| 河南栾川县鱼库隐伏钨钼矿床白钨矿元素地球化学特征及其意义 |
| 投稿时间：2024-11-09 修订日期：2024-12-31 点此下载全文 |
| 引用本文：田晓敏.河南栾川县鱼库隐伏钨钼矿床白钨矿元素地球化学特征及其意义[J].地质与勘探,2025,61(1):1-13 |
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| 基金项目:河南省财政地质勘查项目（编号：2024-402)、河南省2023年度科技攻关项目（编号：232102231049）、河南省地质研究院2024年度地质科技攻关“揭榜挂帅”项目（编号：2024-331-XM02）联合资助 |
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| 中文摘要:本文利用阴极发光与LA-ICP-MS分析技术对河南栾川县鱼库隐伏钨钼矿床中的白钨矿W、Mo、Nb、Y、Ho、Yb等元素与矿物结构进行详细分析，以探究该矿床的成矿流体替代机制、流体性质和流体来源。鱼库隐伏钨钼矿床的白钨矿分为三个阶段：早矽卡岩阶段、晚矽卡岩阶段、钾长石-石英-硫化物阶段。分析结果显示，该矿床不同阶段白钨矿稀土元素主要受3Ca2+=2REE3++□Ca (此处“□”指 Ca的空位)的替换机制控制。从早阶段到晚阶段白钨矿REE总量和Mo含量呈递减模式，球粒陨石标准曲线显示各阶段白钨矿的稀土配分模式变化较大：早阶段白钨矿显示海鸥型模式，具有明显的Eu 负异常，轻重稀土分异程度较低，推测早阶段为富F成矿流体；中阶段白钨矿显示轻稀土富集而重稀土亏损的平缓右倾模式，Eu正异常与负异常均有出现，轻重稀土分异程度中等，暗示早阶段白钨矿结晶摄取大量HREE与Mo所致，Eu异常与成矿花岗岩体及水岩反应密切相关；晚阶段白钨矿具有更明显的轻稀土富集、重稀土亏损的右倾模式，Eu弱负异常，暗示晚期流体富Cl。早阶段白钨矿Mo的含量明显高于中阶段与晚阶段，暗示成矿流体为氧化性流体，从早阶段到晚阶段氧化性逐渐减弱。综合分析认为，鱼库白钨矿成矿流体主要来源于晚侏罗世鱼库花岗岩体分异的流体，成矿过程中，水岩交换与流体混合为主要沉淀机制。 |
| 中文关键词:白钨矿 微量元素 成矿流体 鱼库 隐伏钨钼矿床 栾川县 河南省 |
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| Geochemical characteristics of scheelite elements in the Yuku concealed W-Mo deposit of Luanchuan County, Henan Province and their geological significance[ |
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| Abstract:This work attempts to determine the mechanism of fluid substitution, fluid properties, and fluid sources of the Yuku concealed W-Mo deposit in Henna Province. Cathodoluminescence and LA-ICP-MS analytical techniques were utilized to analyze the elements W, Mo, Nb, Y, Ho, Yb in scheelite and the mineral structures of this deposit. The scheelite in the Yuku deposit can be divided into three stages, i.e., early skarn stage, late skarn stage, and potassium feldspar quartz sulfide stage. The analysis results show that the rare earth elements in scheelite at different stages of the deposit were mainly controlled by the replacement mechanism of 3Ca2+=2Re3++□ Ca (where "□" refers to Ca vacancies). From the early stage to the late stage, the total REE and Mo content of scheelite show a decreasing pattern. The standard curves of chondrite meteorites suggest that the rare earth distribution pattern of scheelite varies greatly in each stage. In the early stage, scheelite shows a seagull type pattern, with obvious negative Eu anomalies and low degree of differentiation between light and heavy rare earth elements. It is speculated that the early stage is a F-rich ore-forming fluid. In the middle stage, scheelite displays a gentle right-inclined pattern of light rare earth enrichment and heavy rare earth depletion, with both positive and negative Eu anomalies. The differentiation degree between light and heavy rare earths is moderate, suggesting that the early-stage scheelite crystallization was caused by the uptake of large amounts of HREE and Mo, and Eu anomalies were closely related to the ore-forming granite body and water rock reactions. Late-stage scheelite exhibits a more pronounced right-inclined pattern of light rare earth enrichment and heavy rare earth depletion, with weak negative Eu anomalies, indicative of the late-stage Cl-rich fluid. The Mo content in the early-stage scheelite is significantly higher than that in the middle and late stages, indicating that the ore-forming fluid is an oxidizing fluid, and the oxidizing property gradually weakens from the early stage to the late stage. The comprehensive analysis indicate that the ore-forming fluid of the Yuku scheelite deposit mainly come from the fluid differentiation of the Late Jurassic Yuku granite body. During the mineralization process, water-rock exchange and fluid mixing were the main precipitation mechanisms. |
| keywords:scheelite, trace elements, ore-forming fluid, Yuku, concealed molybdenum-tungsten deposit, Luanchuan County, Henan Province |
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