Paleo-Tethys system and accretionary orogen in the Tibet Plateau
Paleo-Tethys system and accretionary orogen in the Tibet Plateau
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作者：
Xu Zhi
青藏高原古特提斯系是在多洋盆、微地形（陆缘陆块）、岛弧、俯冲、碰撞等环境下形成的。它的建筑包括四个蛇绿岩或蛇绿混杂岩带代表古特提斯洋地壳遗迹（南昆仑-阿尼玛卿蛇绿岩带、金沙江-哀牢山-松马蛇绿岩带、中羌塘-澜沧江-昌宁孟连蛇绿岩带和松多蛇绿岩带）、五条火山岩浆岛弧（布尔汉提弧、义敦弧、江达-绿春弧、东大山-云县弧、左贡-临沧弧-碰撞）、四种地体（松潘-甘孜地体、北羌塘-昌都-思茅地体和南羌塘-保山-锡布马苏地体）三条高压-超高压变质带（得荣高压带、龙木左-双湖高压带、松多超高压-高压带）以及5个弧前增生楔（AW）或增生杂岩带（西秦岭AW、巴彦哈尔-松潘岗泽AW、金沙江AW、双湖-聂荣-吉塘-临沧AW和松垛AW）。在青藏高原古特提斯复合造山带中广泛记录了由多个古特提斯俯冲-增生杂岩构成的俯冲-增生造山带。古特提斯俯冲-增生杂岩包括强烈变形的弧前沉积增生楔和蛇绿岩、高压变质岩、岛弧岩浆岩等外来岩块，反映了古特提斯洋俯冲过程中活动大陆边缘的地壳增生。
The Paleo-Tethys system in the Tibet Plateau formed under environment of multi-ocean basins,micro-terrains ( ribben continents) ,island arcs,subductions and collisions. Its architectures include four ophiolite or ophiolitic melange belts representing Paleo-Tethysoceanic crustal relics ( South Kunlun-Animaqen ophiolite zone,Jinshajiang-Ailaoshan-Songma ophiolite zone,Central Qiangtang-Lancangjiang-Changning Menglian ophiolite zone and Songduo ophiolite zone ) , five volcanic magmatic island arcs ( Bulhanbuda arc,Yidun arc,Jiangda-Luchun arc,Dongdashan-Yunxian arc,Zuogong-Lincang arc-collision) ,four terrains ( Songpan-Ganze terrain,North Qiangtang-Changdu-Simao terrain and South Qiangtang-Baoshan-Sibumasu terrain) ,three HP-UHP metamorphic belts ( Derong HP belt,Longmu Tso-Shuanghu HP belt,Songduo UHP-HP belt) ,as well as five forearc accretionary wedges ( AW) or accretionary complex belts ( West Qinling AW,Bayan Har-Songpan Gangze AW,Jinshajiang AW,Shuanghu-Nierong -Jitang-Lincang AW and Songduo AW) . The subduction-accretionary orogens constructed by multi Paleo-Tethys subductions-accretional complexes,were wide spreadly recorded in the Paleo-Tethys composive orogeinic belts of the Tibet Plateau. The Paleo-Tethys subduction-accretional complexes including arc front sediment accretional wedges of strong deformation and exotic blocks composed of ophiolites,HP metamorphic rocks and island arc magmatic rocks,which indicate crustal accretion of active continental marginduring Paleo-tethysoceanic subduction processes.