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文摘
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江南造山带雪峰隆起区元古宙浊积岩的地球化学组成良好地反映了沉积盆地的板块构造性质，并为解释区域大地构造的性质和演化提供了有用的信息。中元古代冷家溪群和新元古代板溪群（包括下部马底驿组和上部五强溪组）地层上主元素成分上无明显区别，总体上以中等SiO_2含量和K_2O/Na_2O比值经及较高的(Fe_2O_3~*+MgO)含量为特征。稀土元素球粒陨石标准化曲线与典型的后太古宙页岩（如PAAS或NASC）和上陆壳相似，以轻稀土富集、显著的铕负异常和重稀土平坦为牲。大离子亲石元素和铁镁元素的含量中等。主元素和微量元素特征指示了研究区元古宙浊积岩很可能代表了一套活动大陆边缘弧后沉积盆地的产物。陆内裂谷盆地模式对于解释新元古代华南地区的构造性质和演化可能并不合适。华夏陆块与扬子陆块的拼接以及Rodinia超大陆的最终形成可能发生在约0.8Ga左右的晋宁（雪峰）造山运动期，而不是全球Grenville造山期末的四堡（东安）运动期。 |
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其他语种文摘
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he geochemieal compositions of the Proterozoic turbidites in the Jiangnan orogenic: bell well reflect plate tectonic: setting of the sedimentary basin and provides some useful information for interprelation of I he nature and evolutionary history of the regional tectonics of South China. In terms of major element compositions, different Prolerozoic groups and formations have no distinct differences and on the whole are characterized by intermediate SiO_22 contents and K_2O/Na_2O ratios and relatively high Fe_2O_3 + MgO contents. The REE distribution patterns are uniform and similar to typical posl-Archean shales (e. g., PAAS and NASC) and the upper continental crust, with LREE enrichment, flat HREE, and significant negative Eu-anomalies. Abundances of ferromagnesum trace elements and large-ion lithophile (LIL) elements are moderate. Characteristics of major and trace elements indicate that the Proterozoic turbidites of the study area most probably represent the infill of an active continental back arc basin. An intracontinental rift model, as proposed by some workers, is invalid as interpreting the Neoprolo.roy.oie. tectonic setting of South China. Suturing between the Yangtze and Cathaysia blocks as well as the final assembly of the supercontinent Rodinia in South China occurred during the Jingning (Xuefeng) orogeny at around 0. 8 Ga, rather than the Sibao (Dong'an) orogeny at the late stage of the global Grenville movement. |
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来源
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地球化学
,2003,32(5):406-426 【核心库】
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关键词
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地球化学制约
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构造背景
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浊积岩
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元古宙
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雪峰隆起
;
江南造山带
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地址
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1.
中国科学院地球化学研究所, 贵州, 贵阳, 550002
2.
中国科学院地质与地球物理研究所, 北京, 100029
3.
茵斯布鲁克大学矿物与岩石研究所, 奥大利, 茵斯布鲁克
4.
成都理工大学地球科学学院, 四川, 成都, 610059
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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0379-1726 |
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学科
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地质学 |
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基金
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国家自然科学基金
;
奥地利国家科学基金
;
中国科学院“百人计划”项目
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国家973计划
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文献收藏号
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CSCD:1164868
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