摘要
通过对大兴安岭北段主脊呼源地区满克头鄂博组火山岩进行地质调查,采用锆石LA-ICP-MS UPb年代学和岩石地球化学研究,判断其形成时代并揭示其大地构造背景。满克头鄂博组下部岩石类型主要为英安质角砾凝灰岩、英安质凝灰岩,上部为英安岩、流纹岩等。锆石定年结果表明,满克头鄂博组形成年龄为150~159 Ma,时代属晚侏罗世。岩石地球化学分析结果显示,SiO_(2)含量在69.59%~80.54%,Al_(2)O_(3)为10.32%~14.93%,全碱(Na_(2)O+K_(2)O)为7.29%~9.89%,岩石属于高钾钙碱性系列;A/CNK为1.02~1.53,A/NK为1.05~1.56,属过铝质岩石,表现出壳源的特点。岩石稀土总量ΣREE=127.22×10^(-6)~191.26×10^(-6),轻重稀土分馏明显((La/Yb)_(N)=11.57~16.53),δEu为0.27~0.50;微量元素亏损Nb、Ta、Sr等,富集Rb、U、Th大离子亲石元素等,表明满克头鄂博组火山岩原始岩浆是地壳岩石的部分熔融产物,可能形成于蒙古-鄂霍茨克洋碰撞闭合后的岩石圈伸展塌陷构造环境。
Based on geological survey of volcanic rock in Manketouebo Formation of Huyuan area,the main ridge of the northern part of the Great Xing'an Mountains,zircon LA-ICP-MS U-Pb geochronology and petrogeochemical studies were used to determine the age of its formation and reveal its geological structure background.The lower part of Manketouebo Formation is mainly composed of dacite breccia tuff and dacite tuff,and the upper part is of dacite and rhyolite.The zircon dating results show that the age of the Manketouebo Forma-tion is 150-159 Ma,and belongs to the Late Jurassic.The rock geochemistry results show that the mass fraction of SiO_(2) is 69.59%-80.54%,the mass fraction of Al_(2)O_(3) is 10.32%-14.93%,the total alkali Na_(2)O+K_(2)O is 7.29%-9.89%,and the rock belongs to the high potassium calcium-alkaline series.A/CNK is 1.02-1.53,and A/NK is 1.05~1.56.It belongs to peraluminous rock and shows the characteristics of crust source.The total amounts of rare earth in the rocks are 127.22×10^(-6)-191.26×10^(-6).The light and heavy rare earth fractionation is obvious((La/Yb)_(N)=11.57-16.53).δEu=0.27-0.50.The trace elements are depleted of Nb,Ta,Sr,etc..The enrichment of Rb,U,Th large ion lithophile elements,etc.indicates that the original magma of the Manketouebo Formation volcanic rock is a partial melting product of crustal rocks,which may be formed in the lithospheric extension and collapse tectonic environment after the Mongolia-Okhotsk collision closed.
作者
赵强
汤静如
周青
舒广龙
马鹏
姜迎久
孙振江
ZHAO Qiang;TANG Jing-ru;ZHOU Qing;SHU Guang-long;MA Peng;JIANG Ying-jiu;SUN Zhen-jiang(College of Earth Sciences,Guilin University of Technology,Guilin 541006,China;Shenyang Institute of Geology and Mineral Resources,China Geological Survey,Shenyang 110034,China;No.9 Geological Exploration Institute of Heilongjiang Province,Qiqihar 161000,China)
出处
《桂林理工大学学报》
CAS
北大核心
2021年第3期497-509,共13页
Journal of Guilin University of Technology
基金
黑龙江省财政拨款项目(HLJKD2014-18)
广西自然科学基金项目(2018GXNSFAA281260)。
关键词
火山岩
地球化学
满克头鄂博组
大兴安岭北段
volcanic rock
geochemistry
Manketouebo Formation
northern Great Xing'an Range
