摘要
标明日期的虾 U-Pb 从 Niuxinshan 片麻岩的花岗石和 Leigongshan 在锆石上被执行在北方 Qilian orogen 的片麻岩的吨子盐， NW 中国。结果分别地产出 776+-10 妈和 774 +-23 妈的加权的平均 ~(206 )Pb/~(238 ) U 年龄。Igneousmorphology，摆动的 zonings，和为这些锆石的相对高的 Th/U 比率建议 magmaticorigin。这些年龄作为岩浆炮兵阵地预定并且因此代表 aNeoproterozoic (约 775 妈) 被解释在北方 Qilian 区域的 magmatic 事件。thismagmatism 可能与超级大陆 Rodinia 的决裂有关，这被建议。这发现，和 750 ～ 800 妈的类似的年龄为南方中央的 Qilian 和北方 Qaidam 的附近的岩层报导了，具有到在韦斯特中国的 Rodinia 进化的理解的意义。
SHRIMP U-Pb dating was carried out on zircons from the Niuxinshan gneissic granite and the Leigongshan gneissic tonalite in the North Qilian orogen, NW China. The results yield weighted averaged ^206Pb/^238U ages of 776±10 Ma and 774±23 Ma respectively. Igneous morphology, oscillatory zonings, and relatively high Th/U ratios for these zircons suggest magmatic origin. These ages are interpreted as timing of magma emplacement and thus representing a Neoproterozoic （～775 Ma） magmatic event in the North Qilian area. It is suggested that this magmatism is probably related to breakup of the supercontinent Rodinia. This finding, together with the similar ages of 750 to 800 Ma reported for neighboring terranes of South-central Qilian and North Qaidam, is of significance to understanding of the Rodinia evolution in West China.
关键词
岩浆
造山带
SHRIMP
锆石
年代测定
North QUian orogen, zircon U-Pb age, Neoproterozoic magmatism, Rodinia breakup.
