青藏高原羌塘中部果干加年山二叠纪蛇绿岩岩石学和同位素定年

Petrology and geochronology of Guoganjianianshan Permian ophiolite in central Qiangtang，Qinghai-Tibet Plateau，China

摘要: 果干加年山二叠纪蛇绿岩是龙木错-双湖板块缝合带近期的新发现。通过详细的野外地质调查，查明了果干加年山地区二叠纪蛇绿岩出露规模较大，主要由堆晶辉长岩、基性岩墙群、玄武岩等组成。蛇绿岩辉长岩墙获得SIMS锆石年龄272.9Ma±1.8Ma，时代为早二叠世。果干加年山二叠纪蛇绿岩记录了二叠纪早期冈瓦纳大陆北缘发生了一次规模较大的构造事件，为探讨和建立古特提斯洋构造演化的时空模型提供了重要信息。

Abstract: Guoganjianianshan Permian ophiolite is an important discovery in Longmu Co-Shuanghu plate suture zone recently. According to detailed field geological investigation, we found that Guoganjianianshan Permian ophiolite outcroped extensively and included cumulate gabbro, mafic dyke swarms and basalt. In this paper, SIMS U-Pb dating was carried on the zircons of the gabbro dyke of Guoganjianianshan ophiolite. The dating results show that this ophiolite was fromed in Early Permian (272.9±1.8 Ma), which means that a great tectonic event happened in Early Permian. All the research results above have great significance in exploring and establishing the tectonic evolution space-time model of Paleo-Tethys ocean.