文章摘要
李玉龙,魏有宁,徐博,安朝,马正婷,王永文.东昆仑灶火河地区晚奥陶世侵入岩地球化学特征、锆石U-Pb年龄及其伸展构造环境的确定[J].矿产勘查,2020,11(8):1583-1591
东昆仑灶火河地区晚奥陶世侵入岩地球化学特征、锆石U-Pb年龄及其伸展构造环境的确定
Geochemistry ziron U-Pb ages of Late Ordovician intrusive rocks in the Zaohuohe area, East Kunlun and determination of its extensional structural environment
投稿时间:2019-09-26  
DOI:
中文关键词: 锆石U-Pb年龄  地球化学  斑状花岗闪长岩  晚奥陶世  灶火河地区  东昆仑
英文关键词: zircon U-Pb ages, geochemistry, porphyric granodiorite, Late Ordovician, Zaohuohe area, East Kunlun
基金项目:青海省地质勘查基金项目(编号:[2016]20)资助。
作者单位
李玉龙 青海省地质调查局,青海 西宁 810001 
魏有宁 青海省地质调查局,青海 西宁 810001 
徐博 青海省地质调查局,青海 西宁 810001 
安朝 青海省地质调查局,青海 西宁 810001 
马正婷 青海省地质调查局,青海 西宁 810001 
王永文 青海省地质调查院,青海 西宁 810012 
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中文摘要:
      灶火河地区位于东昆仑伯喀里克—香日德成矿带,为确定该区花岗闪长岩的形成时代、源区性质和构造背景,对其进行了LA-ICP-MS锆石U-Pb年代学和同位素及地球化学研究。结果显示岩体侵位时间为(449.9±1.4)Ma,属于晚奥陶世。岩石SiO2含量为71.99%~63.67%,Na2O含量为2.61%~3.43%、K2O含量为3.56%~5.81%,Al2O3含量为13.31%~15.28%,铝饱和指数A/CNK= 0.94~1.04,介于偏铝质和过铝质之间。稀土元素分布模式为轻稀土富集,具弱负Eu异常。相对原始地幔明显富集Zr、Ga、Y和Hf等高场强元素并强烈亏损Ba、Sr、P和Ti等特征,Zr含量远高于该带内分异或者未分异的I型花岗岩,以上特征表明灶火河地区晚奥陶世侵入岩属A型花岗岩,结合岩石成岩年龄、地球化学特征以及区域构造演化,认为其为陆-陆碰撞或岛弧岩浆作用之后伸展构造环境下的花岗岩。
英文摘要:
      The Zaohuohe area is located in the Bokalike-Xiangride metallogenic belt of the East Kunlun Mountains. To determine the formation age, source area and tectonic setting of the granodiorite in the area, LA-ICP-MS zircon U-Pb chronology and isotope and geochemistry research. The results show that the emplacement time of the rock mass is (449.9±1.4)Ma, belonging to the Late Ordovician. The content of SiO2 in rock is 71.99%-63.67%, the content of Na2O is 2.61%-3.43%, the content of K2O is 3.56%-5.81%, the content of Al2O3 is 13.31%-15.28% aluminum saturation index A/CNK=0.94-1.04, Between partial aluminum and over-aluminum. The distribution pattern of rare earth elements is light rare earth enrichment with weak negative Eu anomalies. Compared with the original mantle, the high field strength elements such as Zr, Ga, Y and Hf are obviously enriched and the characteristics such as Ba, Sr, P and Ti are strongly depleted. The Zr content is much higher than the I-type granite with in-band differentiation or undifferentiation. The above characteristics indicate that the Late Ordovician intrusive rocks in the Zaohuohe area belong to the A-type granite. Combined with the diagenetic age, geochemical characteristics and regional tectonic evolution of the rock, the tectonic setting is the granite under the extensional tectonic setting after the land-continent collision or island arc magmatism.
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