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    陈丽丽, 程志国. 内蒙古兴安盟杜尔基地区花岗岩矿物学特征和Hf同位素研究[J]. 中国地质, 2016, 43(4): 1189-1199. DOI: 10.12029/gc20160406
    引用本文: 陈丽丽, 程志国. 内蒙古兴安盟杜尔基地区花岗岩矿物学特征和Hf同位素研究[J]. 中国地质, 2016, 43(4): 1189-1199. DOI: 10.12029/gc20160406
    CHEN Li-li, CHENG Zhi-guo. Mineralogical and Hf isotope study of the Dorolj granite in Hinggan League, Inner Mongolia[J]. GEOLOGY IN CHINA, 2016, 43(4): 1189-1199. DOI: 10.12029/gc20160406
    Citation: CHEN Li-li, CHENG Zhi-guo. Mineralogical and Hf isotope study of the Dorolj granite in Hinggan League, Inner Mongolia[J]. GEOLOGY IN CHINA, 2016, 43(4): 1189-1199. DOI: 10.12029/gc20160406

    内蒙古兴安盟杜尔基地区花岗岩矿物学特征和Hf同位素研究

    Mineralogical and Hf isotope study of the Dorolj granite in Hinggan League, Inner Mongolia

    • 摘要: 杜尔基花岗岩基位于大兴安岭中南段,且处在大兴安岭一个大型多金属矿集区(Au-Ag-Cu-Zn-Sn-Fe)中。区内岩浆活动复杂,成矿元素多样,其中,杜尔基花岗岩是本地区出露面积较大(约190 km2)的岩体之一。为厘清区内不同花岗质岩石的源区特征及其与成矿的关系,文章对杜尔基地区花岗岩的主要岩性单元二长花岗岩和正长花岗岩进行了系统的矿物学和Hf同位素组成研究。结果表明:二长花岗岩的主要矿物为斜长石(32%)、钾长石(45%)、石英(20%),次要矿物为黑云母、角闪石和辉石等暗色矿物(3%);正长花岗岩的主要组成矿物为石英(10%~15%)、钾长石(60%~70%)和斜长石(30%),次要矿物为黑云母(5%),在这两种花岗岩中均广泛发育条纹长石。黑云母主要为铁质黑云母和铁叶云母,角闪石为韭闪石和普通角闪石,辉石为普通辉石。矿物学特征均指示杜尔基花岗岩主要为I型花岗岩。二长花岗岩εHf为-1.6~17.6,正长花岗岩εHf为-3.3~12.2。杜尔基花岗岩Hf同位素特征指示其源区为新生的地壳物质,可能是来自地幔的底侵玄武质岩浆发生重熔的结果。

       

      Abstract: The Doroji granite is located in the southern part of the Da Hinggan Mountains, lying in a polymetallic ore-forming zone (Au-Ag-Cu-Zn-Sn-Fe) of the Da Hinggan Mountains. There are various kinds of magmatic rocks in this area, with multiple metallogenic elements, and Doroji granite is one of the biggest plutons, with an exposed area of about 190 km2. To clarify the source of the Doroji granite and the relationship with the mineralization, the authors conducted a systematic study of the mineralogy and Hfisotopic compositions. Doroji granite is dominated by monzonitic granite and syenogranite. The monzonitic granite is composed of plagioclase (32%), K-feldspar (45%), quartz (20%), with miner biotite, muscovite, amphibole and pyroxene (3%). The syenogranite consists of quartz (10%-15%), K-feldspar (60%-70%), plagioclase (30%) with minor biotite (about 5%). Perthites is well developed in the monzonitic granite and syenogranite. Biotites are mainly ferribiotite and siderophyllite. Amphiboles are mainly kaersutite and hornblende. Pyroxenes are augites. The mineralogy indicates that the Doroji granite belongs to I-type. The εHf values of monzonitic granite range from-1.6 to 17.6, and the εHf values of syenogranite range from-3.3 to 12.2. Hf isotopic compositions of the Doroji granite indicates that the source was the juvenile crust, resulting from the remelting of the depleted basaltic rocks.

       

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