东昆仑造山带乌妥地区构造特征及其构造演化分析

Tectonic Characteristics and Evolution Analysis in Wutuo Area in East Kunlun Orogenic Belt

东昆仑乌妥地区在大地构造位置上跨东昆仑弧盆系北昆仑岩浆弧和东昆仑南坡俯冲增生杂岩带,该文对其内发育的不同时期、不同层次的断裂、韧性剪切带和褶皱等构造行迹进行了研究,从局部特征推演至整体特征,达到对研究区构造演化及变质变形的再认识。结合沉积建造、岩浆活动、变质事件、同位素年龄值及区域资料等,确定各构造群落形成的相对时代,进而比较合理地建立起测区的构造变形序列,认为区内自吕梁期-燕山期-喜山期,至少经历了7期12世代的构造变形,期间任一时期构造体制的变更,造山作用类型的变化、盆地类型的转化,都遵循伸展和压缩交替进行这一普遍的地壳演化规律。将东昆仑造山带乌妥地区的构造演化划分为古元古代基底的形成阶段、多旋回的洋陆转换阶段、陆内造山阶段及高原隆升阶段。

Wutuo area in east Kunlun area goes across north Kunlun arc basin system and southeast Kunlun magmat-ic arc subduction accretionary complex in east Kunlun. In this paper,different developing stages,fractures in dif-ferent levels,ductile shear zones and lolds have been studied. Inference Irom local feature to the overall characteris-tics has been carried out. Tectonic evolution and metamorphic deformation research have been recognized again. Combining with the sedimentary formation,magmatic activity and metamorphism,isotope age values and regional data,relative age formed in different tectonic community has been determined, and the tectonic deformation se-quence of the study area has been reasonably established. During Lvliang Yanshan Himalayan tectonic period, this area has experienced at least seven periods and twelve generations deformation. Tectonic regime change in any period,change of orogenic types and transformation of basin types all follow the extension and compression alternate evolution of this general crust. The tectonic evolution of the eastern Kunlun orogenic belt is divided into Paleoprot- erozoic basement,multi cycle ocean continent conversion stage, the intra continental orogenic stage and the plateau uplift stage.