摘要
银洞坡金矿床位于河南肖桐柏地区围山城金银多金属矿带内,矿体定位受新元古界歪头山组地层控制。各成矿阶段热液石英中流体的δ^(18)O_w值为0.0‰～10.8‰,晚期碳酸盐中流体的δ^(18)O_W 值为-5.3‰～-9.7‰,流体的δD值为-65‰～-84‰,显示早阶段成矿流体以来自赋矿地层的变质水为主,晚阶段大气降水不断混入。包裹体的δ^(13)C_(CO)_2值介于-3.7‰～+6.7‰,指示流体的碳主体来自碳酸盐储库。硫化物的δ^(34)S 值介于+1.3‰～+3.1‰,具塔式分布特征,硫主要源自围岩歪头山组。^(206)Pb/^(204)Pb=16.540～17.216,^(207)Ph/^(204)Pb=15.056～15.612,^(208)Pb/^(204)Pb=37.336～38.861,显示较明显的铀铅亏损特征,矿石铅ω值介于39.50～48.62,显示铅源的物质成熟度高,为赋矿地层歪头山组,矿石铅同位素与歪头山组地层的一致性及其与南、北秦岭其它构造岩石单元的差异表明,银洞坡金矿的成矿物质主要来自歪头山组地层。无论在成矿流体和物质来源方面,还是在矿床地质特征方面,银洞坡金矿都应属于典型的层控造山型金矿,并形成于扬子与华北大陆板块的碰撞体制。
The Yindongpo gold deposit is located in the Weishancheng Au-Ag-dominated poly-metallic ore belt in the Tongbai Mountains, Henan province. The occurrences of ore bodies are controlled by the ore-hosted strata, i.e. the Neoproterozoic Waitoushan Formation. The δD values of the fluid inclusions within quartz separates from different paragenerations are between - 65‰ and - 84‰, with corresponding δ^18Ow values of 0.0‰ to 10.8‰. The δ^18 OW values of the fluid within late-stage carbonate range from -5.3‰ to - 9.7‰. This indicates that the ore-fluid system was of metamorphic from the ore-hosted strata in early-stage and of meteoric in late- stage. The δ^13 Cco2 values of fluid inclusions vary between - 3.7‰ and ＋6.7‰ , suggesting that the carbon in fluid was likely derived from metamorphic decabonization of carbonate strata. The δ^34 S values of sulfides are ＋ 1.3‰ - ＋ 3. 1‰ and the sulfur may have derived from the Waitoushan Formation. The sulfides have a uniform Pb isotope composition, with ^206pb/^204pb = 16. 540 - 17. 216, ^207pb/^204Pb = 15. 056 - 15. 612 and ^208Pb/^204pb = 37. 336 -38. 861. The ω values of ore lead vary from 39. 50 to 48.62, indicating that the ore-lead source was highly maturized. The ores have similar lead isotope ratios with the Waitoushan Formation but constrasting lead isotope ratios with the other tectonolithologic units of the Qinling Orogen, which strongly suggests that the ore metals were mainly sourced from the Waitoushan Formation. Therefore, the Yindongpo gold deposit is a typical stratabound orogenic-type gold deposit in terms of both its ore-forming fluid and metal source and its geologic characteristics. The ore-forming process took place during continental collision between the Yangtze Block and North China Block.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2006年第10期2551-2560,共10页
Acta Petrologica Sinica
基金
国家自然科学基金项目(40502012
40425006
40352003)
国家重点基础发展规划项目(2006CB403506)
中国科学院百人计划项目的资助
关键词
同位素地球化学
银洞坡金矿床
层控造山型金矿床
桐柏山
大陆碰撞
Isotopic geochemistry, Yindongpo gold deposit, Stratabound orogenic-type gold deposit, Tongbai Mountains, Continental collision
