| 黑钨矿有效沉淀机制:CO2逃逸 |
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| 引用本文： | 刘向冲,张德会.黑钨矿有效沉淀机制:CO2逃逸[J].地质力学学报,2019,25(1):19-26. |
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| 作者姓名： | 刘向冲 张德会 |
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| 作者单位： | 中国地质科学院地质力学研究所,北京100081;中国地质科学院地质力学研究所动力成岩成矿实验室,北京100081;中国地质大学(北京)地球科学与资源学院,北京,100083 |
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| 基金项目： | 中国地质科学院基本科研业务费（JYYWF20180602，DZLXJK201603）；国家自然科学基金（41602088，41402295） |
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| 摘 要： | 黑钨矿是石英脉钨矿床的主要矿石矿物，其沉淀机制一直存在争议。CO2逃逸能否造成黑钨矿有效沉淀尚缺乏定量模型的评价。文章建立了W-Fe-Cl-Na-O-C-H体系的反应平衡模型，涉及22种组分和16个化学反应；相关热力学参数来自SUPCRT数据库。模型计算结果表明，pH与流体压力呈负相关关系，而钨溶解度与流体压力呈正相关关系；当成矿流体压力从静岩压力降至静水压力水平，钨溶解度降幅可达到27%~47%，降幅与温度和深度成正比。因而，降压造成的CO2逃逸是黑钨矿沉淀的有效机制之一。
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| 关 键 词： | 黑钨矿 沉淀机制 CO2逃逸 平衡反应模型 |
| 收稿时间： | 2018/10/11 0:00:00 |
| 修稿时间： | 2018/12/18 0:00:00 |
THE EFFICIENT MECHANISMS FOR PRECIPITATING WOLFRAMITE: CO2 ESCAPING |
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| LIU Xiangchong and ZHANG Dehui.THE EFFICIENT MECHANISMS FOR PRECIPITATING WOLFRAMITE: CO2 ESCAPING[J].Journal of Geomechanics,2019,25(1):19-26. |
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| Authors: | LIU Xiangchong and ZHANG Dehui |
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| Institution: | 1.Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China2.The Laboratory of Dynamic Digenesis and Metallogenesis, Institute of Geomechanics, CAGS, Beijing 100081, China3.School of Earth Sciences and Resources, China University of Geosciences(Beijing), Beijing 100083, China |
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| Abstract: | Wolframite is the main ore mineral of vein-type tungsten deposits. How wolframite precipitates from hydrothermal fluids is highly disputed in the literature. Whether CO2 escaping causes significant precipitationof wolframitehas not been quantitatively examined. A reaction equilibrium model for the system of W-Fe-Na-Cl-H-C-O was established in this contribution. The model contains 22 species and 16 reactions, the thermodynamic data of which are from the database SUPCRT. The modeling results indicate that pH is negatively correlated to fluid pressure and tungsten solubility is positively correlated to fluid pressure. A decreasein fluid pressure from lithostatic to hydrostatic level could cause a drop of tungsten solubility by 27%~47%, and the decrease degree has a positive correlation to temperature and depth. Therefore, CO2 escaping accompanying a drop of fluid pressure is one of the mechanisms precipitating wolframite efficiently. |
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| Keywords: | wolframite precipitation mechanism CO2 escaping equilibrium reaction modeling |
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