论雅鲁藏布大峡谷地区冈底斯岛弧花岗岩带

The Gangdise island-arc granite zone along the Yarlung Zangbo Grand Canyon, Xizang

摘要: 雅鲁藏布大峡谷北部的冈底斯岛弧花岗岩带可分为若干亚带,但岩浆活动大致可分为两大期次,分别与两次大规模造山活动有关。喜马拉雅造山作用在本区形成大量中新世花岗岩体,分布在离雅鲁藏布结合带较近部位;本区北部大量的早侏罗世至晚白垩世花岗岩,据其空间展布、岩浆活动时间、成因类型和岩石组合特征分析,应与怒江特提斯洋的闭合造山有关,同时说明本次造山作用可能是中生代的一次长期的构造-岩浆活动。

Abstract: The Gangdise island-arc granite zone along the Yarlung Zangbo Grand Canyon, Xizang may be subdivided into several subzones, generally representing tw ophases of magmatism and orogeny in this region. The Him alayan orogeny resulted in the widespread occurrence of the Miocene granitic batholiths nearer to the Yarlung Zangbo suture zone. The Early Jurassic and Late Cretaceous granites in the northern part of the study area should be relevant, in terms of the spatial distribution, timing of magmatic activity and genetic types of the granites, to the Nujiang Ocean closure and orogeny which may represent a long period of tectonism and magm atism during the Mesozoic.