| 小秦岭大湖金钼矿床地质特征及成矿流体 |
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| 引用本文： | 郭云成,刘家军,尹超,郭梦需. 小秦岭大湖金钼矿床地质特征及成矿流体[J]. 现代地质, 2021, 35(6): 1536-1550. DOI: 10.19657/j.geoscience.1000-8527.2021.116 |
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| 作者姓名： | 郭云成 刘家军 尹超 郭梦需 |
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| 作者单位： | 1.中国地质调查局 烟台海岸带地质调查中心,山东 烟台 2640002.中国地质大学(北京) 地球科学与资源学院,北京 1000833.中国地质大学 地质过程与矿产资源国家重点实验室,北京 100083 |
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| 基金项目： | 国家自然科学基金重大研究计划重点项目(92062219);国家自然科学基金重点项目(41730426);中国地质调查局项目“胶西北地区金矿资源勘查”(DD20208006) |
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| 摘 要： | 小秦岭地区位于华北克拉通南缘,赋存许多大型-超大型的金矿床,大湖金钼矿床位于小秦岭北矿带.大湖金钼矿床成矿具有多期多阶段特点,包括热液期和表生期,根据矿脉穿切关系、矿石的矿物组成以及结构、构造研究,热液期分为4个成矿阶段,即石英-钾长石-辉钼矿阶段(Ⅰ)、石英-黄铁矿-自然金阶段(Ⅱ)、石英-多金属硫化物-自然金阶段(...
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| 关 键 词： | 小秦岭 大湖金钼矿床 流体包裹体 氢氧同位素 造山型金矿床 |
| 收稿时间： | 2021-05-19 |
| 修稿时间： | 2021-10-30 |
Geological Characteristics and Ore-forming Fluids of the Dahu Au-Mo Deposit in Xiaoqinling Gold Field |
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| GUO Yuncheng,LIU Jiajun,YIN Chao,GUO Mengxu. Geological Characteristics and Ore-forming Fluids of the Dahu Au-Mo Deposit in Xiaoqinling Gold Field[J]. Geoscience of Geosciences, 2021, 35(6): 1536-1550. DOI: 10.19657/j.geoscience.1000-8527.2021.116 |
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| Authors: | GUO Yuncheng LIU Jiajun YIN Chao GUO Mengxu |
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| Affiliation: | 1. Yantai Center of Coastal Zone Geological Survey,China Geological Survey,Yantai,Shandong 264000,China2. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083,China3. State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083,China |
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| Abstract: | The Xiaoqinling district, located on the southern margin of the North China Craton, is the second largest gold province in China.The Dahu is a typical Au-Mo deposit on the northern margin of the Xiaoqinling terrane, and is hosted by migmatitic granites and biotite-plagioclase gneiss of the Taihua supergroup metamorphic complex.According to crosscutting relationships and mineral assemblages, the hydrothermal ore-forming process can be divided into four stages, including quartz-K-feldspar-molybdenite assemblage(Ⅰ), quartz-pyrite-molybdenite assemblage(Ⅱ), quartz-pyrite-polymetallic sulfide assemblage(Ⅲ), and quartz-calcite assemblage(Ⅳ).Petrographic, fluid inclusion microthermometric and micro-Raman spectroscopic analyses reveal three types of fluid inclusions in quartz, i.e., CO2-H2O (C-type), H2O-solution (W-type), and pure CO2(PC-type). Stage Ⅰ quartz mainly contains C-type, PC-type, and W-type inclusions.Homogenization temperatures of C-type inclusions vary from 275.3 to 350.0 ℃ with salinity of 6.3% to 14.7%, and have δ18Owater values from 4.6‰ to 5.9‰ and δD values from -82‰ to -63‰.Stage Ⅱ quartz mainly contains C-type inclusions with small amounts of PC-type and W-type inclusions.Their C-type inclusions homogenized at 260.0 to 312.7 ℃, lower than that of stage Ⅰ.The fluid salinities vary from 2.2% to 17.5%.The fluids have δ18Owater values from 3.0‰ to 4.5‰ and δD values from -90‰ to -50‰.Maximum trapping pressure estimated from the CO2-H2O inclusions are 196 MPa for stage Ⅱ, corresponding to 7.1 km depth.The ore-forming fluid is characterized by meso- to hypothermal, CO2-rich and low salinity, resembling typical metamorphic fluids.Hydrogen-oxygen isotope signatures indicate that the fluids were originated from metamorphic devolatilization.The reactions of metamorphic fluid with the wallrocks may have led to the isotope exchange.Therefore, the Dahu Au-Mo deposit is best classified to be an orogenic-type gold deposit. |
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| Keywords: | Xiaoqinling district Dahu Au-Mo deposit fluid inclusion H-O isotope orogenic gold deposit |
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