扬子板块西南缘南盘江盆地者堡一带二叠系-三叠系界线地质特征及牙形石生物地层  

Permian-Triassic Boundary Characteristics and Conodont Biostratigraphic in Zhebao Region of Nanpanjiang Basin,the Southwestern Margin of Yangtze Plate,China

作　　者：向坤鹏 贺永忠 安亚运 易成兴 赵磊 盘应娟 陈明华 XIANG Kun-peng;HE Yong-zhong;AN Ya-yun;YI Cheng-xing;ZHAO Lei;PAN Ying-juan;CHEN Ming-hua(Guizhou Institute of Geological Survey,Guiyang 550081,Guizhou,China)

机构地区：[1]贵州省地质调查院,贵州贵阳550081

出　　处：《地球科学与环境学报》2020年第4期479-489,共11页Journal of Earth Sciences and Environment

基　　金：中国地质调查局地质调查项目(DD20160020);贵州省地质矿产勘查开发局项目(QDKKH[2020]29);贵州省地质调查院院士工作站项目(QKHPTRC[2018]5626)。

摘　　要：扬子板块西南缘南盘江盆地在二叠纪末结束了孤立碳酸盐岩台地生长历史,但先成台地在早三叠世对沉积过程的控制作用尚不明确。选取盆地西北缘安然背斜东段者堡一带二叠系—三叠系界线为研究对象,在详细剖面测制基础上,进行系统的牙形石生物地层研究。结果表明:罗楼组下部灰岩段包含2个牙形石带,自下而上依次为Hindeodus praeparvus带与Hindeodus parvus带;根据区域剖面资料对比,可将二叠系—三叠系界线限定于剖面第4层1.5 m处。根据二叠系—三叠系界线剖面露头特征,结合区域资料综合分析,认为安然—者堡一带于晚二叠世长兴晚期经历了缓慢隆升→局部暴露形成岛屿并接受风化剥蚀→再次淹没接受沉积的过程。该研究为进行南盘江盆地二叠纪—三叠纪过渡时期古地理演化提供沉积学证据。The growth history of isolated carbonate platform in Nanpanjiang Basin,the southwestern margin of Yangtze plate,ends at the end of Permian,but the restriction of antecedent platform for the sedimentary process in Early Triassic is not yet clear.Permian-Triassic boundary of Zhebao region in the eastern Anran anticline of the northwestern margin of Nanpanjiang Basin was chose as research object,and the conodont biostratigraphy was studied systematically based on the detailed section measurement.The results show that the limestone in the lower part of Luolou Formation contains two conodont zones from the bottom up,including Hindeodus praeparvus zone and Hindeodus parvus zone;compared with several sections in Nanpanjiang Basin,Permian-Triassic boundary can be limited to 1.5 m in layer 4.According to the characteristics of Permain-Triassic boundary section,combined with the regional geological data,the Anran-Zhebao region experiences such a process of slow uplift,partial exposure as island and weathering,and submerging at last during Late Changhsingian.It provides sedimentology evidence for paleogeographic evolution research in Permian-Triassic transition period in Nanpanjiang Basin,South China.

关 键 词：二叠系—三叠系界线 罗楼组 微生物岩 牙形石 生物地层 长兴晚期 古地理演化 南盘江盆地 

分 类 号：P531[天文地球—古生物学与地层学] P535[天文地球—地质学]