The Termination and Aftermath of the Lomagundi -Jatuli Carbon Isotope Excursions in the Paleoproterozoic Hutuo Group, North China  

作　　者：Zhenbing She Fanyan Yang Wei Liu Luhua Xie Yusheng Wan Chao Li Dominic Papineau 

机构地区：[1]State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China [2]School of Earth Sciences, China University of Geosciences, Wuhan 430074, China [3]Ningxia Geology And Mineral Resources Centre Lab, Yinchuan 750021, China [4]Tianjin Research Institute for Water Transport Engineering, M. O. T., Tianjin 300456, China [5]State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [6]Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China [7]Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China [8]London Centre for Nanotechnology, University College London, London [9]Department of Earth Sciences, University College London, 17-19 Gower Street, London, United Kingdom

出　　处：《Journal of Earth Science》2016年第2期297-316,共20页地球科学学刊（英文版）

基　　金：National Natural Science Foundation of China (No. 41272038);National Universities, China University of Geosciences (Wuhan), State Key Laboratory of Biogeology and Environmental Geology,China University of Geosciences (No. GKZ14Y660);the 111 Program for the Ministry of Education of China;the State Administration of Foreign Expert Affairs of China (No. B07039)

摘　　要：The Lomagundi-Jatuli Event（LJE） is one of the largest and earliest positive carbon isotope excursions preserving δ^（13）C_（carb） values between ＋5 and ＋16‰ in Paleoproterozoic carbonates worldwide. However, the duration, amplitude and patterns of these excursions remain poorly constrained. The 2.14-1.83 Ga Hutuo Group in the North China Craton is a 〉10 km thick volcano-sedimentary sequence, including 〉5 km thick well-preserved carbonates that were deposited in supra-tidal to sub-tidal environments. C-O isotopic and elemental analyses of 152 least altered samples of the carbonates revealed a three-stage δ^（13）C evolution. It began with an exclusively positive δ^（13）C_（carb）（＋1.3 to ＋ 3.4‰） stage in the ~2.1 Ga carbonate in the Dashiling and Qingshicun Formations, followed by a transition from positive values to oscillating positive and negative values in ~3 000 m thick carbonates of the Wenshan, Hebiancun, Jianancun, and Daguandong Formations, and end with exclusively negative δ^（13）C_（carb） values preserved in 〉 500 m thick dolostones of the Huaiyincun and Beidaxing Formations. It appears that much of the LJE, particularly those extremely positive δ^（13）C_（carb） signals, was not recorded in the Hutuo carbonates. The exclusively positive δ^（13）C_（carb） values（＋1.3 to ＋ 3.4‰） preserved in the lower formations likely correspond to the end of the LJE, whereas the subsequent two stages reflect the aftermath of the LJE and the onset of Shunga-Francevillian event（SFE）. The present data point to an increased influence of oxygen on the carbon cycle from the Doucun to the Dongye Subgroups and demonstrate that the termination of the LJE in the North China Craton is nearly simultaneous with those in Fennoscandia and South Africa.The Lomagundi-Jatuli Event（LJE） is one of the largest and earliest positive carbon isotope excursions preserving δ^（13）C_（carb） values between ＋5 and ＋16‰ in Paleoproterozoic carbonates worldwide. However, the duration, amplitude and patterns of these excursions remain poorly constrained. The 2.14-1.83 Ga Hutuo Group in the North China Craton is a 〉10 km thick volcano-sedimentary sequence, including 〉5 km thick well-preserved carbonates that were deposited in supra-tidal to sub-tidal environments. C-O isotopic and elemental analyses of 152 least altered samples of the carbonates revealed a three-stage δ^（13）C evolution. It began with an exclusively positive δ^（13）C_（carb）（＋1.3 to ＋ 3.4‰） stage in the ~2.1 Ga carbonate in the Dashiling and Qingshicun Formations, followed by a transition from positive values to oscillating positive and negative values in ~3 000 m thick carbonates of the Wenshan, Hebiancun, Jianancun, and Daguandong Formations, and end with exclusively negative δ^（13）C_（carb） values preserved in 〉 500 m thick dolostones of the Huaiyincun and Beidaxing Formations. It appears that much of the LJE, particularly those extremely positive δ^（13）C_（carb） signals, was not recorded in the Hutuo carbonates. The exclusively positive δ^（13）C_（carb） values（＋1.3 to ＋ 3.4‰） preserved in the lower formations likely correspond to the end of the LJE, whereas the subsequent two stages reflect the aftermath of the LJE and the onset of Shunga-Francevillian event（SFE）. The present data point to an increased influence of oxygen on the carbon cycle from the Doucun to the Dongye Subgroups and demonstrate that the termination of the LJE in the North China Craton is nearly simultaneous with those in Fennoscandia and South Africa.

关 键 词：PALEOPROTEROZOIC Lomagundi-Jatuli event Hutuo Group carbon isotope carbonate. 

分 类 号：P597[天文地球—地球化学] P534.3[天文地球—地质学]