摘要
近年来,有关中国东南部中新生代地球动力学背景的研究已取得了重要的进展,主要体现在:地幔性质、岩石圈减薄、岩石圈伸展和构造背景四个方面。研究表明,中国东南部中新生代的地幔性质主体是亏损地幔和EM型富集地幔混合,中生代以富集地幔为主,而新生代主体为亏损地幔。中国东南部晚中生代经历了岩石圈减薄,并伴生了玄武质底侵作用,具有较为复杂的岩石圈增生—减薄过程。大量事实表明中国东南部中新生代存在多期岩石圈伸展事件,侏罗纪存在局部岩石圈伸展,主要集中于内陆地区,白垩纪经历了区域性岩石圈伸展。近二十年来,中国东南部大规模岩浆的构造背景一直存在着争论,焦点在于太平洋俯冲对中国东南部产生什么的影响。从目前已有的资料来看,白垩纪地幔源区受到太平洋俯冲的影响,太平洋俯冲和玄武质岩浆底侵诱发了地壳加厚,岩石圈拆沉和软流圈上涌而导致岩石圈伸展是中国东南部主要构造背景。但是,中国东南部晚中生代以来的岩石圈伸展—减薄及其深部动力学机制是目前急需进一步深入探讨的问题。
In recent year, many achievements in scientific research on Mesozoic and Cenozoic geodynamics setting in Southeast China have been made, which include mantle source, lithosphere thinning, lithosphere extension events and tectonics setting in southeast China. Geochemical and isotopic studies indicated that mantle source are composed of depleted asthenospheric mantle and enriched lithospheric mantle beneath the crust, the subcontinental lithospheric mantle（SCLM） are predominantly EM 11 lithospheric mantle in the Mesozoic while asthenospheric mantle in the Cenozoic in southeast China. It is suggested that the lithoshpheric thinning took place in the late Mesozoic accompanied by basaltic magma uderplating, which has complicated lithospheric accretion and thinning process beneath the crust in southeast China. Several lines of evidences demonstrated that lithospheric extension occurred in this region during the Late Mesozoic to Cenozoic. Moreover, local extension occurred in inland area of southeast China in the Jurassic while regional extension in the Cretaceous in southeast China. The tectonic setting that accounts for Mesozoic magmastism in southeast China has been an issue of little consensus since the last two decades and focused on whether the extensive magmatism province are related to Pacific plate subduction in the regions. From available data, it is thought that Cretaceous mantle sources have affected by Pacific plate subduction and basaltic magma underplating resulted in the lithospheric thinning and subsequent lithospheric delamination and asthenospheric upwelling. However, lithospheric extension-thinning and its deep process beneath the crust in the Mesozoic to Cenozoic in southeast China remains to be further studied.
出处
《地质论评》
CAS
CSCD
北大核心
2005年第6期613-620,共8页
Geological Review
基金
国家自然科学基金资助项目(编号40402011和40434011)
国家重点基础项目(编号G1999043211)
中国博士后基金资助项目
中国科学院创新项目(编号KZCX3-SW-125)
中国科学院地球化学研究所开放实验室基金资助项目(编号200402)的成果
关键词
地幔性质
岩石圈减薄
地壳拉张
构造背景
中国东南部
mantle source
lithospheric thinning
lithospheric extension
geodynamics setting
southeast China
作者简介
谢桂青，男，1975年生。2003年在中国科学院地球化学研究所地球化学专业获得博士学位，主要从事岩石学和成矿学研究。通讯地址：100037，北京阜外百万庄大街26号;电话：010--68999656；Email：guiqingxie@sohu．com。
