| 北祁连山西段剪切带型金矿床成矿流体特征 |
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| 引用本文：.2000.Fluid inclusions of shear zone type gold deposits in the western part of north Qilian Mountain[J].Mineral Deposits,19(1):9~16 |
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| 基金项目:国家杰出青年基金（编号：49825103）和国家计委科技找矿项目（编号：JG9471902） |
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| 中文摘要:北祁连山西段金矿床以剪切带型为主，控矿的主导因素是剪切构造和成矿流体。对寒山、鹰嘴山和珠龙等代表性矿床的流体包裹体的研究表明，产于剪切带中金矿床的成矿流体具有中低温、低密度和低盐度等特点，包裹体中气体和液体CO2/H2O比值较高。稳定同位素研究结果表明，不同矿床的成矿流体来源不尽相同，鹰嘴山矿床和寒山矿床成矿流体来源以深部流体为主，珠龙矿床的成矿流体主要为大气降水。 |
| 中文关键词:金矿床 成矿流体 成矿机制 北祁连山 |
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| Fluid inclusions of shear zone type gold deposits in the western part of north Qilian Mountain |
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| Abstract:In the past severalyears, morethan a dozen of gold deposits and gold occurrences, such as Hanshan, Yingzuishan, Changma, Hongkouzi and Zhulong, have been discovered in the western part of North Qilian Mountain. All the deposits are of shear zone type and are developed along a group of WNW-striking shear zones. Micro-thermometric measurements were made on quartz- and calcite-hosted inclusions. All of the fluid inclusions in two phases ( vapor+ liquid with V/L ratios of 5% ~10%) and minor amounts of liquid phase hosted in both quartz and calcite are very small, ranging from l to 15 μm. Their homogenization and salinity are 170~ 310℃ and 5. 4% ~ 10. 5% NaCl for Hanshan, 175~ 355℃ and 3. 8% ~ 9. 3% NaCl for Yingzuishan, 115~ 155℃ and l.4%~ 7.7% NaCl for Zhulong, and 85~ 215℃ and 4. 0% ~ 9. 4% NaCl for Changma. In general, the hydrothermal fluids, which are genetically responsible for the gold deposits in the western part of the Qilian Mountain, are characte rized by low to middle temperatures and low salinity. A few measurements for the com position of the single fluid inclusions indicate that both liquid and vapor are ofhigh CO2/H2O ratio. Sulfur isotope data of the Hanshan gold deposit range from -1.9% ~ to 1.7% . With high peak at 0% ~ 0. 5% in histogram. Oxygen isotope data of the hydrothenual fluids (δ18OH2O) change greatly in different deposits or gold occurrences. They are 7. 7% ~ 4. 7%, 7. 4% ~3.6%, 2. 0% and -3. 8% ~ 3.4% in Hanshan, Yingzuishan, Hongkouzi and Zhulong, respectively, which pethaps suggest that the magmatic fluids or the mantle fluids mixed increasingly with meteoric water from Hanshan, Yinzuishan, Hongkouzi to Zhulong during m ine ralization. Inview of the absence of m agmatic activities during the gold mineralization together with the sulfur isotopic evidence and strong enrichment Of CO2, it is concluded that the hydrothermal fluids responsible for the gold mineralization in the western part of the Qilian Mountain are possibly derived from themantle along the deep faults. |
| keywords:gold deposit, shear zone type, fluid inclusion, North Qilian Mountain |
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