【作者】 陈虹；

【导师】 杨兴科；

【作者基本信息】 长安大学 ， 构造地质学， 2007， 硕士

【摘要】 迄今为止,对新疆天山地壳结构与构造演化已经有许多论述,受交通条件的限制,研究区内的构造演化研究多以交通条件较好的独-库公路等专家路线为主,且存在较大的争议。研究区位于东西天山的交汇部位,通过新疆自治区两轮1:5万区域地质矿产调查和填图,历经四年多,在收集大量野外及室内地质资料和数据的基础上,较全面的判断研究区内各构造单元的构造环境及其在构造演化中的意义,并结合天山构造带区域构造演化特征,更具体、更全面的论述西天山东段阿拉沟一带的构造演化特征,从而为东、西天山的构造演化研究提供有一定的指导意义。研究区位于西天山东段,处于哈萨克斯坦-准噶尔板块与塔里木板块的交接部位。冰达坂-夏热嘎断裂呈北西西向贯穿研究区,根据地质与地球物理资料分析,该断裂具有早期向北推覆,后期演变为向南逆冲的性质,其南侧的中天山构造分区划归博罗科努古生代复合岛弧带;以北的北天山构造分区以向北逆冲的红五月桥-苏木特达坂断裂为界,北部划归博格达晚古生代弧后裂陷盆地;南部划归依连哈比尔尕晚古生代沟弧带和大南湖晚古生代岛弧带,中间以具有滑脱性质的苏木特西-阿拉沟断裂为界。结合野外宏观和室内显微构造及岩组测试等研究将冰达坂-夏热嘎韧性剪切带划分为脆韧性挤压剪切-韧性挤压剪切-走滑韧脆性剪切-脆性变形四个演化阶段。通过野外调研及室内岩石学、岩石地球化学、遥感地质学及其构造变形特征的综合对比研究,博罗科努古生代复合岛弧带火山岩显示为岛弧环境,多期岩浆侵入体体现了由碰撞前陆缘弧向同碰撞火山弧演化的进程,并且可能存在变质核杂岩构造体系;依连哈比尔尕晚古生代沟弧带内出露的天格尔岩组显示洋壳火山弧环境,其后侵入的石炭纪花岗岩显示大洋岛弧环境构造岩浆产物,沟-弧环境较明显;大南湖晚古生代岛弧带小热泉子组显示了陆壳岛弧环境;博格达晚古生代弧后裂陷盆地石炭纪为弧后盆地挤压机制,二叠纪变化为断陷上叠构造盆地,反映研究区碰撞造山作用主要发生在晚石炭世和二叠纪之间,中生代的断陷盆地为后期陆内拉张伸展环境。结合前人对天山造山带构造演化研究的成果,将研究区的构造演化划分为四个阶段:晚古生代以前北天山洋形成-发展-闭合演化阶段、泥盆纪-石炭纪有限洋盆拉张-碰撞造山阶段、二叠纪-中生代造山后陆内伸展断陷阶段、新生代陆内差异沉降阶段。更多还原

【Abstract】 At present, although there are already many discussions for the crust fexture and tectonic evolution of Tianshan, Xinjiang, the research of the tectonic evolution for the study area were mainly on the specialist routes with convenient transit like the Du-Ku road, which is limited by the transit, and there are some disputes. The study region locates the connected position between the East and west Tianshan, through two samsaras 1:50000 regional geologic mineral examination and mapping from Xinjiang Autonomous Region, the tectonic environments and the importance for the tectonic evolution of the tectonic elements in the study region are comprehensively judged depend on gathering amount of field and interior geologic materials and dates. The aim is to discuss the partly regional tectonic evolution in Tianshan orogenic belt more concrete and comprehensive by combining the regional tectonic evolution of Tianshan tectonic belt, and it will guide the research of the connection of the East and West Tianshan.The study region locates on the combinative region of Kazakhstan-Junggar Plate and Tarim Plate, which belongs to the east of the West Tianshan. Bindaban-Xiarega Fault runs through this area in northwest-west orientation, it has the change from northward nappe to southward overthrust depended on the geologic and geophysical datas, the south of the fault is the Paleozoic composite arc belt of Boluokenu belongs to The Mid Tianshan district; and the north of the fault belongs to the North Tianshan tectonic district, which is futherly divided into the Upper Paleozoic trench-arc belt of Yilianhabierga and the Upper Paleozoic arc belt of Dananhu in the south divided by the Sumutexi-Alagou fault which is detachment fault and the Upper Paleozoic back-arc taphrogenic basin of Bogeda in the north by the Hongwuyueqiao -Sumutedaban fault, which is northward overthrust. Depending on the research on the field and the microstructure and fabric analysis in indoors, the Bindaban-Xiarega Ductile shear zone is divided into four main stages: brittle-ductile compressional shear - ductile compressional shear - ductile-brittle strike-slip shear - brittle deformation.Using the accurate tectonic environmental judgment through the comprehensive contrast of the petrologic, lithogeochemical, remote sensing geology and deformational characteristics in indoors and macroscopic characteristics in field on the tectonic elements, the volcanic rock in the Paleozoic composite arc belt of Boluokenu indicate the island arc environment, the multiple magma intrusion embodies the progress of the procollision continental-margin arc turn into syncollision volcanic arc, and there are one Metamorphic Core Complex may exist at Upper Proterozoic period in the Mid Tianshan; the Tiangeer formation in the Upper Paleozoic trench-arc belt of Yilianhabierga indicate the oceanic volcanic-arc environment, the later intrusional Carboniferous granite is the tectonic magmatic product of the oceanic island-arc, and constitute a complete trench-arc system; the Xiaorequanzi formation in the Upper Paleozoic arc belt of Dananhu display the continental crust island-arc environment; the Upper Paleozoic back-arc taphrogenic basin of Bogeda is compressional back-arc basin in Carboniferous, and turn into downfaulted tectonic basin in Permian, it reflect the collisional orogeny mainly occurred among the Upper Carboniferous and the Permian, and the downfaulted basin in Mesozonic Era is intracontinent pull-expansion extensional environment.Combining the achievement of the tectonic evolutional research in the past, the tectonic evolution in the research region is divided into four main stages: the formation-development-close of the North Tianshan Ocean evolution stage at Proterozoic - Lower Paleozoic; the limted oceanic basin pull-expansion to collision orogeny stage at Devonian-Carboniferous; the intracontinent extensional taphrogenic stage at Permian-Mesozoic Era and the intracontinent differential subsidence stage at Cenozoic.更多还原