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现代地质 ›› 2016, Vol. 30 ›› Issue (3): 528-540.

• 岩石学与矿床学 • 上一篇    下一篇

内蒙古乌日尼图花岗岩的年代学、地球化学及其地质意义

杨增海1,2,王建平2,刘家军2,王守光3,王清义4,康书光4,张捷先2,赵云2   

  1. (1. 中国黄金集团公司,北京 100011;2. 中国地质大学(北京)地球科学与资源学院,北京 100083;3. 内蒙古自治区地质调查院,内蒙古 呼和浩特 010020;
    4. 内蒙古自治区第九地质矿产勘查开发院,内蒙古 锡林浩特 026000)
  • 出版日期:2016-06-14 发布日期:2016-06-15
  • 通讯作者: 王建平,男,副教授,1972年出生,矿物学、岩石学、矿床学专业,主要从事矿床学与矿床地球化学的研究。Email: jpwang@ cugb.edu.cn。
  • 作者简介:杨增海,男,工程师,1982年出生,矿物学、岩石学、矿床学专业,主要从事矿床学与矿床地球化学的研究。Email:yangzenghai21023@163.com。
  • 基金资助:

    中国地质调查局矿产资源调查评价专项“重要示范区带区域成矿系统研究”(1212011085471)。

Geochronology and Geochemistry of the Wurinitu Granites in Inner Mongolia and Their Geological Implications

YANH Zenghai1,2, WANG Jianping2, LIU Jiajun2, WANG Shouguang3, WANG Qingyi4, KANG Shuguang4, ZHANG Jiexian2, ZHAO Yun2   

  1. (1. China National Gold Group Corporation, Beijing 100011,China; 2. School of Earth Sciences and Resources, China University of Geosciences,  Beijing 100083, China; 3. Geological Survey Institute of Inner Mongolia,Huhehaote,Inner Mongolia010020,China;  4.  Inner Mongolia Ninth Geological Mineral Exploration Institute, Xilinhaote, Inner Mongolia 026000,China)
  • Online:2016-06-14 Published:2016-06-15

摘要:

乌日尼图隐伏岩体位于内蒙古自治区苏尼特左旗查干敖包镇西北乌日尼图地区,主要岩石类型为细粒—中细粒花岗岩、二长花岗岩。岩相学及地球化学特征研究表明,乌日尼图花岗岩体属于高钾钙碱性岩系,SiO2含量为74.85%~78.10%,K2O/Na2O比值介于1.45~3.08之间,铝指数A/CNK=1.00~1.21,属过铝质岩石。主微量稀土元素分析表明,该岩体富集Rb、Th、U等元素而Ba、Nb、Sr、P和Ti强烈亏损,Eu为负异常(δEu= 0.22~0.39),总体呈现轻稀土富集的右倾“V”形分布配分模式。LA-ICP-MS锆石U-Pb定年表明,乌日尼图花岗岩体形成于早白垩世(139 Ma),为燕山运动晚期的产物。乌日尼图花岗岩体属A型花岗岩,形成于伸展的大地构造环境,且源区成分不均一,源岩可能主要由富黏土的泥质岩夹杂少量砂屑岩变质形成。

关键词: 钨钼矿床, 花岗岩, 地质年代学, 地球化学, 乌日尼图, 内蒙古

Abstract:

The Wurinitu granitoid pluton, located in the northwestern of the Wurinitu Village, Chaganaobao town, Sunidzuoqi County, Inner Mongolia, is a concealed rock mass and mainly composed of fine to middle-fine grained granite and adamellite. Petrography and geochemical characteristics indicate that it belongs to high-K calc-alkaline series. Its SiO2 contents range from 74.85% to 78.10%, while K2O/Na2O ratios and A/CNK values vary from 1.45 to 3.08 and 1.00 to 1.21, supposed to a suite of peraluminous rock. Rb, Th and U elements are enriched in the intrusion while Ba, Nb, Sr, P and Ti depleted. REEs show characteristics of obvious negative Eu anomalies(δEu= 0.22-0.39)and right-dipping“V”patterns with LREE enrichment. On the basis of LA-ICP-MS U-Pb chronological study of zircons, the U-Pb dating results from the granites are 139 Ma implying that they formed in Early Cretaceous, Late Yanshanian stage. Chemically, the granitoids belong to A-type, implying that they formed under an extensional tectonic setting. The source compositions of the granites are different, and they are mainly derived from clay-rich pelite with a spot of arenite, resulted from metamorphism.

Key words: W-Mo deposit, granite, geochronology, geochemistry, Wurinitu, Inner Mongolia

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