投稿时间：2024-11-17
修订日期：2025-08-25
网络发布日期：2025-10-31
中文摘要:钟姑（钟九-姑山）矿田位于长江中下游成矿带宁芜盆地南部，是中国重要的铁矿资源储备区。文章通过分析钟姑矿田内姑山、白象山、和睦山3个典型铁矿床中磁铁矿的主量、微量元素的地球化学特征，并结合磁铁矿镁温度计分析，定量估算了磁铁矿的结晶温度，并以此探讨了成矿流体性质。结果表明，磁铁矿具有复杂的环带结构，其微量元素（Ca、Al、Mn、Ti、V）分布显示出岩浆-热液过渡特征，结晶温度范围为400~820°C，且从核部到边部呈现震荡变化，指示成矿流体经历了多次补给与演化。结合前人硫同位素和流体包裹体的研究结果，笔者认为蒸发岩层提供的挥发分（Na+、Cl-、SO42-等）在成矿过程中起到关键作用，促进了铁的迁移和沉淀，并提出熔盐流体在岩浆-热液转换阶段的参与是钟姑矿田火山岩型铁矿（IOA型，即铁氧化物-磷灰石矿床）形成的关键机制，其成矿模式与全球IOA型矿床一致，表现为“岩浆-蒸发岩-热液”三元耦合特征。这一研究为深刻认识宁芜矿集区的成矿规律提供了重要依据。
中文关键词:磁铁矿镁温度计 铁氧化物-磷灰石矿床 蒸发岩 钟姑矿田
Abstract:The Zhonggu (Zhongjiu-Gushan) ore field, located in the southern part of the Ningwu Basin within the Middle-Lower Yangtze River metallogenic belt, is a significant iron ore resource reserve area in China. This study analyzes the major & trace element geochemical characteristics of magnetite from three typical iron deposits in the Zhonggu ore field—Gushan, Baixiangshan and Hemushan, and applies Mg-in-magnetite thermometry to quantitatively estimate the crystallization temperature of magnetite, thereby providing insights into the nature of the ore-forming fluids. The results revealed complex zoning patterns in magnetite, with trace element (Ca, Al, Mn, Ti, V) distributions indicating a magmatic-hydrothermal transitional signature. Crystallization temperatures range from 400 to 820°C, exhibiting oscillatory variations from core to rim, suggesting multiple episodes of fluid replenishment and evolution. Combined with previous sulfur isotope and fluid inclusion studies, the involvement of evaporite-derived volatiles (Na+, Cl-, SO42+) is identified as a critical factor in facilitating iron migration and precipitation. The participation of molten salts during the magmatic-hydrothermal transition is proposed as a key mechanism controlling the formation of volcanic-hosted iron deposits (IOA-type, iron oxide-apatite) in the Zhonggu ore field, consistent with the global “magmatic-evaporite-hydrothermal” tripartite mineralization model for IOA deposits. These findings enhance the understanding of mineralization processes in the Ningwu ore district and provide valuable insights into the metallogenic model of IOA-type iron deposits in the Middle-Lower Yangtze River metallogenic belt.
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基金项目:本文得到国家重点研发计划（编号：2022YFC2903703）和中央高校基本科研业务费“深时数字地球”中央高校科技领军人才团队项目（编号：2652023001）项目资助
引用文本：
钱祥,侯通,王旭东,秦婧怡,王思佳,杨博为,余跃洋.2025.宁芜盆地钟姑矿田火山岩型铁矿床磁铁矿成因及其地质意义[J].矿床地质,44(5):969~982QIAN Xiang,HOU Tong,WANG XuDong,QIN JingYi,WANG SiJia,YANG BoWei,YU YueYang.2025.Genesis of magnetite in volcanic-hosted iron ores of Zhonggu ore field in Ningwu Basin and its geological significance[J].Mineral Deposits44(5):969~982
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