地学前缘 ›› 2009, Vol. 16 ›› Issue (1): 248-260.

• 论文 • 上一篇    下一篇

华南东段加里东期花岗岩类形成构造背景探讨

  

  1. 1南京大学 地球科学与工程学院, 江苏 南京 210093
    2江西省地质调查研究院, 江西 南昌 330030

  • 出版日期:2009-02-02 发布日期:2009-02-02
  • 通讯作者: 舒良树
  • 作者简介:张芳荣(1969—),男,高级工程师,博士研究生,岩石学、矿物学、矿床学专业,长期从事区域地质调查和花岗岩研究工作。E-mail: zfrjxddy@sina.com
  • 基金资助:

    国家自然科学基金项目(40634022,40572118);教育部博士点基金项目(20060284008)

Discussions on the tectonic setting of Caledonian granitoids in the eastern segment of South China

  1. 1School of Earth Sciences and Engineering,Nanjing University,Nanjing 210093, China
    2Geological Inquiry and Investigation Institute of Jiangxi Province,Nanchang 330030, China

  • Online:2009-02-02 Published:2009-02-02

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摘要：

根据近年对区域地质调查取得的认识和前人的研究成果,研究了华南东段加里东期花岗岩类的地质产状、分布规律、形成时代以及Nd、Sr同位素特征;结合研究区超镁铁质镁铁质岩及火山岩的形成时代、震旦纪—奥陶纪的沉积环境、加里东期构造事件的构造变形特征,对加里东期花岗岩类的形成背景进行了探讨。结果表明,加里东期花岗岩类形成于410～460 Ma,大部分岩体属于S型花岗岩,岩浆来源于地壳物质的部分熔融;极少数为I型花岗岩,有幔源物质参与。研究区在早古生代不存在与俯冲有关的弧火山岩,也不存在大面积的早古生代I型花岗岩,震旦纪—奥陶纪地层主要形成于浅海环境。研究提出,加里东期花岗岩类主体形成于板内构造环境。

关键词: 花岗岩类;地质特征;构造背景;加里东期;华南东段

Abstract:

Abstract:  Based on our newly firsthand data obtained recently from regional geological survey and previous research results, we have analyzed in detail the geological features, distribution, forming ages and NdSr isotopic characteristics of Caledonian granitoids in the eastern segment of South China.The tectonic setting forming Caledonian granitoids were discussed, which includes the ages of ultramaficmafic rocks and volcanic rocks that outcrop in the study areas, the deposited environment of sedimentary rocks during the SinianOrdovician period, and deformation patterns of the Caledonian structures.Results suggest that the Caledonian granitoids were mainly formed between 410460 Ma corresponding to the period from the Middle Ordovician to the Early Devonian. Geochemically, most of granitoids belong to the Stype that their magma were derived from the partial fusion of continental crust,but a few granitoids show characteristics of type I granitoids that the magma contains mantle materials. There is neither a largescale Caledonian type I granitoids that were related to plate subduction, nor the synchronous island arctype volcanic rocks in the study area; the sedimentary environment during the SinianOrdovician period is mainly a shallow sea and partly a bathyal one. We propose that the tectonic setting forming Caledonian granitoids  mainly belongs to intraplate tectonic environment.

Key words:

Key words: granitoids; geological features; tectonic setting; Caledonian period; eastern segment of South China

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