贵州望谟下-中三叠统的牙形石生物地层  

Lower-Middle Triassic Conodonts of Ganheqiao Section, Wangmo County, Guizhou Province

作　　者：梁蕾 吴奎[3] 田力 童金南[2] Liang Lei;Wu Kui;Tian Li;Tong Jinnan(Hebei International Joint Research Center for Paleoanthropology,School of Earth Sciences,Hebei GEO University,Shijiazhuang 050031,China;State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences,Wuhan 430078,China;Hubei Institute of Geosciences,Wuhan 430034,China)

机构地区：[1]河北地质大学河北省古人类形态与演化国际联合研究中心,地球科学学院,河北石家庄050031 [2]中国地质大学生物地质与环境地质国家重点实验室,湖北武汉430078 [3]湖北省地质科学研究院,湖北武汉430034

出　　处：《地球科学》2025年第1期19-32,共14页Earth Science

基　　金：国家自然科学基金项目(Nos.42030513,42202033,42272361,42102011);河北省自然科学基金项目(No.D2020403072);生物地质与环境地质国家重点实验室开放基金项目(No.GBL21903);河北省高等学校科学技术研究项目(No.BJ2021011);河北地质大学博士科研启动基金(No.BQ2018036)。

摘　　要：三叠纪初现代型生态系统建立的过程曲折并伴随着频繁的环境波动,研究其模式和驱动机制需要以高分辨率的地层格架为基础建立可靠的时间标尺.虽然牙形石在古生代和早中生代海相地层对比与划分中往往被作为标准化石,但是由于早-中三叠世的多个阶和亚阶的国际划分与对比标准一直悬而未决,目前提出的一些候选标准化石还有待进一步的区域与全球对比的检验.通过对贵州望谟甘河桥剖面的下-中三叠统底部样品进行了系统的牙形石分类学和地层学研究,共鉴定出15属29种,建立了10个牙形石组合带,由下而上依次为Neospathodus dieneri带、Novispathodus waageni带、Guangxidella bransoni带、Novispathodus pingdingshanensis带、Icriospathodus crassatus带、Triassospthodus homeri带、Triassospthodus triangularis带、Triassospthodus sosioensis带、Chiosella timorensis带和Nicoraella germanica带.根据本剖面牙形石分布情况以及和其他剖面对比,支持以牙形石Novispathodus waageni、Novispathodus pingdingshanensis、Chiosella timorensis分子的首现分别作为印度阶-奥伦尼克阶、史密斯亚阶-斯帕斯亚阶以及下-中三叠统界线的标准.过去几年,望谟地区的三叠系中陆续报道了多个层位的海洋爬行动物和较为多样的节肢动物化石,标志着海洋生态系统发生了多阶段的演化.本文建立的高分辨率生物地层框架,为卡定研究区现代型海洋生态系统的建立时间,提供了关键证据.The establishment of modern ecosystem in Early Triassic is challenging and subject to frequent fluctuation of environment,thus a refined time scale is demanded to explore its process and mechanism.Although conodonts are often used as index fossils in the correlation and division of Paleozoic and Early Mesozoic marine strata,the international classification and comparison criteria for multiple stages and substages of the Early-Middle Triassic have been pending.Some candidate index fossils have yet to be further tested by regional and global correlation.The deep-water strata were well developed in the Lower-Middle Triassic at the Ganheqiao Section in Wangmo County of Guizhou.In this paper,a systematic study of conodont taxonomy and stratigraphy was carried out on the samples near the Lower-Middle Triassic boundaries of the section.A total of 29 species in 15 genera were identified and 10 conodont zones were recognized,namely Neospathodus dieneri Zone,Novispathodus waageni Zone,Guangxidella bransoni Zone,Novispathodus pingdingshanensis Zone,Icriospathodus crassatus Zone,Triassospthodus homeri Zone,Triassospthodus triangularis Zone,Triassospthodus sosioensis Zone,Chiosella timorensis Zone,Nicoraella germanica Zone in ascending order.According to the distribution of conodonts in this section and the comparison with other sections,it is supported that the first occurrences of conodonts Novispathodus waageni,Novispathodus pingdingshanensis and Chiosella timorensis are used as the criteria for the Indian-Olenekian,Smithian-Spathian and Lower-Middle Triassic boundaries,respectively.In the past few years,multiple layers of marine reptiles and diverse arthropod fossils have been reported in the Triassic in the Wangmo area,indicating a multi-stage evolution of marine ecosystems.The high-resolution biostratigraphic framework established in this paper provides key evidence to calibrate the build-up time of modern marine ecosystems in study area.

关 键 词：牙形石 史密斯-斯帕斯亚阶界线 下-中三叠统界线 地球生物学 

分 类 号：P52[天文地球—古生物学与地层学]