中天山巴伦台南缘一带侵入岩的确定及构造意义

The Intrusive Rocks' Identification and Tectonic Significance of Southern Margin of Baluntai Area in Central Tianshan Mountain

中天山巴伦台南缘一带主要出露一套基性-中酸性侵入岩,岩石组合为片麻状闪长岩、片麻状石英闪长岩、片麻状花岗闪长岩、片麻状黑云母花岗岩。通过野外宏观地质观察、岩石学、岩石地球化学研究,结合岩石同位素定年和前人的年代学资料认为,该区侵入岩形成时代为晚奥陶—早志留世,形成构造环境是板块碰撞前活动陆缘弧环境,当时的构造应力场为NS向挤压应力阶段,岩体具强变质强变形特征,岩浆物质来源于碰撞造山前期的壳幔混源岩浆和同碰撞期的上地壳重熔改造岩浆。该区侵入岩标志着南天山洋在早古生代中晚期开始向中天山地块下俯冲聚敛。

In southern margin of Baluntai area mainly exposed a set of basic- acidic intrusive rocks,whichisconsists of gneissic diorite,gneissic quartz diorite,gneissic granodiorite,gneissic biotite granite,according tosystematic macroscopic geological field observation、petrographic、geochemical studies,combined with Rock isotopic dating methods and previous chronological data,which believes that the intrusive rocks in this area is formed in the middle Ordovician—middle Silurian era,and its forming tectonic environment is active continental margin arc environment before plate collision,tectonic stress field at the time is the north-south compressional stress phase,and the features in place with strong deformation and strong Metamorphism,rock with strong.Magmatic material from the pre-collision orogenic crust-mantle mixed source magma and the crust remelting magma with collision reconstruction period.Intrusive rocks in this area represents the subduction process that the southern Tianshan ocean in the late Paleozoic began to amass under the central Tianshan Plate.