豫北林州地区寒武系苗岭统古丈阶碳同位素组成特征及其地层学意义
Carbon isotopic composition of Guzhangian,Miaolingian,Cambrian in Linzhou area,northern Henan and its stratigraphic significance
陈泳霖 1郭振 1李瑞强 2白国典1
作者信息
- 1. 河南省地质研究院,河南 郑州 450016;地质过程与矿产资源国家重点实验室河南技术联合研发和示范中心,河南 郑州 450016
- 2. 河南省地质研究院,河南 郑州 450016
- 折叠
摘要
近年来,有研究者在豫西登封地区发现张夏组三段和四段的碳同位素存在一个-1.5‰的负漂移,经过对比推测该负漂移位于鼓山阶与古丈阶的界线处,但没有讨论研究剖面的生物地层信息,因而其准确性存在疑问.为了研究华北地台寒武系苗岭统内部年代地层格架,本文针对豫北林州地区寒武系张夏组、崮山组、炒米店组碳酸盐岩进行了碳同位素学、三叶虫生物地层学和沉积学综合研究.结果显示,苗岭统内部碳酸盐岩δ13C组成相对稳定,基本保持在0.5‰附近,但在张夏组顶部到炒米店组底部存在一个较小幅度的碳同位素负漂移,δ13C值从1.3‰逐渐减小到-0.1‰,漂移的峰值对应于三叶虫Blackwelderia的首现层位.通过对比华南、美国、澳大利亚和西伯利亚等地区同时期地层的碳同位素演化曲线,确认该次碳同位素负漂移具有普遍性,指示了苗岭统古丈阶的底界.
Abstract
In recent years,a negative shift of carbon isotope of-1.5‰ has been found in the 3rd and 4th member of Zhangxia Formation in Dengfeng area of western Henan Province.The negative shift is presumed to be located at the boundary between Gushan stage and Guzhang Stage by comparison.However,the biostratigraphic information of the study section has not been discussed,so its accuracy is doubtful.In order to study the internal chronostratigraphic framework of Miaolingian,Cambrian in North China Platform,a comprehensive study of carbon isotope,trilobite biostratigraphy and sedimentology has been carried out on the carbonates of Zhangxia Formation,Kushan Formation and Chaomidian Formation in Linzhou area of northern Henan.Results show that the δ13C composition of the internal carbonate rocks of the Miaolingian is relatively stable,basically maintaining around 0.5‰,but there is a small amplitude of negative carbon isotope shift from the top of the Zhangxia Formation to the bottom of the Chaomidian Formation,and the δ13C value gradually decreases from 1.3‰ to-0.1‰.The peak value of the shift corresponds to the first occurrence of the trilobite Blackwelderia.By comparing the carbon isotope evolution curve of the strata in South China,the United States,Australia,Siberia and other regions at the same time,it is confirmed that this negative carbon isotope shift is universal,indicating the bottom of the Miaoling Series Guzhangian stage.
关键词
碳同位素/崮山组/寒武系/豫北地区Key words
carbon isotope/Kushan Formation/Cambrian system/Northern Henan region引用本文复制引用
基金项目
河南省自然科学基金(202300410024)
河南省地质研究院院管省财政项目(2023-901-XM002-KT01)
河南省地质研究院院管省财政项目(2023-909-XM019-KT02)
出版年
2024
NETL
NSTL
维普
万方数据