西藏亚贵拉矿区两期岩体LA-ICP-MS锆石U-Pb定年及地质意义  

LA-ICP-MS zircon U-Pb dating of two types of porphyry in the Yaguila mining area,Tibet

作　　者：黄克贤[1,2] 郑远川[2] 张松[1,2] 李为[1,2] 孙清钟[2] 李秋耘[1,2] 梁维[1,2] 付强[1,2] 侯增谦[2] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质科学院地质研究所,北京100037

出　　处：《岩石矿物学杂志》2012年第3期348-360,共13页Acta Petrologica et Mineralogica

基　　金：国家重点基础研究发展计划资助项目(973计划;2011CB403100);中国地质调查局地质调查项目(1212011121253);国家青年科学基金资助项目(41102033)

摘　　要：亚贵拉Pb-Zn-Ag矿床是冈底斯北侧Pb-Zn多金属成矿带内的一个大型矿床。钻孔编录发现,亚贵拉矿区内棕红色花岗斑岩和灰白色石英斑岩均被大量的含硫化物石英脉穿切。同时,与这两套斑岩直接接触的灰岩地层内同样伴有强烈的硫化物矿化和矽卡岩化。本文采用LA-ICP-MS锆石U-Pb测年技术,对矿区含矿棕红色花岗斑岩和灰白色石英斑岩分别进行了年代学研究,得到两者锆石的加权平均年龄分别为132.1±1 Ma和62.4±0.6 Ma。在钻孔编录过程中未发现典型沉积喷流成因的矿体,而绝大部分矿体以含有大量矽卡岩矿物为特征,表明亚贵拉Pb-Zn-Ag多金属矿床应主要受岩浆热液控制。锆石U-Pb定年结果显示,该矿区首先经历了早白垩世与棕红色花岗斑岩有关的岩浆事件,然后于古新世又受到了与灰白色石英斑岩有关的含矿热液富集沉淀。结合已有研究资料分析可知,冈底斯北带的成矿作用从白垩纪一直持续到中新世,且均以Pb-Zn-Ag等贱金属矿化为特征,显示冈底斯北带古老基底对矿化金属类型的强烈控制。The Yaguila Pb-Zn-Ag deposit is a large-size ore deposit on the north margin of Gangdise.Some experts considered that the ore deposit was formed by marine jet flow superimposed by magmatism,whereas others thought that it was formed only by magmatism.Detailed drill hole investigations into the Yaguila ore deposit show that both the light brown porphyry and the gray quartz porphyry contain a large volume of ore-bearing stockwork quartz veins.Meanwhile,large amounts of massive ores are developed along the contact zone between the two types of porphyries and limestone.Therefore,both the light brown porphyry and the gray porphyry must have played an important role in mineralization of the Yaguila ore deposit.In the present study,the authors analyzed zircon U-Pb ages for the two kinds of porphyries by using LA-ICP-MS.Mean ages of the concor

关 键 词：矽卡岩矿床 锆石U-PB定年 成矿作用 亚贵拉 西藏 

分 类 号：P597.3[天文地球—地球化学]