Carbon Isotope from Shallow Marine System in North China:Implications for Stratigraphical Correlation and Sea-Level Changes in Cambrian  

作　　者：Jingxun Zuo Xuejian Zhu Yonglin Chen Wenjian Zhai 

机构地区：[1]Henan Institute of Geological Survey,Zhengzhou 450001,China [2]Nanjing Institute of Geology and Paleontology,Chinese Academy of Sciences,Nanjing 210008,China

出　　处：《Journal of Earth Science》2023年第6期1777-1792,共16页地球科学学刊（英文版）

基　　金：sponsored by the National Natural Science Foundation of China(Nos.41672028 and 41672002);the 2020 Provincial Natural Science Foundation of Henan.

摘　　要：Cambrian System at the Shatan Section in northern Henan,North China,consists of sedimentary successions of tidal flat and shallow-water carbonate platform facies.Data of carbon isotope(δ^(13)C_(carb))from this section reveals five positive δ^(13)C_(carb)(P_(st-1)-P_(st-5))and five negative δ^(13)C_(carb) excursions(N_(st-1)-N_(st-5)).In the positive excursions,δ^(13)C_(carb) rises to 0.88‰,1.05‰,2.04‰,1.00‰ and 2.97‰,respectively,while in the negative excursions δ^(13)C_(carb) drops to -8.00‰,-3.50‰,-1.00‰,-0.33‰ and around -2.00‰,respectively.On the basis of chronostratigraphy of Cambrian,the most remarkable carbon isotope excursions can be correlated regionally and globally.In addition,one second-order and ten third-order sequences have been recognized at this section.Correlating third-order sequences and chemostratigraphy indicates that carbonates from the basal part of the transgression system tract(TST)and the upper part of the high-water system(LHST)generally have lighter δ^(13)C_(carb) values,whereas massive carbonates with microbialite from the lower part of the high-water system tract(EHST)usually have heavier δ^(13)C_(carb) values.The association of δ^(13)C_(carb) values with sea-level fluctuations suggests that the positive carbon isotope excursions or high δ^(13)C_(carb) values may have been caused by an increase in the marine primary productivity in response to maximum seawater flooding during the transgression.

关 键 词：carbon isotope sedimentary rocks sea-level change shallow-water Cambrian System STRATIGRAPHY North China 

分 类 号：P597[天文地球—地球化学] P534.41[天文地球—地质学] P731.23