摘要
大同—集宁地区太古代变质杂岩由葛胡窑灰色片麻岩系和丰镇群变沉积岩系组成,两套岩石组合之间呈不整合接触。在葛胡窑灰色片麻岩系和丰镇群变沉积岩系中发育两期变质基性岩墙群,两套基性岩墙群与围岩一起发生了麻粒岩相变质和强烈变形。两期变质基性岩墙群在年龄、岩石学、结构构造、地球化学和REE等存在明显差别,表明它们形成于不同的大地构造环境中。该区基性岩墙群的广泛发育揭示了太古代末期华北克拉通稳定的硅铝壳已经建立,大规模裂隙系统已经形成。然而,变质基性岩墙群和原始产状现在很难测量。
The Archean metamorphic complexes of Datong-Jining region are composed of Gehuiyao gray gneisses and Feng ZHen group meta-sedimentary rocks (khondalite suites) and there is a tectonic unconformity between them, Two series of basic dyke swarms intruded into those two complexes have been found They have been metamorphosed in granulite facies and strongly deformed as their country rocks have. some evident differences between the two swarms have been identified in age, petrography, structure, scale of size, chemistry and REE etc. Which indicate that they were formed in different tectonic environments. The intrusion of the widely developed basic dyke swarms reveals that the stable ensialic crust had been built by the end of Archean and the large fracture systems formed in the NORTH CHINA CRATON, Hoeever their original trends are difficult to be measured at present.
