喻学惠. 1992: 秦巴地区碱性岩与造山带构造演化关系及其特征. 地质通报, (3): 233-240.
    引用本文: 喻学惠. 1992: 秦巴地区碱性岩与造山带构造演化关系及其特征. 地质通报, (3): 233-240.
    YU Xue-hui. 1992: THE RELATION OF ALKALINE ROCKS IN THE QINLINGDABA MOUNTAINS REGION AND THE TECTONIC EVOLUTION OF THE OROGEN AND THEIR FEATURES. Geological Bulletin of China, (3): 233-240.
    Citation: YU Xue-hui. 1992: THE RELATION OF ALKALINE ROCKS IN THE QINLINGDABA MOUNTAINS REGION AND THE TECTONIC EVOLUTION OF THE OROGEN AND THEIR FEATURES. Geological Bulletin of China, (3): 233-240.

    秦巴地区碱性岩与造山带构造演化关系及其特征

    THE RELATION OF ALKALINE ROCKS IN THE QINLINGDABA MOUNTAINS REGION AND THE TECTONIC EVOLUTION OF THE OROGEN AND THEIR FEATURES

    • 摘要: 秦巴地区碱性岩种类繁多,既有碱性和过碱性系列的正长岩和霞石正长岩类,也有碱性辉长岩和碳酸盐岩。据Rb-Sr及C、O同位素资料,它们形成于元古代末期(晋宁期)—中生代(燕山期),其延续时间较长,并具有地幔来源的特征。南、北碱性岩带分别沿秦岭造山带与扬子地台北缘和华北地台南缘之间的边界断裂分布,显示出碱性岩的形成受断裂带的控制。从碱性岩的岩石化学特点,以及秦巴区大地构造环境与演化关系分析,它并非是典型的大陆裂谷性质的碱性岩,而是一种特殊的过渡类型。该区岩石圈的“开、合”作用不仅形成了秦岭造山带近东西向的断裂构造格局,同时也为上地幔的部分熔融和碱性岩的形成,提供了热能和物质基础。

       

      Abstract: There are a great vaiiety of alkaline rocks in the Qinling-Daba Mountains region, including not only alkaline and peralkaline syenite-nepheline syenite but also alkaline gabbro and carbonatite. According to the Rb-Sr and C and O isotope data, they originated in the terminal Proterozoic (Jinningian Stage) -Mesozoic (Yanshanian Stage). They are characterized by long-continued activity and show mantle-derived reatures. The southern and northern alkaline rock belts are distributed along the Qinling orogen and the boundary fault between the northern margin of the Yangtze platform and the southern margin of the North China platform, respectively, which implies that the formation of alkaline rocks was controlled by the fault zone. The petrochemical features of alkaline rocks and their relation to the tectonic evolution of the Qinling orogen indicate that they are not typical alkaline rocks of continental rift nature but a special transitional type. The opening and closing of the lithosphere not only gave (?)ise to the framework of the nearly EW-trending fault tectonics of the Qinling orogen but also furnished heat and materials for partial melting of the upper mantle and formation of alkaline composition.

       

    /

    返回文章
    返回