中祁连东段白花沟岩体地球化学特征及年代学意义  

The geochemical characteristics and chronological significance of Baihuagou pluton at the eastern section of central Qilian

作　　者：高亮[1] 任二峰[1] 李杰[2] 康伟浩 

机构地区：[1]青海大学,青海西宁810016 [2]青海省地质调查院,青海西宁810012

出　　处：《青海大学学报（自然科学版）》2017年第4期1-7,共7页Journal of Qinghai University(Natural Science)

基　　金：青海省科学技术厅基金项目(2016-ZJ-752);中国地质调查局项目(1212011121196);地质资源与地质工程创新团队(4056051201)

摘　　要：为了研究中祁连东段白花沟岩体的地球化学特征,通过LA-ICP-MS方法测得花岗闪长岩同位素年龄为(922±16)Ma(MSWD=2.0),侵位时代为新元古代。岩石中SiO_2含量为64.4%~75%,Al_2O_3含量为12.98%~15.75%,MgO含量为0.34%~2.25%,Na_2O/K_2O>1,总体显示为过铝质花岗岩类;微量元素方面,Sr含量较低,属于低Sr花岗岩,Ba,Sr,Nb,Eu表示出明显的负异常;轻稀土表现出强烈富集的特征,δEu<1(0.36~0.82),具有明显的负异常。白花沟岩体形成于晋宁运动前期的一次碰撞造山运动,为古老陆壳的重融,其源岩为贫粘土、富斜长石的砂屑岩。Our purpose was to study the geochemical characteristics of Baihuagou pluton lying in the eastern central Qilian. The results of LA - ICP - MS isotope age show 922 ＋ 16 Ma （ MSWD =2. 0） , the age of Neoproterozoic. Compositionally, SiO 2 values range from 64. 4 % to 75 % ,Al2O3 from 12. 98% to 15. 75%, MgO from 0. 34 % to 2. 55 % , and Na2O/K〈 20 〉 1 , suggesting the pluton is peraluminous granitoids. In addition,the rocks have low Sr content,belonging to low Sr granite.Ba,Sr,Nb and Eu show obvious negative anomaly. The rocks are rich in LREE, with obvious neg-ative anomaly of 8Eu, 8Eu 〈1 （0. 36-0. 82） . Baihuagou pluton formed in a collision orogeny in the early stage of the Jinning movement, it comes from the remelting of ancient continental crust, and the source rock contains poor clay and mass of plagioclase.

关 键 词：过铝质花岗岩 锆石U-PB年龄 白花沟岩体 地球化学 中祁连 

分 类 号：P597[天文地球—地球化学]