高级检索
    吴才来, 雷敏, 张昕, 陈红杰, 吴迪, 李天啸. 南阿尔金花岗岩锆石Lu-Hf同位素特征及岩石成因[J]. 中国地质, 2016, 43(6): 1853-1883. DOI: 10.12029/gc20160602
    引用本文: 吴才来, 雷敏, 张昕, 陈红杰, 吴迪, 李天啸. 南阿尔金花岗岩锆石Lu-Hf同位素特征及岩石成因[J]. 中国地质, 2016, 43(6): 1853-1883. DOI: 10.12029/gc20160602
    WU Cai-lai, LEI Min, ZHANG Xin, CHEN Hong-jie, WU Di, LI Tian-xiao. Petrogenesis and zircon Lu-Hf isotopic characteristics of the granites from the southern Altun area, Northwest China[J]. GEOLOGY IN CHINA, 2016, 43(6): 1853-1883. DOI: 10.12029/gc20160602
    Citation: WU Cai-lai, LEI Min, ZHANG Xin, CHEN Hong-jie, WU Di, LI Tian-xiao. Petrogenesis and zircon Lu-Hf isotopic characteristics of the granites from the southern Altun area, Northwest China[J]. GEOLOGY IN CHINA, 2016, 43(6): 1853-1883. DOI: 10.12029/gc20160602

    南阿尔金花岗岩锆石Lu-Hf同位素特征及岩石成因

    Petrogenesis and zircon Lu-Hf isotopic characteristics of the granites from the southern Altun area, Northwest China

    • 摘要: 在以往工作的基础上,结合本文的岩石地球化学研究,将南阿尔金花岗岩划分为5期,第1期花岗岩组合为石英闪长岩+花岗闪长岩+二长花岗岩,具有I型花岗岩的属性,时代>460 Ma;第2期花岗岩组合为花岗闪长岩+二长花岗岩+正长花岗岩,也具有I型花岗岩的特征,时代为435~450 Ma;第3期花岗岩组合为二长花岗岩+正长花岗岩+碱长花岗岩,具有A型花岗岩的属性,时代为385~411 Ma;第4期花岗岩组合为花岗闪长岩+二长花岗岩,时代为343~352 Ma,具有S型花岗岩的地球化学属性;第5期花岗岩组合为石英闪长岩+二长花岗岩+正长花岗岩,具有I型花岗岩的地球化学特征,时代为265 Ma。各期花岗岩锆石Lu-Hf同位素分析表明,εHft)值大多数为正值,少数继承性锆石为负值,反映了它们的源岩以新生地壳为主,同时,也混有少量的古大陆壳的成分。根据年代学和岩石地球化学研究结果,结合区域地质特征,我们认为第1期(465~469 Ma)花岗岩浆活动可能与洋壳的俯冲作用有关;第2期(435~450 Ma)岩浆活动可能是碰撞后环境;第3期(404~411 Ma)岩浆活动可能与板块碰撞后造山带块体均衡调整、伸展有关,第4期(343~352 Ma)、第5期(265 Ma)岩浆活动可能与造山带深部块体的拆沉作用有关。

       

      Abstract: On the basis of previous studies in conjunction with granite dating and geochemical study results in this paper, the South Altun granite can be divided into five episodes:episode 1, characterized by the granite association of quartz diorite+granodiorite+monzogranite, with affinities of I-type granite and an age of >460 Ma; episode 2, characterized by the granite association of granodiorite+monzogranite+syenogranite, with geochemical affinities of I-type granite and an age of 435-450 Ma; episode 3, characterized by the granite association of monzogranite+syenogranite+alkali feldspar granite, with affinities of A-type granite and an age of 385-411 Ma; episode 4, characterized by the granite association of granodiorite+monzogranite with an age of 343-352 Ma, with geochemical affinities of S-type granite; and episode 5, characterized by the granite association of quartz diorite+monzogranite+syenogranite, with geochemical affinities of I-type granite and an age of 265 Ma. Zircon Lu-Hf isotope analysis of granite in various episodes showed that εHf(t) values are positive in most cases and negative for a small number of inherited zircons, indicating that their source rocks were mainly juvenile crust mixed with a minor amount of ancient continental components. Based on the results of the above studies in conjunction with regional geological characteristics, it is considered that episode-1 granitic magma activity might be related to the subduction of oceanic crust, episode-2 magma activity might belong to post-collisional magma activity, episode-3 magma activity might be related to the isostatic adjustment of orogen blocks after plate collision, and episode-4 and episode-5 magma activity might be related to the delamination of deep blocks under the southern Altun orogen.

       

    /

    返回文章
    返回