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现代地质 ›› 2015, Vol. 29 ›› Issue (4): 855-865.

• 岩石学与矿床学 • 上一篇    下一篇

黑龙江松嫩地块北缘晚三叠世—早侏罗世火山岩的发现及地质意义

吕长禄1,2,肖庆辉3,冯俊岭4 ,李新鹏2,邓昌州2,任凤和2,郑卫政2   

  1. (1.中国地质大学(北京) 地球科学与资源学院,北京100083; 2.黑龙江省地质调查研究总院,黑龙江 哈尔滨150036;
    3.中国地质调查局 发展研究中心,北京100037; 4.国土资源实物地质资料中心, 河北 三河065201)
  • 出版日期:2015-07-08 发布日期:2015-10-29
  • 作者简介:吕长禄,男,博士研究生,1968年出生,矿物学、岩石学、矿床学专业,从事区域地质及矿产研究等工作。Email:LCL51111@163.com。
  • 基金资助:

    中国地质调查局地质调查项目(1212011120682)。

The Discovery of Late Triassic-Early Jurassic Volcanic Rocks and Their  Geological Implications in Northern Songnen Block, Heilongjiang Province

Lv  Chang-lu1,2,XIAO Qing-hui3,FENG Jun-ling4,LI Xin-peng2,DENG Chang-zhou2,REN Feng-he2,ZHENG Wei-zheng2   

  1. (1.School of Earth Sciences and Resources,China University of Geosciences, Beijing100083, China;2.Geological Survey Institute of
    Heilongjiang, Harbin, Heilongjiang150036, China; 3.Development and Research Center, China Geological Survey,Beijing
    100037,China; 4.Material Geological Data Center of the Ministry of Land and Resources, Sanhe, Hebei065201, China)
  • Online:2015-07-08 Published:2015-10-29

摘要:

黑龙江省松嫩地块北缘大面积分布的玄武安山岩的时代厘定对讨论区域构造演化具有重要意义。对该区原划为早白垩世板子房组的玄武安山岩进行了LA-ICP-MS 锆石U-Pb年代学、岩石学和地球化学等研究,获得两个样品的锆石U-Pb年龄分别为(200.0±1.4)Ma和(200.0±1.3)Ma,表明其形成时代为晚三叠世—早侏罗世,并非早白垩世。岩石地球化学研究表明,玄武安山岩属准铝质,以高钾钙碱性系列为主,富集Ba、Rb、K、Pb等大离子亲石元素和轻稀土元素,亏损Nb、Ce、Nd、Ti等高场强元素和重稀土元素,为典型的大陆弧火山岩,表明松嫩地块小兴安岭—张广才岭存在一条近南北向展布的晚三叠世—早侏罗世火山岩带,该火山岩带与同时代略晚的花岗岩一起构成近南北向带状展布的中生代岩浆岩带。

关键词: 松嫩地块, 玄武安山岩, 锆石U-Pb年龄, 大陆弧火山岩

Abstract:

Basaltic andesites are widely distributed in the northern Songnen Block, Heilongjiang Province and their ages are critical to understand the regional tectonic evolution in this area. This study presents LA-ICP-MS zircon U-Pb age data and geochemical data for the basaltic andesite from the Banzifang Formation previously considered to be Early Cretaceous. Two samples yield U-Pb ages of (200.0±1.4)Ma and (200.0±1.3) Ma respectively,demonstrating that they were formed in Late TriassicEarly Jurassic rather than Early Cretaceous. The basaltic andesites are metaluminous, mainly high-K calc-alkaline. They are characterized by enrichment of large ion lithophile elements (LILE) such as Ba, Rb, K, Pb and LREE, depletion of high field strength elements (HFSE) such as Nb, Ce, Nd, Ti and HREE, indicating that the basaltic andesites belong to continental arc volcanic rocks. The results demonstrate that there has been Late Triassic-Early Jurassic volcanic belts in Xiaoxinganling-Zhangguangcailing, these occurrence, together with synchronous granites, comprise a Mesozoic N-S-striking magmatic belt.

Key words: Songnen block, basalt andesite, zircon U-Pb age, continental arc volcanic rock

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