西藏狮泉河地区纳日组火山岩地球化学特征、锆石U-Pb年龄及构造意义  

Geochemical Characteristics,Zircon U-Pb Age and Tectonic Significance of Volcanic Rocks of the Nari Formation in the Shiquanhe Area of XiZang

作　　者：康晓波 李宏伟 代克刚 赵洪飞 唐建科 KANG Xiaobo;LI Hongwei;DAI Kegang;ZHAO Hongfei;TANG Jianke(The Fifth Geological Brigade of Geological and Mineral Exploration and Development Bureau of Tibet Autonomous Region,Lhasa 850000,China)

机构地区：[1]西藏自治区地质矿产勘查开发局第五地质大队,西藏拉萨850000

出　　处：《四川有色金属》2024年第3期50-54,共5页Sichuan Nonferrous Metals

基　　金：班公湖-怒江成矿带铜多金属矿资源基地调查《西藏日土县约拉山1/5万四幅区域地质调查》(DD20160026)。

摘　　要：狮泉河中生代纳日组火山岩位于拉萨地块西端,雅鲁藏布缝合带南端和班公湖-怒江缝合带南北向缩短尖灭的西侧关键部位。通过对狮泉河地区的中生代纳日组火山岩的年代学与地球化学研究,表明其为一套酸性火山碎屑岩夹火山熔岩,属高钾钙碱性系列;具火山弧环境特征,并形成于挤压构造环境,源岩物质多来可能来自壳幔混源。纳日组流纹质凝灰岩LA-ICP-MS锆石U-Pb年龄为153±1.1Ma,结合前人研究成果,表明印度与亚洲大陆的碰撞具有西早东晚的特点[1-5]。The Mesozoic Nari Formation volcanic rocks in the Shiquanhe area are situated in the western part of the Lhasa block,within the southern segment of the Bangong-Nujiang suture zone,and occupy a pivotal position in the south-north contraction and uplift of the Bangong Lake-Nujiang suture zone.The chronology and geochemistry analysis of these volcanic rocks reveal their composition as acidic volcaniclastic rocks with lava flows,belonging to the high potassium calc-alkaline series.They exhibit typical characteristics of a volcanic arc environment and were formed under compressional tectonic conditions,potentially sourced from a mixture of crustal and mantle materials.The LAICP-MS zircon U-Pb dating indicates an age of 153±1.1 Ma for rhyolite tuff within the Nari Formation.Combined with previous research findings,it is evident that India's collision with Asia exhibits an early westward movement followed by later eastward motion.

关 键 词：纳日组 火山岩 地球化学 年代学 构造环境 

分 类 号：P618[天文地球—矿床学]