| 铜陵矿集区铜金矿床叠加改造过程中的排金效应 |
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| 引用本文：.2004.Gold-Repelling Effect in Copper-Gold Deposits of Tongling Mineralization Cluster Area (MCA) in Process of Superimposition_Reformation [J].Mineral Deposits,23(2):216~224 |
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| 基金项目:国土资源部科技司专项研究计划(编号：B0002_2、B0002_3)和地质调查项目(编号：2001000 0004) |
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| 中文摘要:通过对铜陵地区各矿田内的矿床的观察发现，它们均含铜、金，但各 矿床含铜、金的差异性比较大。该区海西期同生沉积的SEDEX型块状硫化物矿床和燕山期岩 浆热液矿床的成矿物质来源具有二元性。在峙门口(铜金)硫铁矿、水竹岭金铜矿和虎山金矿 (牛山硫铁矿)等较为典型的海西期块状硫化物矿床中，可圈出独立的金(铜)矿体；以凤凰山 铜矿田、小金山金矿、笠帽山金矿等为典型代表的燕山期岩浆热液矿床，也具有较高的金、 铜品位，可形成工业矿体。但无论是海西期同生沉积矿床还是燕山期岩浆热液矿床，规模都 比较小。有些矿床尽管存在海西期同生沉积成矿作用和燕山期岩浆热液成矿作用，但铜、金 分配明显不同，品位差异悬殊。导致水平方向或垂直方向上铜、金分配差异的原因可归结为 矿床叠加改造过程中的温度场控制的“排金效应”，形成“下铜上金”、“内铜外金”(储 国正等，1992)的矿床分布格局。 |
| 中文关键词:地质学 排金效应 岩浆成矿 块状硫化物矿床 叠加改造 铜陵 |
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| Gold-Repelling Effect in Copper-Gold Deposits of Tongling Mineralization Cluster Area (MCA) in Process of Superimposition_Reformation |
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| Abstract:Based on observation of various deposits in Tongling area, Anhui Province, it is discovered that every deposit in the orefields contains more or less copper and gold, but with different concentrations. There exist two types of copper_ and g old_bearing deposits in Tongling area, i.e., Hercynian synsedimentary Sedex_type massive sulfide deposits and Yanshanian magmatic deposits. The Hercynian deposi ts are represented by the Zhimenkou Cu_Au_S_Fe deposit, the Shuizhuling Au_Cu de posit and the Hushan (or Niushan) Au (_S) deposit, which contain independent Au (_Cu) orebodies and thus serve as main mining objects. The typical Yanshanian ma gmatic deposits include the Fenghuangshan Cu orefield, the Xiaojinshan Au deposi t and the Limaoshan Au deposit, which have high grade of gold and can form econo mic orebodies. However, being relatively small in size, neither Hercynian synsed imentary deposits nor Yanshanian magmatic deposits can mention in the same breat h with such superimpositon deposits as the deposits in the Shizishan orefield an d the Tongguanshan orefield. It should also be noted that the deposits in Tongli ng area show prominent differences in the distribution of Cu, Au and Au, though these deposits occur in similar geological environments and are accompanied by H ercynian synsedimentary deposits and Yanshanian magmatic deposits. A comparison of the Dongguashan deposit with the Mashan deposit shows that, although they occ ur within the same horizon (Upper Carboniferous Huanglong Formation), the Donggu ashan deposit has only 0.15 g/t associated gold, while the Mashan deposit contai ns up to 10 g/t gold accompanied by 0.1% copper. Vertically, the Chaoshan gold m ine in the same orefield as the Dongguashan copper deposit contains up to 16.47 g/t gold associated with small amounts of lead and copper. The remarkable differ ences in the distribution of copper and gold in the deposits may be attributed t o the "gold_repelling effect" controlled by the temperature field in the superim position_reformation process of the deposits. Under the heating process, active gold migrates upward to accumulate at lower temperature whereas relative inert c opper is mostly immovable, thus resulting in a spatial distribution of deposits characterized by “copper at the lower part and gold at the upper part" and“cop per in the inner part and gold in the outer part”. |
| keywords:geology, gold_repelling effect, magmatic deposit, massive s ulfide deposit, superimposition_reformation, Tongling |
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