| 安徽铜陵冬瓜山铜矿床的叠加改造成矿机制：来自矿石结构的证据 |
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| 引用本文： | 郭维民,陆建军,章荣清,徐兆文.安徽铜陵冬瓜山铜矿床的叠加改造成矿机制：来自矿石结构的证据[J].地质学报,2011,85(7):1223-1232. |
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| 作者姓名： | 郭维民 陆建军 章荣清 徐兆文 |
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| 作者单位： | 南京大学成矿作用国家重点实验室,南京大学地球科学与工程学院,南京,210093 |
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| 摘 要： | 长江中、下游地区块状硫化物矿床普遍受到燕山期岩浆及其热液的改造与叠加.本文以铜陵冬瓜山矿床为例,探讨这类矿床的成矿机制.该矿床主要由层状硫化物矿体组成,伴有矽卡岩型和斑岩型矿体.野外地质观察及室内矿相学的研究表明,冬瓜山层状矿体中矿石遭受了强烈的热变质作用及热液交代作用.进变质过程中形成的结构主要为黄铁矿受燕山期岩浆侵...
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| 关 键 词： | 矿石结构 冬瓜山铜矿床 叠加改造 铜陵 |
| 收稿时间： | 2009/6/16 0:00:00 |
| 修稿时间： | 2010/2/25 0:00:00 |
The superimposed mineralization of the Dongguashan Cu deposit in Tongling Area, Anhui Province: evidence from the ore texture |
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| Guo weimin,LU jianjun,ZHANG rongqing and XU zhaowen.The superimposed mineralization of the Dongguashan Cu deposit in Tongling Area, Anhui Province: evidence from the ore texture[J].Acta Geologica Sinica,2011,85(7):1223-1232. |
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| Authors: | Guo weimin LU jianjun ZHANG rongqing and XU zhaowen |
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| Institution: | School of Earth Sciences and Engineering,School of Earth Sciences and Engineering,School of Earth Sciences and Engineering,School of Earth Sciences and Engineering |
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| Abstract: | The massive sulfide deposits in the middle-lower region of Yangtze River have undergone extensive superimposition and reformation by Yanshanian magma. Taking the Dongguashan Cu deposit in Tongling as a study case, this paper discusses the metallogenic mechanism of these Cu deposits. Dongguashan deposit comprises mainly of a large stratiform sulfide orebody with some subordinate skarn and porphyry type orebodies. Field and microscopic investigation show that the sulfide ores at Dongguashan deposit underwent intensive thermal metamorphism and hydrothermal replacement. The prograde ore textures were formed through the phase conversions from pyrite to pyrrhotite and magnetite by the heating of magma. Retrograde metamorphism is characterized by presence of annealing textures in pyrrhotite, porphyroblastic growth of pyrite and formation of pure hexagonal pyrrhotite. The hydrothermal replacement textures were represented by the intergrowths of hexagonal and monoclinic pyrrhotites and replacement of pyrrhotites and pyrite by chalcopyrite. The chalcopyrite in the stratiform sulfide orebody was mainly overprinted from the magmatic fluids by reaction with the pyrrhotite and pyrite. The pre-existing pyrrhotite and pyrite have important significance for the precipitation of chalcopyrite from magmatic fluids. Base on the characteristics of ore textures, the formation of Dongguashan Cu deposit can be described as three stages: 1) During the Carboniferous period, the massive sulfide deposit was formed by the submarine exhalative and sedimentation, the compositions of which were dominantly S and Fe; 2) Granite intrusions have intruded the environment of the sulphide deposits, the heat from the magmas has resulted in phase changes from the pyrite to pyrrhotites and magnetite, and underwent a slow cooling process; 3) The overprinting of magmatic hydrothermal fluids lead to enrichment of large amounts of copper in the stratiform orebody, and formed new skarn and porphyry type orebodies. |
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| Keywords: | Ore texture Dongguashan copper deposit superimposition-reformation pyrite Pyrrhotite |
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