本站首页 | 项目介绍 | 项目内容 | 项目管理 | 下载中心 | 网站登录 | 后台管理 | 联系方式
 
 
通知公告
 
华北克拉通破坏2011年度学... [12-15]
张宏福会议海报 [06-23]
华北克拉通破坏2010年度学术会议... [12-20]
关于召开《华北克拉通破坏》年度... [11-19]
 
科普园地
 
什么是克拉通?什么是地台、地盾?
 
相关链接
 
国家自然科学基金委...
中国科学院
中国科学院地质与地...
中国地质大学(武汉...
中国科学院广州地球...
合肥工业大学
中国科学技术大学
中国地震局物探中心
 
访问统计
 
330841
 
  本站首页 >> 论文推荐
Secular evolution of the lithosphere beneath the eastern North China Craton: Evidence from Mesozoic basalts and high-Mg andesites
ABSTRACT:  Geochemical and isotopic data from Mesozoic lavas from the Jianguo, Niutoushan, Wulahada, and Guancaishan volcanic fields on the northern margin of the North China Craton provide evidence for secular lithospheric evolution of the region. Jianguo lavas are alkaline basalts with LILE- and LREE-enrichment ((La/Yb)N12.2–13.2) and MORB-like Sr-Nd-Pb isotopic ratios ((87Sr/86Sr)i0.704; Nd3.9–4.8; (206Pb/204Pb)i18). Niutoushan basalts are similar but show evidence of olivine fractionation. Wulahada lavas are high-Mg andesites (Mg#67) with EM1 Sr-Nd-Pb isotopic signatures. Geochemical data suggest that the basalts originated from MORB-type asthenosphere whereas the high-Mg andesites were derived an EM1 mantle source, i.e., a refractory lithospheric mantle modified by a previously subducted slab. The result, combined with the available data of the Mesozoic basalts from the southern portion of the NCC (Zhang et al., 2002), manifests a vast secular evolution of the lithospheric mantle beneath the eastern NCC from the Paleozoic refractory continental lithosphere to this Mesozoic modified lithosphere. Compared with the cratonic margin, the lithospheric mantle beneath the center of the craton was less extensively modified, implying the secular evolution was related to the subduction processes surrounding the NCC. Therefore, we suggest that the interaction of the slab-derived silicic melt with the old refractory lithospheric mantle converted the Paleozoic cratonic lithospheric mantle into the late Mesozoic fertile mantle, which was also different from the Cenozoic counterpart. A geodynamic model is proposed to illustrate such a secular lithosphere evolution.
地址:北京市朝阳区北土城西路19号 中国科学院地质与地球物理研究所 邮 编:100029
电话:010-82998240  传真:010-62010846 电子邮箱:yp@mail.iggcas.ac.cn