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    中国晚前寒武纪年表和年代地层序列

    New Geological time scale of Late Precambrian in China and geochronology

    • 摘要: 提要:本文依据2009年11月24日全国地层委员会前寒武纪分会扩大会议上形成的一个共识,对中国晚前寒武纪年表进行重新标定:即长城系限定在1.8~1.6 Ga,包括常州沟组、串岭沟组、团山子组、大红峪组;蓟县系限定在1.6~1.4 Ga,包括高于庄组、杨庄组、雾迷山组、洪水庄组、铁岭组;待建系1.4~1.0 Ga,蓟县剖面上仅发育下马岭组;青白口系限定在1.0~0.78 Ga,包括骆驼岭组和景儿峪组;南华系限定在780~635 Ma及震旦系限定在635~542 Ma。关于最新的江南古陆晚前寒武纪地层中的一系列锆石U-Pb数据,应标定在青白口系上部。另外,华北古陆上最新的锆石U-Pb测年结果,初步揭示华北古陆前寒武系火山岩省的存在和分布范围,结合全球大陆动力学的基本特征,有利于我们建立一个前寒武纪统一的、精确的和具有年代系统的高精度年龄的基础剖面。

       

      Abstract: Abstract:The newly marked Precambrian stratigraphic column of China was discussed by the Subcommission on Precambrian of National Commission on Stratigraphy of China on November 24, 2009. According to the common understanding reached at this meeting, Changcheng System comprising Changzhougou, Chuanlinggou, Tuanshanzi and Dahongyu Formations is limited in 1.8-1.6 Ga, whereas the Jixian System consisting of Gaoyuzhuang, Yangzhuang, Wumishan, Hongshuizhuang and Tieling Formations is limited in 1.6-1.4 Ga. The unnamed system (1.4-1.0 Ga) only includes Xiamaling Formation in the Jixian section. The Qingbaikou System composed of Luotuoling and Jing’eryu Formations is limited in 1.0-0.78 Ga. The Nanhua System is between 780-635 Ma and the Sinian System is between 635-542 Ma in age. According to a series of SHRIMP U-Pb dating data from late Precambrian in Jiannan orogenic belt, the strata should be assigned to the upper part of the Qingbaikou System. Moreover, new zircon U-Pb dating data obtained in North China Platform reveals the existence and distribution of the volcanic province. In dealing with the basic global geodynamics, it is useful to set up a basic late Precambrian section with unified and high-precision chronological dating.

       

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