The row echelon granite aplite veined belt extending over one hundred kilometers are developed between the Kunlun Mountain Pass-Gander fault and the Bayan Haran central fault in northern Tibetan Plateau,and most of them are NW-trending,with a few being SN-trending.Based on an analysis of the macroscopic and microscopic characteristics of the row echelon granite aplite veins,as well as the LA-ICP-MS zircon U-Pb dating data for the SN-trending(224.7 ± 0.64 Ma) and NW-trending(220.5 ± 1.1 Ma) granite aplite veins,it is considered that the granite aplite veins are the products of Indosinian Movement,and they were formed in the oblique subduction of the Hoh Xil-Bayan Har terrane beneath the East Kunlun terrane in early Indosinian.The syntectonic granite aplite veins were injected along the "X" conjugate shear joints in the NW(118°) and the SN (2°) direction in the footwall (south section) of the Kunlun Mountain Pass-Gander overthrust fault.The principal compressive stress direction is revealed by the distribution direction of two groups of "X" type conjugate shear joints,which is NW(118°) to the SN(2°).The left order row echelon joints suggest that they are controlled by dextral strike-slip.The earliest formation time of granite aplite veins(224.7 ± 0.64 Ma)represents the time of subduction and strike-slip event,which is also the formation time of the Kunlun Mountain Pass-Gander fault.%在青藏高原北部昆仑山口-甘德断裂与巴颜喀拉山中央断裂之间发育延伸超过100 km的呈雁列排列的花岗细晶岩脉带,这些花岗细晶岩脉走向多为北西向(118°),少量呈南北向(2°).通过对其宏、微观特征分析研究,并结合在这两组花岗细晶岩脉中分别采获的224.7±0.64 Ma(南北向)与220.5±1.1 Ma(北西向)的锆石LA-ICP-MSU-Pb同位素年龄数据,指出这些花岗细晶岩脉是印支运动的产物,是早印支期可可西里-巴颜喀拉地块向东昆仑地块斜向俯冲过程中,岩浆沿着昆仑山口-甘德北西向冲掩断层下盘(南盘)形成的北西向与南北向两组“X”型共轭剪节理贯入形成的同构造花岗细晶岩脉.两组“X”型共轭剪节理的展布方向揭示了印支运动的主压应力方向,即NNW-SSE向;北西向雁列排列的节理反映其受右行走滑作用控制的特点;花岗细晶岩脉形成的最早时间(224.7±0.64 Ma)代表了这次俯冲走滑事件的时间,也即昆仑山口-甘德断裂的形成时间.
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