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文摘
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陕西八方山大型(金)多金属矿床赋存在于中泥盆统吉维特晚期的热水沉积岩相中。富SiO2酸酐型热水同生—交代沉积作用形成热水同生沉积微相(层状硅质岩)、热水同生交代微相(微晶石英岩及硅化灰岩)；富Fe^2+ - Mg^2+碳酸盐型热水同生沉积作用形成层状含铜硅质铁白云岩；在同生断裂附近，因热水液压致裂-隐爆作用形达含铜黄铁矿硅质铁白云石角砾岩；富Na^+铝硅酸盐型／富Fe^2+、Mg^2+碳酸盐型热流体在同生断裂中形成热水充填微相(穿层脉状钠长石碳酸岩)；低温热卤水(富F、Ba、B、As、Sb)形成热卤水同生沉积微相。矿质大规模沉淀的地球化学动力学因素为：在热水沉积成矿盆地中，在单一成分热水体系的温度、压力改变而发生快速化学沉淀；不同成分、性态的热水混合后，强烈的酸—碱作用及Eh-pH剧变等，触发热水体系失稳，引起矿质大规模沉积。[SiO2]和F可能是重要的矿化剂。 |
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其他语种文摘
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The Bafangshan polymetallic deposit occurs in the Middle Devionian Fengtai apart-pull basin. Based on its sedimentology, mineralogy, petrology and geochemistry of the deposit ,the geological -geochemical characteristics of hydrothermal facies are described.Six patterns of these hydrothermal lithofacies were defined.i.e., hydrothermal synsedimentation microfacies, hydrothermal syn-sedimentation-replacement microfacies, mixing hydrothermal syn-sedimentation microfacies, hydrothermal explosion and fluid pressure-fracturing microfacies, hydrothermal filling-replacement microfacies and hot-brine syn-sedimentary microfacies.Silicates with(FeO+Fe_2O_3+MgO) accounting for less than 10% and SiO_2＞70% may have resulted form hydrothermal syn-sedimentation. Siliecous ferrodolomities with (FeO+Fe_2O_3+MgO) accounting for more than 20% and SiO_2 30%to 50% were also derived form hydrothermal syn-sedimentation in the subbasin. Ferrodolomitites were produced by Fe-Mg-Ca-rich carbonate-type hot water.Polymetallic ores were accoumulated as a result of mixing of different components. Ore-forming materials were deposited in response to extensive chemical reactions.F and [SiO_2]in hydrothermal fluids could serve as the mineralizers mainly responsible for the transport of metallogenic materials. |
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来源
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矿物学报
,2003,23(1):75-81 【核心库】
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关键词
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多金属矿床
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热水沉积岩相
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热水同生沉积微相
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热水同生交代微相
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矿化剂
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地址
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1.
中国科学院地球化学研究所, 矿床地球化学开放研究实验室, 550002
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西北有色金属地质勘查局, 陕西, 西安, 710068
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中国科学院地球化学研究所, 矿床地球化学开放研究实验室
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有色金属矿产地质调查中心, 北京, 100814
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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1000-4734 |
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学科
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地质学 |
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基金
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国家重大基础研究规划项目（2001CB409805）
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国家自然科学基金国家杰出青年科学基金
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文献收藏号
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CSCD:1279560
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