| 广东长坑大型-超大型金银矿床的地球化学与成因带 |
| 点此下载全文 |
| 引用本文：.1998.Geochemistry and genesis of the Changkeng large-superlarge gold-silver deposit, Guangdong Province[J].Mineral Deposits,17(2):125~134 |
| Hits: 2306 |
| Download times: 1536 |
|
| 基金项目:中国科学院博士点和黄金办科研基金资助项目（921133） |
|
| 中文摘要:对长坑金银矿床的化学组成、同位素特征、流体性质、成矿物理化学条件和机理的系统研究表明，与矿化最密切的硅质岩应主要为热液交代成因；金、银矿体的稀土和微量元素特征既有共性又有异性；矿床的硫、铅、碳、锶同位索组成特征反映它们均为壳源物质或沉积成困；成矿流体相对富Ca、K，主要来自演化了的加热大气水或建造水；矿床形成于中低温的热液条件，矿化机制包括热液沸腾、流体混合与水岩反应。总之，长坑矿床为微细浸染型金矿与碳酸盐岩交代，鸭银矿构成的新颖矿床组合，金、银矿体是统一的热液作用在不同的成矿环境和控矿条件下的产物，它们与区域内的铅锌（银）矿床应属于一个成矿系列。 |
| 中文关键词:金银矿床，热液交代，成矿机理，成矿系列，广东长坑 |
| |
| Geochemistry and genesis of the Changkeng large-superlarge gold-silver deposit, Guangdong Province |
|
|
| Abstract:In the Changkeng gold-silver deposit, SiO2, and Al2O3 contents of mineralized silicified rocks, whose compositions are distributed in both hydrothermal and hydrogenous regions of the Al-Fe-Mn ternary diagram, are 73% t0 95% and l.13% t0 10.44%, respectively. The siliceous gold ores with LREE contents of 33.94×10-6 to 91.86×10-6 are distinctly enriched in LREE, while the LREE enrichment of siliceous silver ores with EREE contents of l.94×10-6 to 45.18×10-6 is lower. Both gold arid silver siliceous ores are rich in As, Sb, Bi, Hg and Ba. In addition, Zn, Pb, Cu contents of the silver ores are also high. The transitional element patterns of ores are similar to those of country rocks. Theδ34S values of sulfides in gold ores vary widely from -35.4‰ to 8.8‰ with an average of -2.4‰, but the δ34S values of sulfides in silver ores are comparatively concentrated, varying from -7.2‰ to 7.3‰, with an average of 2.5‰. The calculated sulfur isotopic composition of the hydrothermal solution is 4‰ to 7‰, and the δ13C values of calcite are -3.23‰ to 0.25‰. The gold ores are enriched in 206Pb with a wide range of 206Pb／204Pb ratio from 18.580 t0 19.885, whereas the silver ores are relatively enriched in 207Pb and 208Pb, with the 207Pb／204Pb ratios being 15.682 to 15.941. Both kinds of ore lead are anomalous lead enriched in radiogenic lead. The sulfur, carbon and lead isotopes of the ore deposit arc crust materials or of sedimentary origin. The δ18O and δD values of the ore-forming solutions derived from evolved heated meteoric waters of formation waters are -5.5‰ to 9. 0‰ and -59‰ to 39‰. The ore-forming solutions mainly contain K+, Ca2+, Na+, Cl- and SO42+ with salinity of 6.0wt% to 15.8wt% NaCl, and the mineralizing temperatures are between 170℃ and 300℃. The metalogenic mechanisms include solution boiling, mixing of fluids, and water-rock interaction. Both siliceous gold ore and silver ore are formed by hydrothermal percolating metasomatism and filling, and hence are products of a unified hydrothermal event in different metallogenic environments and under different ore-controlling conditions. The gold-silver deposit and the Ag-Pb-Zn deposit in this region belong to the same metallogenic series. |
| keywords:gold-silver deposit, hydrothermal metasomatism, ore-forming mechanism, metallogenic serics, Guangdong Province |
| View Full Text View/Add Comment Download reader |
|
|
|
