Molybdenum speciation in magmatic-hydrothermal fluids: Constraints from molybdenite solubility experiments and thermodynamic modeling
文献类型：期刊论文
| 作者 | Fang, Jing2,3; Audetat, Andreas3; Dolejs, David1 |
| 刊名 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| 出版日期 | 2025-04-15 |
| 卷号 | 395页码:95-111 |
| 关键词 | Molybdenum speciation Molybdenite solubility Magmatic-hydrothermal fluids Synthetic fluid inclusions Thermodynamic modeling Porphyry Mo deposits |
| ISSN号 | 0016-7037 |
| DOI | 10.1016/j.gca.2025.01.032 |
| 通讯作者 | Fang, Jing(kfangjing@126.com) |
| 英文摘要 | Magmatic-hydrothermal ore deposits are the world's major source of molybdenum (Mo), yet the speciation of Mo in magmatic-hydrothermal fluids is still uncertain. We experimentally measured the solubility of molybdenite (MoS2) in H2O-S-NaCl +/- HCl fluids at 800 degrees C, 200 MPa, with oxygen fugacity (fO(2)) controlled at similar to Ni-NiO + 1 (similar to NNO + 1), Re-ReO2 (RRO), MnO-Mn3O4 (MMO) and Fe3O4-Fe2O3 (HM) buffers. A relatively simple fluid system was chosen to facilitate thermodynamic interpretation of the experimental results. The fluids were first allowed to equilibrate with MoS2 for 48 - 72 h before they were sampled in-situ by means of synthetic fluid inclusions in quartz and finally analyzed by laser ablation ICP-MS. In the HM-, MMO- and sulfur-free RRO-buffered experiments, Mo oxides were identified in the run products. Molybdenum concentrations in the fluids of these experiments are very high, reaching up to 47,000 mu g g(-1), and they are independent of fO(2) and the sulfur content of the fluid. In contrast, Mo concentrations in the fluids of the Mo oxide-free experiments (i.e., all similar to NNO + 1-buffered experiments and the sulfur-bearing RRO-buffered experiments) vary from 33 to 11,000 mu g g(-1) and increase with decreasing sulfur content of the fluid (5.0 to 0.5 wt% sulfur), increasing fO(2) (similar to NNO + 1 to RRO buffer), decreasing HCl content (1.0 to 0.02 molality of HCl), and increasing NaCl content (0.1 to 5 molality of NaCl), except for the most saline and two HCl-enriched fluids investigated. Thermodynamic calculations and interpretations were performed for all Mo oxide-free experiments to check whether the observed MoS2 solubility trends fit with any of the Mo species that have been previously proposed to be relevant in magmatic-hydrothermal fluids. The results suggest that NaHMoO40, NaHMoO3S0, H2MoO2S20 and/or NaHMoO2S20 species may dominate in low-salinity (<= 1 molality of NaCl), HCl-poor (<= 0.13 molality of HCl) fluids, NaMoO3Cl0 in more saline and/or HCl-rich fluids, and NaHMoO2S20 in extremely sulfur-rich (>= 20 wt% sulfur) fluids. For natural fluids exsolving from metaluminous to peraluminous magmas NaMoO3Cl0 is the most relevant Mo-bearing species. An empirical equation that predicts the Mo content of molybdenite-saturated fluids as function of temperature (T), pressure (P), fluid salinity, fO(2), sulfur fugacity (fS(2)) and pH is provided. Mo concentrations measured in natural fluid inclusions agree well with predicted MoS2 solubilities. In natural Climax-type porphyry Mo systems, fluid cooling and decompression are probably the most important driving forces for MoS2 precipitation, as fluid-rock interaction (leading to lower HCl in the fluid) and mixing with meteoric water (leading to lower NaCl, HCl and sulfur content and to higher fO(2)) enhance the MoS2 solubility rather than decrease it. |
| WOS关键词 | PARTIAL MOLAL PROPERTIES ; PORPHYRY MO DEPOSITS ; HIGH-TEMPERATURES ; HIGH-PRESSURES ; DEGREES-C ; AQUEOUS-SOLUTIONS ; REDOX REACTIONS ; SILICATE MELTS ; OXYGEN BUFFER ; STRUCTURAL ENVIRONMENTS |
| 资助项目 | Youth Innovation Promotion Association of Chinese Academy of Sciences[2020212] ; Sino-Germany (CSC-DAAD) Postdoctoral Scholarship |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001465618300001 |
| 出版者 | PERGAMON-ELSEVIER SCIENCE LTD |
| 源URL | [http://ir.qdio.ac.cn/handle/337002/201635]  |
| 专题 | 海洋研究所_深海极端环境与生命过程研究中心 |
| 通讯作者 | Fang, Jing |
| 作者单位 | 1.Univ Freiburg, Inst Earth & Environm Sci, D-79104 Freiburg, Germany 2.Chinese Acad Sci, Inst Oceanol, Ctr Deep Sea Res, Ctr Ocean Mega Sci, Qingdao 266071, Peoples R China 3.Univ Bayreuth, Bayer Geoinst, D-95440 Bayreuth, Germany |
| 推荐引用方式 GB/T 7714 | Fang, Jing,Audetat, Andreas,Dolejs, David. Molybdenum speciation in magmatic-hydrothermal fluids: Constraints from molybdenite solubility experiments and thermodynamic modeling[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2025,395:95-111. |
| APA | Fang, Jing,Audetat, Andreas,&Dolejs, David.(2025).Molybdenum speciation in magmatic-hydrothermal fluids: Constraints from molybdenite solubility experiments and thermodynamic modeling.GEOCHIMICA ET COSMOCHIMICA ACTA,395,95-111. |
| MLA | Fang, Jing,et al."Molybdenum speciation in magmatic-hydrothermal fluids: Constraints from molybdenite solubility experiments and thermodynamic modeling".GEOCHIMICA ET COSMOCHIMICA ACTA 395(2025):95-111. |
入库方式： OAI收割
来源：海洋研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。