地学前缘 ›› 2009, Vol. 16 ›› Issue (3): 220-230.

• 论文 • 上一篇    下一篇

卡拉麦里缝合带后碰撞期火山活动

  

  1. 1中国科学技术大学 地球和空间科学学院, 安徽 合肥 230026
    2合肥工业大学 资源与环境工程学院, 安徽 合肥 230009

  • 出版日期:2009-05-01 发布日期:2009-05-01
  • 通讯作者: 刘德良，男，教授，博士生导师，构造地质学专业。
  • 作者简介:作者简介：吴小奇(1982—),男,博士研究生,地球化学专业。
  • 基金资助:

    中国石油科技项目(0701C0107);国家自然科学基金项目(40702021);中国科学技术大学研究生创新基金项目(KD2007061)

 Postcollisional volcanism of Kalamaili suture zone

  1. 1School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China
    2College of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China

  • Online:2009-05-01 Published:2009-05-01

PDF (PC)

988

摘要：

卡拉麦里缝合带是北疆的一条重要界线,沿该带广泛发育晚古生代火山岩。这些火山岩具有LILE相对富集、HFSE相对亏损的特征,且具有较高的Nb、Zr、TiO2含量和Zr/Y、Nb/Y比值,SrNd同位素主要表现出亏损的特征。综合分析表明,这些火山岩形成于后碰撞期。对卡拉麦里缝合带而言,从西向东后碰撞火山岩的时代逐渐变新,表明该缝合带从西向东逐渐演化进入后碰撞期,这从侧面反映了卡拉麦里洋盆是从西向东逐渐关闭的。对卡拉麦里缝合带而言,在后碰撞期,岩石圈伸展减薄,软流圈地幔物质上涌并发生部分熔融,加上地幔对流作用强烈,使得缝合带下产生了大规模的幔源岩浆底垫;先前在洋壳消减期被流体交代提取过的岩石圈地幔也在低压高温下发生部分熔融,形成的熔体混染了底垫的软流圈物质并喷发,形成了晚古生代的后碰撞期火山岩。

关键词: 卡拉麦里缝合带;陆梁隆起;三塘湖盆地;晚古生代;火山岩;后碰撞期

Abstract:

Abstract:  Kalamaili suture zone is an important plate boundary in north Xinjiang, and there are plenty of Neopaleozoic volcanic rocks around itThese volcanic rocks are enriched in LILEs and relatively depleted in HFSEs, and they are  also characterized by high Nb, Zr, TiO2 contents and Zr/Y, Nb/Y ratios, and  depleted SrNd isotopesThe characteristics of these volcanic rocks suggest that they were produced in postcollisional periodThe postcollisional volcanic rocks around Kalamaili suture zone become younger from west to east, which indicates that this suture zone entered postcollisional period gradually from west to east, and  reflects that the Kalamaili Ocean had been closed gradually from west to eastAs to the Kalamaili suture zone in postcollisional period, the lithosphere extended and thinned, and the asthenosphere materials upwelled and  melted partially, and intensive mantle convection occurred, leading to a plenty of mantlederived magmas underplating the suture zoneThe lithospheric mantle metasomatized by fluid in subduction period  melted partially under decompression and high temperature, the resulting melts contaminated the underplating asthenospheric materials, and the erupted lavas became the Neopaleozoic postcollisional volcanic rocks

Key words:

Key words: Kalamaili suture zone; Luliang uprise; Santanghu basin; Neopaleozoic; volcanic rocks; postcollisional period

中图分类号: