| 鲁西归来庄金矿田燕山期金成矿系统及成矿模式 |
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| 引用本文： | 于学峰,李大鹏,单伟,李增胜,耿科,舒磊,孙雨沁,宋英昕.鲁西归来庄金矿田燕山期金成矿系统及成矿模式[J].地质力学学报,2022,28(5):821-841. |
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| 作者姓名： | 于学峰 李大鹏 单伟 李增胜 耿科 舒磊 孙雨沁 宋英昕 |
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| 作者单位： | 1.自然资源部金矿成矿过程与资源利用重点实验室, 山东 济南 250013 |
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| 基金项目： | 国家自然科学基金项目（42272104，42172094，41372086，41672084，41772076，41503038） |
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| 摘 要： | 鲁西归来庄金矿田是中国东部最重要的富碲型金矿田之一，也是鲁西地区迄今唯一的特大型金矿田。矿田中各金矿床受铜石潜火山穹隆控制，产出于不同深度、不同地质构造部位、不同的地质体中，矿化类型多样，但它们的形成环境、成矿地质背景、成矿作用特征总体一致:①归来庄金矿田是一个主要由前寒武纪基底岩石和早古生代碳酸盐岩盖层组成、中生代构造–岩浆作用较为发育的内生中低温热液金矿集区；②燕甘断裂是郯庐断裂带派生构造，控制着区内地层、岩浆岩、次级构造及金矿床/点的展布；燕甘断裂的次级断裂、潜火山穹隆的放射状、环状构造是矿液运移和沉淀聚集的良好场所；③金矿化以隐爆角砾岩型、镁质碳酸盐岩微细浸染型、斑岩型、矽卡岩叠加型及破碎带蚀变岩型为主，矿石普遍发育浸染状、细脉浸染状、网脉状、团块状和块状构造，反映其形成于岩浆期后热液环境；④具有碲与金超常富集共存的显著特征，金属矿物除常见的自然金、银金矿外，另有含碲矿物碲铜金矿、碲金银矿、碲银矿、碲金矿等；⑤早侏罗世中偏碱性岩浆侵位初步启动了该区的金成矿过程，为早白垩世的中碱性岩浆活动提供了母岩和成矿物质来源，早白垩世可能是鲁西归来庄金矿田的主要成矿时期；⑥成矿流体具有低温、低盐度特征，同位素特征具有多来源性，以岩浆水和大气降水为主，并有少量变质水的参与；⑦在成矿热液中可能是Au与Te、S结合生成可搬运的配合物进行运移；成矿热液中有较高的碲逸度，在中低温条件下碲易置换硫而进入硫化物晶格，在高碲逸度的条件下碲则易与Au、Ag、Pb等元素形成碲化物而参与成矿。这种区域上成矿特征表现出的一致性，表明鲁西归来庄地区中生代大规模金成矿作用受控于统一的地质事件，可划归为一个统一的潜火山中—低温热液金成矿系统。
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| 关 键 词： | 隐爆角砾岩 富碲金矿 成矿系统 归来庄 鲁西地区 |
| 收稿时间： | 2022-05-11 |
Yanshanian gold metallogenic system and metallogenic model of the Guilaizhuang gold ore field,western Shandong |
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| Institution: | 1.Key Laboratory of Gold Mineralization Processes and Resource Utilization, MNR, Jinan 250013, Shandong, China2.Shandong Provincial Key Laboratory of Metallogenic Geological Process and Resource Utilization, Jinan 250013, Shandong, China3.Shandong Institute of Geological Sciences, Jinan 250013, Shandong, China |
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| Abstract: | The Guilaizhuang gold ore field is one of the essential tellurium-rich goldfields in eastern China and the only super-large goldfield in western Shandong so far. These gold deposits controlled by the Tongshi subvolcanic dome occur in different depths, geological structures, and geological bodies. Though their mineralization types are diverse, their host wall rocks, formation environment, geological background, and metallogenic characteristics are generally consistent: (1) The Guilaizhuang gold ore field, mainly composed of Precambrian basement rocks and early Paleozoic carbonate cap rocks, is an endogenous medium?low hydrothermal gold concentration area of relatively developed Mesozoic tectonic magmatism. (2) Yangan fault, a derivative structure of the Tanlu Fault Zone, controls the distribution of strata, magmatic rocks, secondary structures, and gold deposits (points) in this area. The sub-faults of the Yangan fault and the radial and circular structures of subvolcanic domes are good places for ore fluid migration and sedimentation. (3) The mineralization types are mainly cryptoexplosive breccia, magnesian carbonate micro-disseminated, porphyry, skarn superposition, and altered fracture zone. The ores generally develop into disseminated, veinlet disseminated, stockwork, crumb, and block structures, reflecting that they were formed in the post-magmatic hydrothermal environment. (4) It shows a distinguished character of coexistence of tellurium and gold super concentration. In addition to common native gold and electrum, there are also tellurium-containing minerals such as bessmertnovite, petzite, hessite, calaverite, etc. (5) The early Jurassic intermediate alkaline magma initially started the gold mineralization process in this area and provided parent rock and material source for the early Cretaceous alkaline magmatic activities. The main mineralization period of the Guilaizhuang gold ore field in western Shandong may be in the early Cretaceous. (6) The ore-forming fluid has the characteristics of low temperature and low salinity. The isotopic characteristics are multi-sourced. They are dominated by magmatic water and atmospheric precipitation, with a small amount of metamorphic water. (7) Au likely combines with Te and S to form transportable complexes for migration in the ore-forming hydrothermal fluid. There is a high tellurium fugacity in the ore-forming hydrothermal fluid. Under medium- and low- temperature conditions, tellurium can easily replace sulfur and enter the sulfide lattice. Under high tellurium fugacity conditions, tellurium is prone to form telluride with elements such as gold, silver and lead to mineralization. The consistency of the regional metallogenic characteristics indicates that the Mesozoic large-scale gold mineralization in the Guilaizhuang area of western Shandong is controlled by a unified geological event and can be classified into a unified subvolcanic medium-low hydrothermal gold metallogenic system. |
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