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冈底斯花岗岩带是沿雅鲁藏布江北侧近东西向展布的一条长约2 500 km、宽100~300 km的巨型岩浆岩带。在阿里冈底斯山主峰岗仁波齐峰附近,冈底斯花岗岩体受到多期断裂活动的影响,特别受喜马拉雅大反向断裂和喀喇昆仑断裂活动的改造,造成断裂和岩体的关系出现很多复杂的情况,一些研究者把在北阿伊拉日居山分布的32~25 Ma的花岗岩作为喀喇昆仑断裂活动引起的同构造花岗岩,并把此年龄段归结为断层活动年龄,从而引起了极大的争论。本文的锆石u-Pb年龄指示了岗仁波齐峰地区的冈底斯花岗岩是由110 Ma、60 Ma和50 Ma的3期花岗岩组成,而韧性剪切带内的锆石年龄与附近未变形岩石内的锆石年龄一致,表明锆石的形态并未受到断裂活动的影响。韧性剪切带内云母的氩氩年龄为12 Ma左右,而周围未变形花岗岩的云母氩氩年龄在60~50 Ma左右,由此表明喀喇昆仑断裂在岗仁波齐峰地区是12 Ma开始活动的。由于研究区内韧性剪切带中的变形花岗岩并没有记录32~25 Ma这期热事件,由此排除了断裂在狮泉河—门士一线是32~25 Ma开始活动的可能性。
The Gangdese granite belt is a giant magmatic belt about 2 500 km long and 100-300 km wide spread in the east-west direction on the northern side of the Yarlung Zangbo River. The Gangdise granite body was affected by multi-phase fault activities near the Gangpok Peak, the main peak of the Aligunidas Gang, and was especially affected by the major Himalayan and Karakoram faults, resulting in the relationship between faults and rock mass A lot of complicated situations have appeared. Some researchers consider granite from 32 to 25 Ma distributed in Habitat of North Ailah as the syntectonic granite caused by the Karakorum fault activity, and attribute this age group to the age of fault activity. Aroused great controversy. The zircon u-Pb ages of this paper indicate that the Gangdese granites in the Boqi Qimian area consist of three granites of 110 Ma, 60 Ma and 50 Ma, while zircon ages in ductile shear zones The age of the zircons in the deformed rocks is consistent, indicating that the zircon morphology has not been affected by the fault activity. The Argon-Argon ages of the mica in the ductile shear zone are about 12 Ma, whereas the Argon-Argon ages of the unconformable granites in the surrounding are around 60 to 50 Ma, indicating that the Karakorum Fault started its activity at 12 Ma in the Junggar Junggar area of. Since the deformed granites in the ductile shear zone in the study area did not record the 32-25 Ma thermal event, the possibility of the fault starting from 32-25 Ma in the Shiquanhe-Mencde line was excluded.