北羌塘查肖玛地区日阿巴亚楼花岗斑岩的年代学、地球化学特征及地质意义  

Geochronology,petrogeochemistry and geological significance of Riabayalou granite porphry in Chaxiaoma area,northern margin of Qiangtang block

作　　者：吴树宽 田滔 李戬 张元 李春斌 吴金宏 WU Shukuan;TIAN Tao;LI Jian;ZHANG Yuan;LI Chunbin;WU Jinhong(No.5 Geological Survey Institute of Qinghai Province,Xining 810000,Qinghai,China)

机构地区：[1]青海省第五地质勘查院,青海西宁810013

出　　处：《矿产勘查》2023年第5期669-678,共10页Mineral Exploration

基　　金：中国地质调查局项目“青海沱沱河地区铅锌矿整装勘查区矿产调查与找矿预测”(121201004000150017-40)资助。

摘　　要：日阿巴亚楼花岗斑岩位于北羌塘北缘查肖玛地区,本文对其进行了锆石U-Pb年代学、全岩地球化学测试。结果表明,锆石U-Pb年龄为(64.46±0.60)Ma,说明岩石形成于早古新世早期。花岗斑岩具有高硅、富碱(K_(2)O+Na_(2)O=6.60%~8.81%),贫MgO、TFe_(2)O_(3)和CaO,为钙碱性准铝—弱过铝质系列。岩石富集Ba、Rb、Th和U等大离子亲石元素,亏损Nb、Ta和Ti等高场强元素,球粒陨石标准化稀土元素配分模式为右倾型,重稀土元素配分模式相对平坦,具有弱的Eu负异常,属I型花岗岩。岩体母岩浆来源于拆沉作用形成的镁铁质岩浆底侵地壳后部分熔融的产物,形成于后碰撞构造环境。The Riabayalou granite porphyry is located in the Chaxiaoma area,the northern margin of northern Qiangtang.The geochronology and whole-rock geochemistry of the granite porphyry show that the zircon U-Pb age is(64.46±0.60)Ma,indicating that the rock mass were formed in the early Paleocene.The granite porphyry is high in silicon,rich in alkali(K_(2)O+Na_(2)O=6.60%-8.81%),poor in MgO,TFe_(2)O_(3) and CaO,and belongs to the calc-alkaline aluminum-weak peralumin series.The rocks are rich in large ion lithophile elements and active incompatible elements such as Ba,Rb,Th and U,and depleted in high field strength elements such as Nb,Ta and Ti.The chondrite standardized rare earth element partition pattern is right-leaning type,and the HERR partition pattern is relatively flat with weak Eu negative anomaly,belonging to type I granite.The parent magma of the granite porphyry from the partial melting that penetrated the crust and formed in the post-collision tectonic environment.

关 键 词：北羌塘 日阿巴亚楼 花岗斑岩 锆石U-PB定年 地球化学特征 

分 类 号：P581[天文地球—岩石学]