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铜陵铜官山矿田的中酸性侵入岩属高钾钙碱性系列,主要岩石类型为石英二长闪长岩和花岗闪长岩。本文对该矿田内的铜官山岩体和天鹅抱蛋岩体进行了锆石的SHRIMPU-Pb定年。结果表明,铜官山和天鹅抱蛋石英二长闪长岩的锆石SHRIMPU-Pb年龄几乎相同,分别为141.8±1.0Ma和141.3±1.3Ma,反映它们是同一次岩浆侵入作用的产物。结合锆石CL分析得出,两岩体中均含有新太古代、古元古代和新元古代岩浆型的继承性锆石核,说明本区岩浆的源岩含有古老的下地壳成分,锆石微量及稀土元素特征也表明其为陆壳而非洋壳成因,结合同位素和包体特征,得出岩浆来自富集地幔并含有古老地壳成分。
The medium-acid intrusive rocks in the Tongguanshan orefield in Tongling are high-K calc-alkaline series with the main types of rocks being quartz monzodiorite and granodiorite. In this paper, zircon SHRIMPU-Pb dating of Tongguanshan and Swanjiaojiao bodies in this field has been carried out. The results show that the zircon SHRIMPU-Pb ages of the Tongguanshan and swan asuite-monzodiorites are almost the same, which are 141.8 ± 1.0Ma and 141.3 ± 1.3Ma, respectively, indicating that they are the products of the same magmatic intrusion. Based on the analysis of zircon CL, it is concluded that the Neo-Archean, Paleoproterozoic and Neoproterozoic magmatic inherited zircon nuclei in both rocks show that the source rocks of the magma in this area contain the ancient lower crustal components and the zircons The characteristics of trace and rare earth elements also indicate that they are continental crust rather than oceanic crust. Combined with the characteristics of isotopes and inclusions, it is concluded that magma came from enrichment mantle and contains ancient crustal components.