文章摘要
杨雪松,王国良,余福承,孟红,赵景.青海窑洞山地区晚奥陶世花岗岩岩石地球化学特征及地质意义[J].矿产勘查,2019,(3):424-433
青海窑洞山地区晚奥陶世花岗岩岩石地球化学特征及地质意义
Geochemical characteristics and geological significance of Late Ordovician granite in Yadongshan Area of Qinghai Province
投稿时间:2018-10-18  
DOI:
中文关键词: 钙碱性系列  壳源花岗岩  碰撞花岗岩  岛弧  U-Pb年龄
英文关键词: calcium alkalescence siries, crusta source granite,collision granite, island arc, U-Pb age
基金项目:中国地质调查局大调查项目(编号:12120113033014)资助。
作者单位
杨雪松 青海省青藏高原北部地质过程与矿产资源重点实验室,西宁 810012
青海省地质调查院,西宁 810012 
王国良 青海省青藏高原北部地质过程与矿产资源重点实验室,西宁 810012
青海省地质调查院,西宁 810012 
余福承 青海省青藏高原北部地质过程与矿产资源重点实验室,西宁 810012
青海省地质调查院,西宁 810012 
孟红 青海省青藏高原北部地质过程与矿产资源重点实验室,西宁 810012
青海省地质调查院,西宁 810012 
赵景 青海省青藏高原北部地质过程与矿产资源重点实验室,西宁 810012
青海省地质调查院,西宁 810012 
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中文摘要:
      对青海省格尔木窑洞山地区四道沟侵入岩进行岩石学、岩石化学、微量元素的分析及研究,主要岩石类型有二长花岗岩、二云母二长花岗岩和白云母花岗岩等,SiO2含量为65.65%~77.32%,K2O、Na2O分别含量为2.78%~7.73%和1.26%~5.78%,显示钙碱性系列特征,σ=0.61~2.07, Al2O3>CaO+K2O+Na2O,A/CNK=1.09~2.48,为中高钾过铝质岩石。LREE/REE=3.30~6.24,δEu=0.37~0.56,均小于1,具明显的负铕异常。K、Rb、Ba、Th、Ce富集,其中Ba具负异常特征,Ta、Zr亏损,具碰撞花岗岩特征。由上述特征表明,窑洞山地区的晚奥陶世花岗岩具壳源花岗岩(S型)特征,是非典型碰撞型花岗岩,形成于岛弧或陆缘弧部位。同时在四道沟西侧的二云母二长花岗岩中获得(471±2)Ma LA-ICP-MS锆石U-Pb年龄,为东昆仑地区古生代多级构造—岩浆演化提供了精确的地质时代证据。
英文摘要:
      The analysis and study of petrology, petrochemistry and trace elements of the Sidao gou in Yaodongshan area of Golmud City, Qinghai Province, the main rock types are monzonite granites, Biotite-Mus monzonite granites and muscovite granites, the rocks have the following chemical composition:siO2 = 65.65 %~ 77.32 %, K2O and Na2O are different between 2.78% ~7.73 % and 1.26% ~5.78 %, This indicates the granite rocks with the character of calcium alkalescence siries. σ = 0.61 ~ 2.07, Al2O3 > CaO + K2O + Na2O, A/CNK = 1.09 ~ 2.48, They are medium-high potassium aluminum rocks. LREE/REE = 3.30 ~ 6.24, Δ Eu = 0.37 ~ 0.56, all less than 1, indicate Eu pronounced Obviously negative abnormalty. K, Rb, Ba, Th, Ce are abundant, of which Ba has negative abnormalty, Ta, Zr are loss-making, with collision granite characteristics. From the above characteristics, it is shown that the late Ordovician granites in the Yaodongshan area are Crustal granite(S-type granite), Atypical Syn-Collision granite,formed in island arcs or continental margin arcs. At the same time, We took a sample of the Biotite-Mus monzonite granites in the Yaodongshan area to analys U-Pb age.The LA-ICP-MS U-Pb age analyses show that the granite ages of late Ordovician are (471±2)Ma, the zircon trace elements age provide accurately Geological Age on the Paleozoic multi-stage tectonic-magmatic events of the Eastern Kunlun area.
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