【摘要】 近年来的研究表明 ,双峰式火山岩套可以形成于大陆裂谷、洋内岛弧、活动大陆边缘、弧后盆地等多种环境。Sm -Nd同位素与不活动微量元素 (REE ,Zr ,Ti,Th ,Nb等 )相结合 ,进行综合研究 ,可帮助判断双峰式火山岩套成因和形成环境。本文总结了不同环境产出的双峰式火山岩组合的岩石学和微量元素、稀土元素、同位素地球化学特征 ,并根据对北祁连边马沟双峰式火山岩研究提出了其形成环境可能为岛弧环境 ,这一认识对探讨该地区造山带演化的地球动力学具有一定的意义 ,对在该地区的找矿工作也有一定的启发。更多还原

【Abstract】 Recent study has shown that bimodal volcanic suites can be formed in different tectonic environments, such as continental rifts, island arcs, active continental margins and back\|arc basins. It is considered that a combined use of the Sm\|Nd system with immobile trace elements (such as REE, Zr, Ti, Th, Nb) may be very useful to the interpretation of their petrogenesis and initial tectonic settings. In this paper, the petrological and geochemical characteristics of bimodal volcanic suites from different environments are summarized. It is suggested that the bimodal volcanics from Bianmagou, North Qilian, were formed in an island arc environment. This is of some significance to the study of the geodynamic evolution of the North Qilian orogenic belt, and also to ore\|search in this area.\;更多还原