西藏狮泉河蛇绿混杂岩带——一个新的多岛弧盆系统的厘定及意义  

The Shiquan River ophiolitic mélange zone in Xizang: The delineation and significance of a new archipelagic are-basin system

作　　者：郑有业 许荣科 何来信[1] 龚全胜[2] 茨邛 

机构地区：[1]西藏地质调查院 [2]甘肃地质调查院,甘肃兰州730050

出　　处：《沉积与特提斯地质》2004年第1期13-20,共8页Sedimentary Geology and Tethyan Geology

基　　金：区域地质调查项目 (2 0 0 2 1 30 0 0 0 0 9)

摘　　要：狮泉河蛇绿混杂岩带的结构、性质、形成时间及与班 怒带的时空演化关系是青藏高原大地构造划分中亟待解决的问题。通过系统的地质调查工作 ,证实狮泉河带内存在完整的蛇绿岩带 ,并首次将其划分为 4个蛇绿岩亚带 ,相互之间由 3个呈平行分布的岛弧链分隔 ,从而构成一个早白垩世的多岛弧盆系统。狮泉河带闭合过程为岛弧造山过程 ,俯冲极向主要向北 ,构成冈底斯 腾冲陆块和喀喇昆仑 南羌塘 左贡陆块之间的晚燕山期结合带 ;它与班 怒带在时间上具有继承性 ,空间上由北向南迁移 ,并部分重叠 ,反映了由班 怒带向狮泉河带的转化是一种接力式的。上述发现对青藏高原大地构造单元划分。The key problem in the geotectonic division of the Qinghai-Xizang Plateau includes the examination of structures, nature, ages and spatio-temporal relations to the Bangong-Nujiang zone. There exists a complete ophiolite zone in the Shiquan River zone, including four ophiolite subzones. These ophiolite subzones are (arranged) to be separated by three parallel island chains, constituting an Early Cretaceous archipelagic (arc)-(basin) (system). The closure processes represent the (island)-(arc) mountain-building processes in the Shiquan River zone. The subduction polarity is directed chiefly to the north, with a late Yanshanian suture zone intermediate (between) the (Gangdise)-(Tengchong) and (Karakorum)-(South) (Qiangtang)-(Zogang) continental masses, all of which were evolved from the (Bangong)-(Nujiang) zone. The transition from the (Bangong)-(Nujiang) zone to the Shiquan River zone (behaved) just like a way of relay race. The findings cited above may be significant to the division of the tectonic (units) of the (Qinghai)-(Xizang) Plateau and the examination of the tectonic evolution of the (Neo)-(Tethys).

关 键 词：狮泉河 蛇绿混杂岩 多岛弧 板块结合带 西藏 

分 类 号：P542.4[天文地球—构造地质学]