祁漫塔格东段晚三叠世—早侏罗世花岗岩LA-ICP-MS锆石U-Pb年龄及其地质意义  

LA-ICP-MS zircon U-Pb dating of the Late Triassic-Early Jurassic granites in the eastern part of Qimantag area and its geological significance

作　　者：赵洪菊[1,2] 陈静[1,2] 王秉璋[1,2] 陈发彬[1,2] 王国良[1,2] 宋泰忠[1,2] 

机构地区：[1]青海省地质调查院,青海西宁810012 [2]青海省青藏高原北部地质过程与矿产资源重点实验室,青海西宁810012

出　　处：《地质通报》2017年第6期1001-1009,共9页Geological Bulletin of China

基　　金：中国地质调查局项目<柴达木周缘及邻区成矿带地质矿产调查评价专项>(编号:1212010818048);青海省地质勘查基金项目<青海省格尔木市拉陵灶火铜多金属矿整装勘查区找矿部署研究>(编号:青国土资矿[2015]83)

摘　　要：祁漫塔格东段拉陵高里河地区晚三叠世—早侏罗世花岗岩组合为高SiO_2(72.18%~76.55%)、高K_2O(4.08%~5.32%)的碱性花岗岩组合,具有明显的负Eu异常(δEu平均值为0.28)。岩石组合为二长花岗岩+正长花岗岩,采用LA-ICP-MS技术测得二长花岗岩和正长花岗岩的年龄分别为205.1±1.0Ma和199.5±1.2Ma。该套花岗岩组合与拉陵高里河地区的矽卡岩型多金属矿关系密切,初步确定祁漫塔格地区晚三叠世—早侏罗世花岗岩组合也是一期重要的成矿岩浆建造。The Late Triassic-Early Jurassic granitic assemblage in the eastern part of Qimantag area has high SiO_2 content(72.18%~76.55%), high K_2O content(4.08%~5.32%) and obvious negative Eu anomaly(average σEu value being 0.28). The granitic assemblage is composed of monzogranite and syenogranite, whose ages were precisely redefined by the LA-ICP-MS zircon U-Pb method, being 205.1±1.0Ma and 199.5±1.2Ma respectively. This granitic assemblage has close relationship with skarn-type polymetallic deposits in Lalinggaoli area. Therefore, the authors preliminarily hold that the Late Triassic-Early Jurassic granitic assemblage is probably an important ore-forming magmatic formation in the eastern part of Qimantag area.

关 键 词：祁漫塔格 花岗岩 晚三叠世—早侏罗世 LA-ICP-MS锆石U-PB年龄 

分 类 号：P534.5[天文地球—古生物学与地层学] P597.3[天文地球—地质学]