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秦岭-大别-苏鲁造山带出露大量中生代岩浆岩,对这些岩浆岩进行精确的锆石U-Pb年代学研究可以为揭示大陆碰撞过程、追溯岩浆源区物质来源提供线索.对出露在西秦岭地区的黄渚关和厂坝花岗岩进行了LA-ICP-MS锆石U-Pb年代学研究和全岩地球化学研究.结果表明,黄渚关花岗岩中心相和边缘相锆石的加权平均年龄分别为(214±1)和(213±3)Ma;厂坝花岗岩的锆石的加权平均年龄为(213±2)Ma.这些年龄年轻于华南陆块与华北陆块碰撞引起超高压变质的年龄225~240Ma,对应于同折返岩浆活动.厂坝花岗岩中存在若干新元古代继承锆石((757±14)Ma),说明其岩浆源区为华南陆块.地球化学上,这两个岩体都富集LILE和LREE、亏损HFSE和HREE,表现出典型的弧岩浆岩的特点.但是,黄渚关花岗岩的主要氧化物之间呈现良好的线性关系,暗示同源岩浆演化的特点;中心相含有大量闪长质微粒包体,暗示岩浆混合的存在.厂坝花岗岩相对高Si和K,低Fe和Mg,且具有较高的Fe*,说明其为岩浆高度演化产物,它的出现预示着秦岭造山带已进入碰撞晚期的伸展拉张演化阶段.因此,黄渚关和厂坝花岗岩是秦岭造山带在碰撞晚期晚三叠世期间华南陆块不同成分地壳物质分别发生部分熔融的产物.
A large number of Mesozoic magmatic rocks are exposed from the Qinling-Dabie-Sulu orogenic belt, and accurate zircon U-Pb dating of these magmatic rocks can provide clues for revealing the continental collision process and tracing the source of magma source materials. LA-ICP-MS zircon U-Pb zircon dating and whole-rock geochemistry were carried out in the Huangzhuiguan and Damba granites in the West Qinling Mountains.The results show that the zircons of the central and marginal zircons of the Huangzhuguan Granite are weighted by The average ages of the zircons from the granite in Changba are (214 ± 1) and (213 ± 3) Ma, respectively. The weighted average ages of the zircons from the granites in the dam are (213 ± 2) Ma. These ages are younger than those caused by the collision between the South China continent and the North China continent, Metamorphic age of 225 ~ 240Ma, corresponding to the same fold reef magmatism. There are a number of Neoproterozoic inherited zircon (757 ± 14 Ma) in the granite of the dam, indicating that the magmatic source area is the South China terrane. Both rocks are enriched in LILE and LREE and depleted in HFSE and HREE, showing typical characteristics of argillaceous rocks. However, there is a good linear relationship between the major oxides of the Huangzhuguan granite, indicating the evolution of Features; center phase contains a large number of dioritic microparticle inclusions, suggesting rock The presence of high-grade magma in the dam shows that the granite in the dam is relatively high in Si and K, low in Fe and Mg and high in Fe *, indicating that it is a highly evolved product of magma and its occurrence indicates that the Qinling orogenic belt has entered the late extension of the collision Therefore, the Huangzhuiguan and Changba granites are the products of partial melting of crustal materials in different components of the southern China continental block during the Late Triassic in the Qinling orogenic belt.