J4 ›› 2011, Vol. 41 ›› Issue (6): 1689-1704.

• 兴蒙造山带及邻区中生代岩浆活动与金属成矿作用专辑 • 上一篇    下一篇

巴尔哲地区碱性花岗岩的成岩和成矿作用:矿化和未矿化岩体的比较

杨武斌1,2, 单强1, 赵振华1, 罗勇3, 于学元1, 李宁波1,2, 牛贺才1   

  1. 1.中国科学院广州地球化学研究所/矿物学与成矿学重点实验室|广州510640;
    2.中国科学院研究生院|北京100049;
    3.南阳师范学院环境科学与旅游学院| 河南 南阳473061
  • 收稿日期:2011-07-26 出版日期:2011-11-26 发布日期:2011-11-26
  • 通讯作者: 牛贺才(1963-),男,河北容城人,研究员,主要从事地球化学方面研究 E-mail:niuhc@gig.ac.cn
  • 作者简介:杨武斌(1984-)|男|江西樟树人|博士研究生|主要从事地球化学方面研究|E-mail:yangwubin@gig.ac.cn
  • 基金资助:

    国家自然科学基金项目(40872066);国家重点自然科学基金项目(41030421)

Petrogenic and Metallogenic Action of the Alkaline Granitoids in Baerzhe Area: A Comparison Between Mineralized and Barren Plutons

YANG Wu-bin1,2,SHAN Qiang1,ZHAO Zhen-hua1,LUO Yong3,YU Xue-yuan1,LI Ning-bo1,2, NIU He-cai1   

  1. 1. Guangzhou Institute of Geochemistry/Key Laboratory of Mineralogy and Metallogeny,CAS, Guangzhou510640, China;
    2.Graduate University of Chinese Academy of Science, Beijing100049, China;
    3.School of Environmental Science and Tourism, Nanyang Normal University, Nanyang473061, Henan, China
  • Received:2011-07-26 Online:2011-11-26 Published:2011-11-26

摘要:

巴尔哲地区碱性花岗岩由801和802两个岩体组成:801岩体为典型的稀有稀土矿化碱性花岗岩,其中锆和稀土元素的储量已达超大型矿床规模;802岩体稀土元素和某些稀有元素含量也较高,但未形成工业矿床。对巴尔哲地区碱性花岗岩进行了主量元素、微量元素和Sr-Nd同位素地球化学研究,研究结果表明:矿化和未矿化碱性花岗岩体为同源岩浆,具有富集地幔源的特征,在其侵位过程中没有受到同化混染作用的影响。主量元素和微量元素地球化学特征显示,在脱离源区时802岩体的原始岩浆演化程度明显高于801岩体的原始岩浆,因此802岩体的成矿潜力应大于801岩体。801岩体具有明显的岩相分带,可以分上下2个岩相带:上部为钠长石花岗岩带,下部为钠闪石花岗岩带。在上部岩相带中分布着相当数量的伟晶岩块(壳)和晶洞,在该岩相带的石英(斑晶和伟晶岩)中存在着大量的流体-熔体包裹体以及岩石具有明显的稀土四分组效应,这些地质地球化学特征均暗示801岩体的原始岩浆在侵位后发生充分的分异演化;802岩体具有典型的浅成-超浅成侵入相岩石的结构特征,且该岩体岩石的主量元素和微量元素组成相对均匀,表明802岩体的原始岩浆在侵位后没有经历明显的分异演化过程。显然,岩浆侵位后分异演化程度对巴尔哲地区碱性花岗岩的稀有稀土元素成矿作用具有明显的制约。

关键词: 巴尔哲, 碱性花岗岩, 岩浆-热液演化, 超大型稀土-铌-铍-锆矿床, 矿化和未矿化

Abstract:

Baerzhe alkaline granite is composed of No. 801 and No. 802 plutons, in which the 801 pluton is a superlarge rare earth and REE mineralized alkaline granitic intrusion and the 802 pluton is a non-mineralized pluton in which REE and some rare-elements are also slightly concentrated. A comparative study of major and trace elements and isotopic geochemistry of the mineralized 801 alkaline granite and the associated barren 802 alkaline granite in Baerzhe area was carried out, and the results show that both the mineralized and barren alkaline granites are characterized by enrichment of mantle isotopes, with no significant effect of assimilation. Geochemistry of major and trace elements suggests that the primary magma of the 802 pluton experienced a higher degree of evolution than the 801 pluton, which means that the 802 pluton has further potential for rare metal exploration. Petrographic zonation, pegmatite, miarolitic cavities and fluid-melt inclusions are well developed in the 801 pluton, suggesting that a full differentiation and evolution occurred after the intrusion of the primary magma. On the contrary, the 802 pluton is characterized by a porphyry texture of shallow intrusive rock and a relatively uniform major and trace element abundance, implying rapid cooling and non-differentiation after the emplacement of the primary magma of the 802 pluton. It is obvious that high differentiation and evolution that occurred in a relatively isolated system after the intrusion of the alkaline magma was the dominant factor for the rare-earth and REE mineralization of Baerzhe alkaline granites.

Key words: Baerzhe, alkaline granite, magmatic-hydrothermal evolution, superlarge REE-Nb-Be-Zr deposit, mineralized and barren

中图分类号: 

  • P618.7
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