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欧布拉格铜-金矿床位于内蒙古西部阿拉善地区,是一处远景具大型规模的铜-金矿床。矿床赋存于二叠系下统火山岩和次火山岩中,容矿岩石主要为石英斑岩和英安质熔结火山角砾岩、流纹质火山角砾岩。本文选取矿区出露的与矿化最为密切的样品,采用颗粒锆石U-Pb法和40Ar/39Ar法测定了成矿期石英斑岩脉和含矿石英脉的年龄,获得成矿期石英斑岩的锆石U-Pb年龄为277.4±3 Ma,铜-金矿体中石英的40Ar/39Ar年龄为264.26±0.46 Ma。这一结果揭示,欧布拉格铜-金矿是海西晚期形成的。结合阿拉善地区的朱拉扎嘎金矿和呼伦西白金矿都是海西晚期形成的情况分析,表明海西晚期是中国西部最重要的铜(金)矿化期之一。
The Oubrague copper-gold deposit, located in the Alashan region of western Inner Mongolia, is a large-scale copper-gold prospect. The ore deposits occur in the Lower Permian volcanic rocks and subvolcanic rocks. The ore-bearing rocks are mainly quartz porphyry and the British amphibolite-bearing volcanic breccia and rhyolitic volcanic breccia. In this paper, the most mineralized samples that are exposed in the mining area are selected. The ages of quartz porphyry veins and ore-bearing quartz veins in the ore-forming period are determined by U-Pb method and 40Ar / 39Ar method, The zircon U-Pb ages of rocks are 277.4 ± 3 Ma, and the 40Ar / 39Ar ages of quartz in copper-gold ore bodies are 264.26 ± 0.46 Ma. This result reveals that the Oubrav copper-gold mine was formed in the late Hercynian period. The combination of Zhulazaga gold mine and Hulunseibai gold mine in the Alashan region are both formed in the late Hercynian period, suggesting that the late Hercynian period was one of the most important copper (gold) mineralization stages in western China.