投稿时间：2011-06-15
修订日期：2012-02-21
中文摘要:铜厂沟钼多金属矿床位于扬子陆块西缘坳陷带与义敦岛弧和甘孜-理塘结合带3个构造单元交汇部位,它是近年来对该区燕山期成矿作用研究并取得找矿突破的重要成果。该矿床包含了岩枝全岩矿化、顶部矽卡岩型及围岩热液脉型等热液交代矿化,构成了斑岩成矿系列。矿床已达大型,并显示出超大型的远景。运用辉钼矿Re-Os同位素定年技术,获得了6件样品的模式年龄,为(82.34±1.28)~(88.27±1.23) Ma,其加权平均年龄为(85±2) Ma,等时线年龄为(85±10) Ma,两者在误差范围内一致,表明成矿作用发生于燕山期,此时,该区处于中咱地块与扬子陆块强烈碰撞至后碰撞阶段,由于地壳加厚,壳熔或壳幔混熔形成了S型花岗(斑)岩和强烈的钼多金属矿化。铜厂沟矿床内辉钼矿样品的w(Re)为16 440~43 530 ng/g,指示其成矿物质来源为壳幔混源,以壳源物质为主。据野外调查和室内研究推测,在该矿区的深部存在燕山期的隐伏花岗(斑)岩体,成矿作用与岩浆上侵有关。该区的燕山期酸性岩带穿过了义敦岛弧进入扬子陆块西缘,呈近NS向展布,滇西北地区,北部从休瓦促向南至热林、红山、铜厂沟,形成了一系列大-中型钼多金属矿床。成矿背景和成矿预测研究对该带的找矿勘查具有十分重要的指导意义。
Abstract:The Tongchanggou Mo-polymetallic deposit lies in the western margin depression belt of the Yangtze landmass and is adjacent to Yidun island arc and Garze-Litang suture zone. It is a representative ore deposit in studying Yanshanian mineralization and shows bright future for further prospecting. Some intrusions (or apophyses) have been wholly mineralized, and hydrothermal metasomatism in the upper part mainly displays skarn type and hydrothermal vein type mineralization in wall rocks, forming a porphyry minerogenetic series. The ore deposit is a large-size or even a superlarge deposit. Re-Os isotopic dating technique was applied, and six molybdenite samples were analyzed for Re-Os isotopic compositions, and the model ages obtained are from (82.34±1.28) to (88.27±1.23) Ma, with the isochron age being (85±10) Ma. The result suggests that Mo mineralization occurred in Yanshanian period, during which Zhongza block and Yangtze landmass collided intensively and gradually turned into post-collision stage. Because of the thickening of the crust, crustal melting or crustal-mantle melting resulted in the formation of S-type granite and granite porphyry, accompanied by molybdenum polymetallic mineralization. The Re content of the molybdenite is 6 440~43 530 ng/g, suggesting that the metallogenic material originated from a source mixed with crust and mantle components. Field investigation shows that concealed granite intrusions may exist in the depth, and mineralization was related to magmatic intrusion. Acid intrusions in the area extend from north to south and the belt passes through Yidun arc and enters the western margin of Yangtze landmass. In northwestern Yunnan, a number of large-middle molybdenum polymetallic deposits were formed in the belt accordingly; they are scattered from north to south, represented by Xiuwacu, Relin, Hongshan and Tongchanggou. The research on metallogenic background and ore prognosis is of great signi-ficance for ore exploration in this area.
keywords:geochemistry Re-Os isotopic dating metallogenic age metallogenic environment Tongchanggou northwest Yunnan
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中图分类号：P618.65
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基金项目:本文得到国家重点基础研究发展计划(973计划)项目(编号: 2009CB421007)、国家科技支撑计划项目(编号:2006BAB01A07)和中国地质调查局地质调查工作项目(编号: 资[2010]矿评01-06-26)的联合资助
引用文本：
李文昌,余海军,尹光侯,曹晓民,黄定柱,董涛.2012.滇西北铜厂沟钼多金属矿床辉钼矿Re-Os 同位素年龄及其成矿环境[J].矿床地质,31(2):282~292LI WenChang,YU HaiJun,YIN GuangHou,CAO XiaoMin,HUANG DingZhu,DONG Tao.2012.Re-Os dating of molybdenite from Tongchanggou Mo-polymetallic deposit in northwest Yunnan and its metallogenic environment[J].Mineral Deposits31(2):282~292
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