| 江西银山矿床矿物共生组合的重新厘定及其成因意义 |
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| 引用本文：.1997.Reidentification of mineral associations in the Yinshan polymetallic deposit fo Jiangxi Province and their genetic implications[J].Mineral Deposits,16(4):309~317 |
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| 基金项目:国家自然科学基金（49272110）和中国科学院矿床地球化学开放研究实验室基金 |
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| 中文摘要:江西银山多金属矿床发育南北不对称的矿化与蚀变分带，并以矿区南部的分带性较完整。研究表明，其矿区南部矿化分带的形成，是在成矿热液的缓慢演化过程中各种成矿元素依次沉淀的结果，其中石英或菱铁矿的梳状构造发育，线型蚀变较强，所形成的矿物自形程度高，杂质组分含量低；矿区北部九区含铜Zn-Pb矿化带成矿体系中有大量蒸汽加热酸性地下水的混入，这种酸性地下热水在矿床上部产生了大量高岭石化和重晶石化等酸性蚀变，并且在下渗过程中与上升含矿热液混合，使含矿热液体系的物理化学条件发生急剧变化，各种矿物同时达到饱和或过饱和而快速沉淀，从而阻碍了矿区北部矿化分带的进一步发育，并导致了矿物环带构造的大量出现甚至胶状矿物的形成。 |
| 中文关键词:矿物共生序列 成矿流体演化 银山矿床 江西 |
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| Reidentification of mineral associations in the Yinshan polymetallic deposit fo Jiangxi Province and their genetic implications |
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| Abstract:The Yinshan polymetallic deposit located in the Jiangnan Proterozoic island arc is a large size Cu-Pb-Zn deposit associated with Au and Ag of significant economic value. Genetically, it has a close relation to the I-type Mesozoic volcanism, The Yinshan deposit is characterized by its unsymmetric ore zoning with the Cu (Au) mineralization at the center of the geothermal system. From the geothermal center southward to Nahshan area, Cu(Au), Cu-Pb-Zn, Pb-Zn and Pb-Ag mineral zones are recognized in succession, with the corresponding mineral sequence being quartz + pyrite + quartz + chalcopyrite + sphalerite ± enargite ± pyrite ± chloritc →quartz + sphalcrite + pyritc ± chlorite→quartz + sphalcritc + sidcrite ± chloritc→ siderite + chlorite + galena + argentite ± quartz ± native silver. Comb structure composed of euhedral and subhedral crystals of quartz or siderite are frequently found; impurities in the hydrothermal minerals are low, and the vein-related alteration is rather intense. These features suggest that the ore veins at the center and in the southern part of the Yinshan deposit must have been developed in a gradually evolving hydrothermal system. However, to the north of the geotherrnal center is the Jiuqu Zn-Pb mineralized zone with indistinct further mineralization zoning, which is characterized by the appearance of pyrite + siderite and zonal sphalerite and siderite as well as frequently-seen colloform pyrite. The colloform pyrite is partly replaced by sphalerite and must have been formed in a pyrite-oversaturated solution. It is suggested that mineralization of the Jiuqu Zn-Pb zone took place in a drastically changing physicochemical environment, in which several minerals would become saurated or oversaturated simultaneously. Moreover, kaolinization and baritization are frequently found in the upper part of the Yinshan deposit, especially in the Jiuqu Zn-Pb mineralized zone. They were produced by acidic leaching of steam-heated groundwater. As the acidic groundwater descended along its path, it mixed with the ascending hydrothermal fluid rich in ore-forming elements to cause an abrupt change of the physicochemical condition of the hydrothermal system and a rapid deposition of many ore minerals, but it itself brought almost no ore-forming elements. This might have been the case for the mineralization of the Jiuqu Zn-Pb zone. |
| keywords:mineral sequence, evolution of ore fluid, the Yinshan deposit in Jiangxi Province |
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