摘要
普朗斑岩铜矿在中国斑岩铜矿床中有其特殊性,无论对中甸岛弧带的基础地质还是矿产资源评价预测的研究,都具有重要意义。然而,该斑岩铜矿床无确切的年代学数据。通过作辉钼矿Re-Os年龄和单矿物K-Ar年龄测定,首次确定了普朗斑岩铜矿床内具有钾硅酸盐化的黑云石英二长斑岩成矿作用的活动时间为(235.4±2.4)Ma～(221.5±2.0)Ma,石英-辉钼矿阶段的辉钼矿Re-Os年龄大致为(213±3.8)Ma,两者十分相近。表明普朗斑岩铜矿床的成矿作用是在印支期完成的。主矿体钾长石K-Ar年龄显示热液活动持续到(182.5±1.8)Ma左右,说明与斑岩铜矿有关的热液系统寿命可达40Ma之久。这种长寿命的热液系统是高品位大规模的斑岩铜矿形成的必要条件之一。
The Pulang porphyry copper has its peculiarity in China's porphyry deposits. It is of great significance for both basic geological research and evaluation of mineral resources in the Zhongdian island-arc zone. However, no precise chronological data are available about the porphyry copper deposit. By molybdenite Re-Os dating and single-grain K-Ar dating, it was for the first time determined that the age of mineralization of biotite-quartz monzonite-porphyry in the Pulang porphyry copper ranges from 235.4±2.4 to 221.5±2.0 Ma, while the molybdenite Re-Os age of the quartz-molybdenite stage is ～213±3.8 Ma. The two ages are close to each other, which suggests that mineralization of the Pulang porphyry copper deposit occurred in the Indosinian. The K-feldspar K-Ar dating of the main orebodies reveals that the hydrothermal activity related to porphyry copper continued to ～182.5±1.8 Ma, suggesting that the lifespan of the hydrothermal system lasted at least 40 Ma. This long-active hydrothermal system may be one of the necessary conditions for producing large high-grade porphyry copper deposits.
出处
《地质通报》
CAS
CSCD
北大核心
2004年第11期1127-1131,共5页
Geological Bulletin of China
基金
国土资源调查项目(编号:200310200001-4)
国家自然科学基金项目(编号:40272046)
973项目(编号:2002CB412610)资助。
