内蒙古西乌旗南部晚古生代侵入岩年代学、地球化学特征及地质意义

发布时间：2018-07-31 09:31

【摘要】：为探讨兴蒙造山带南蒙古陆块南缘晚古生代的构造演化,对出露于西乌旗南部石英闪长岩、花岗闪长岩和黑云母花岗岩开展了详细的年代学、岩石地球化学及Hf同位素特征研究.结果表明:石英闪长岩、花岗闪长岩和黑云母花岗岩分别形成于330±2Ma、274±1Ma及271±1Ma~282±1Ma.石英闪长岩属高镁闪长岩/安山岩类(HMA),与俯冲洋壳板片上部地幔楔中地幔橄榄岩的熔融作用有关,而花岗闪长岩及黑云母花岗岩的源区可能与新生地壳的部分熔融有关.结合区域成果,推测西乌旗南部晚古生代侵入岩均形成于古亚洲洋向北侧南蒙古陆块持续俯冲的阶段,早石炭世石英闪长岩属活动大陆边缘弧岩浆活动,早二叠世花岗闪长岩和黑云母花岗岩则是俯冲过程中短暂弧后伸展阶段的产物.
[Abstract]:In order to explore the late Paleozoic tectonic evolution of the southern margin of the southern Mongolia continental block in the Xingmeng orogenic belt, the detailed chronology, rock geochemistry and Hf isotopic characteristics of the quartz diorite, granodiorite and biotite granite in the southern part of the West Wu banner were studied. The results showed that the quartz diorite, the granodiorite and the black mica granite were formed respectively. 330 + 2Ma, 274 + 1Ma and 271 + 1Ma~282 + 1Ma. quartz diorite belongs to the high magnesium diorite / andesite class (HMA), which is related to the melting of mantle peridotite in the upper mantle wedge of subducted oceanic crust, and the source area of granodiorite and biotite granite may be related to the partial melting of the new crust. The late Paleozoic intrusive rocks in the south are all formed in the continuous subduction stage of the southern Mongolia continental block in the paleo Asian Ocean. The Early Carboniferous quartz diorite belongs to the active continental margin arc magmatism, and the early Permian granodiorite and the black mica granite are the products of the brief post arc extension stage during the subduction process.
【作者单位】：中国地质大学地球科学与资源学院;江西省地质矿产勘查开发局物化探大队;
【基金】：中国地质调查局地质调查项目(No.1212011085490)
【分类号】：P588.12

【相似文献】