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内蒙古东乌旗索纳嘠铅锌银矿区赋矿侵入岩为一由中粗粒花岗岩、细粒黑云母花岗岩和似斑状钾长花岗岩组成的杂岩体。三种岩石的锆石U-Pb同位素年龄依次为(319.6±4.1)Ma、(172.5±1.4)Ma和(165.5±1.8)Ma。三者均以高钾、富碱、贫镁为特征,均属钙碱性、准铝质—弱过铝质岩石,分异程度较高。岩石稀土总量较高,轻稀土相对富集,均具负铕异常;均富集U、Th,Rb/Sr值大于壳源Rb/Sr值,应属S型花岗岩。根据花岗岩地球化学和区域地质特征分析认为,中粗粒花岗岩形成于晚石炭世后碰撞伸展构造环境;中侏罗世细粒黑云母花岗岩和似斑状钾长花岗岩产于板内伸展构造环境,为同源岩浆演化不同阶段的产物。似斑状钾长花岗岩富含成矿元素Pb和Zn,而且其成岩年龄与辉钼矿(163.4±2.4)Ma～(166.6±2.4)Ma的Re-Os同位素年龄基本一致,可能为成矿母岩。
The ore-bearing intrusive rocks in the Sonarite lead-zinc-silver deposit in Dongwuqi, Inner Mongolia, are complex complexes of medium- and coarse-grained granites, fine-grained biotite granites and plagioclase-like potassium long granites. The U-Pb zircon ages of the three rocks are (319.6 ± 4.1) Ma, (172.5 ± 1.4) Ma and (165.5 ± 1.8) Ma, respectively. All of them are characterized by high potassium, alkali-rich and poor magnesium, all of which are calc-alkaline, quasi-aluminum-weak perlite, with higher degree of differentiation. The total amount of rare earth rocks is relatively high, while the light rare earths are relatively enriched, all of them have negative Eu anomalies. The average enrichment of U, Th and Rb / Sr values is larger than the Rb / Sr value of shell source, and should be S-type granite. According to the analysis of granitogeochemistry and regional geological features, it is considered that the coarse-grained granites were formed in the post-Carboniferous post-collision extensional tectonic setting. Middle-Jurassic fine-grained biotite granites and macular platy-shaped potassium granites were produced in extensional tectonic setting within the plate, The product of different stages of magmatic evolution. The plagioclase-like granite is rich in metallogenic elements Pb and Zn, and its diagenetic age is basically consistent with the Re-Os isotopic ages of molybdenite (163.4 ± 2.4) Ma ~ (166.6 ± 2.4) Ma, which may be metallogenic host rocks .