>(编号:DD20160020);国家自然科学基金项目<应用同步加速器X射线层析显微技术重建云南罗平中三叠世牙形石多分子器官>(批准号:41502013)的成果~~

摘　　要：贵州安龙坡脚剖面新苑组位于扬子地台和右江盆地交汇处,为中三叠世台缘斜坡相沉积,在该组中上部发现了牙形石动物群,除少量分枝分子外,都归属于Neogondolella属,建立了4个牙形石带,自下而上分别为:Neogondolella bulgarica、Neogondolella bifurcata、Negondolella constricta、Neogondolella constricta cornuta(未见顶界)带。时代为中三叠世安尼中晚期,其特殊的古地理位置,对系统研究与对比罗平生物群、盘县动物群的古生态环境,以及区域地层对比、地层格架建立,探讨该时期盆地演化提供了基础资料。Objectives: The Pojiao section is located at the junction of Yangtze platform and Youjiang basin in Anlong county,Guizhou Province. Because of its special paleogeographic position,the research of the Pojiao section is useful for the comparison among Anlong area,Luoping Biota and Panxian Fauna in paleoecologcial environment and regional stratigraphy. It can help to build the stratigraphic framework.Methods: The main methods of this investigation are surveying section and conodont biostratigraphy in detail.At the same time,we study regional correlation of the strata in the southwestern margin of the Yangtze platform.Results: A group of conodonts were discovered in the Pojiao section,belonging to middle and upper part of the Xinyuan formation. Besides few ramiform elements,most elements are classified into the Genus Neogondolella.Four conodont zones have been established from bottom to top: Neogondolella bulgarica Zone,Neogondolella bifurcata Zone,Negondolella constricta Zone and Neogondolella constricta cornuta Zone( the top undefined).According to lithologic character,we divided the section into third parts. It was composed of sandy mudstone,limestone and calcirudite.Conclusions: The Xinyuan Formation in Pojia section is a platform-margin slope facies stratum of Middle Triassic. The appearance of conodonts indicate that the strata of this period was close to but not enter the Latinian period,belonging to the mid-and late-Anisian. This research has important significance for exploring basin evolution in this period.

关 键 词：新苑组 安尼期 牙形石 罗平生物群 贵州安龙 

分 类 号：Q915.2[天文地球—古生物学与地层学]