汉南地区晋宁晚期铜-金成矿事件的确认及意义

发布时间：2018-09-08 20:40

【摘要】：汉南地区位于扬子克拉通北缘西段。目前,在川、陕两省已在该区发现了数十个矿床(点)。其中,广泛分布的铜-金矿床(点)具有热液型矿化特征,成矿条件有利,具有寻找大-中型矿床的远景。为了查明这些铜-金矿产资源的形成时代,文章运用LA-ICP-MS锆石U-Pb法和单矿物~(40)Ar/~(39)Ar法对汉南地区有代表性的矿床(点)进行了成矿年代学研究。其结果显示,潘坝成矿期热液脉的锆石U-Pb年龄为(744±10)Ma,黑云母和钾长石~(40)Ar/~(39)Ar视年龄介于740 Ma~700 Ma之间。元山寺的成矿期白云母~(40)Ar/~(39)Ar坪年龄为(744±4)Ma,等时线年龄为(748±7)Ma。由于本次测试选择了成矿期矿物,其结果可以代表成矿时代。因此,汉南很可能存在晋宁晚期的铜-金成矿事件。根据区域地质演化历史,笔者认为汉南铜-金矿化(744 Ma)是造山晚期加厚岩石圈下部(山根)拆沉的结果。
[Abstract]:Hannan area is located in the western section of the northern margin of Yangtze craton. At present, in Sichuan, Shaanxi and Shaanxi provinces have found dozens of deposits (points) in the area. Among them, the widely distributed copper-gold deposits have the characteristics of hydrothermal mineralization, favorable metallogenic conditions and the prospect of prospecting for large and medium-sized deposits. In order to find out the forming age of these copper-gold mineral resources, LA-ICP-MS zircon U-Pb method and single mineral ~ (40) Ar/~ (39) Ar method are used to study the metallogenic chronology of representative deposits (points) in Hannan area. The results show that the zircon U-Pb age of hydrothermal veins in Panba metallogenic period is (744 卤10) Ma, biotite and potassium feldspar ~ (40) Ar/~ (39) Ar. The ~ (40) Ar/~ (39) Ar plateau age of Muscovite in Yuanshansi metallogenic period is (744 卤4) Ma, isochron age of (748 卤7) Ma.. Because of the mineral selection in this test, the result can represent the metallogenic age. Therefore, it is very likely that the late Jinning copper-gold mineralization event occurred in Hannan. According to the history of regional geological evolution, the authors believe that the Cu-au mineralization (744 Ma) in Hannan is the result of the lower part (root) of the thickened lithosphere in the late orogenic period.
【作者单位】：中国地质科学院地质力学研究所;陕西省地质矿产勘查开发总公司第二分公司;陕西矿业开发工贸公司;陕西省矿产资源勘查与综合利用重点实验室;
【基金】：陕西省矿产资源勘查与综合利用重点实验室基金(编号:2014-01) 地质力学研究所基本科研业务费(编号:DZLXJK201302) 地质调查项目钦杭结合带及邻区深部地质调查项目(编号:121201104000160916) 国土资源部公益性行业科研专项经费资助(编号:201311036-02) 国家自然科学基金项目“川东北双弧构造形成机理"(编号41172184)联合资助
【分类号】：P618.41;P618.51

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