豫北林州地区鼓山阶底部碳同位素组成及演化趋势  

Carbon isotope composition and its evolution around the base of the Drumian Stage in Linzhou area,northern Henan

作　　者：陈泳霖 王玺 王艳慧[1] 姚帅 白国典[1] 方怀宾[1] Chen Yonglin;Wang Xi;Wang Yanhui;Yao Shuai;Bai Guodian;Fang Huaibin(Henan Institute of Geological Survey,Zhengzhou 450001,China;Key Laboratory of Metallogenic Geological Process and Resource Utilization of Metal Mineral Resources of Henan Province,Zhengzhou 450001,China)

机构地区：[1]河南省地质调查院,郑州450001 [2]河南省金属矿产成矿地质过程与资源利用重点实验室,郑州450001

出　　处：《地质科技通报》2022年第5期132-140,149,共10页Bulletin of Geological Science and Technology

基　　金：河南省自然科学基金项目(202300410024);河南省地质调查院科技创新基金项目(豫科创[2021]KC-01)。

摘　　要：碳同位素地层学是寒武系地层划分与对比的重要手段。通过对豫北驴驮沟剖面碳酸盐岩地层进行碳同位素分析发现,驴驮沟剖面寒武系鼓山阶(Drumian)底界附近的碳酸盐岩的δ^(13) C值分布于3.1‰~-1.7‰之间,δ^(18) O值分布于-3.9‰~-9.4‰之间。δ^(13) C、δ^(18) O之前的非协变关系指示碳同位素组成比较稳定。鼓山阶底界附近δ^(13) C表现为负漂移演化趋势,漂移幅度为3.0‰,最低值为-1.7‰,出现在三叶虫Proasaphiscus首现位置15 m之下。出现负漂移的位置和负漂移的幅度与华南湘西王村剖面、美国犹他州Drum Mountains等剖面的鼓山阶底部的负漂Drum carbon isotope excursion(DICE)一致,表明DICE负漂移具有洲际对比意义,可作为寒武系鼓山阶划分和对比的工具。负漂移峰值处岩性为位于青灰色页岩之间的薄层灰岩夹层,超覆于鲕粒灰岩之上,因此,寒武系鼓山阶底部附近的DICE负漂移对应于苗岭世早期的海侵时期。Carbon isotope stratigraphy is an important means to subdivide and correlate the Cambrian strata.Based on the carbon isotope analysis of the carbonate strata of Lütuogou Section,northern Henan Province,it is found theδ^(13) C value of carbonate samples collected from the base of the Drumian Stage at Lütuogou Section,northern Henan,ranges from 3.1‰to-1.7‰,and theδ^(18) O value ranges from-3.9‰to-9.4‰.No covariance exists betweenδ^(13) C andδ^(18) O,which implies that the carbon isotope composition is nearly stable.Value ofδ^(13) C around the base of the Drumian Stage consists of a negative excursion,the amplitude of the negative excursion is 3.0‰,and the minimum value ofδ^(13) C is-1.7‰,which occurs at the place 15 m below the first occurrence of trilobite protasaphiscus.The position and amplitude of the negative excursion are similar to those of the drum carbon isotope excursion(DICE)tested in the Wangcun Section,western Hunan,South China,and the Drum Mountains section in Utah,USA,which suggests that the DICE can be used as a global indicator for the correlation of the Drumian Stage.Furthermore,the cyan shale with thin limestone at the position of minimumδ^(13) C overlies the oolitic limestone;therefore,DICE occurs in the transgressive succession in the early Miaolingian.

关 键 词：碳同位素组成 DICE负漂移 鼓山阶 寒武系 

分 类 号：P597[天文地球—地球化学]