太行山南段洪山沟铜金矿床白云母和绿泥石特征及其找矿意义

Characteristics of muscovite and chlorite in Hongshangou copper-gold deposit and its prospecting significance

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DOI 10.20086/j.cnki.yskw.2025.4189
刊名
Acta Petrologica et Mineralogica
年,卷(期) 2025, 44(4)
作者
作者单位

1. 河北省战略性关键矿产研究协同创新中心, 河北地质大学, 河北 石家庄 050031;
2. 河北省战略性关键矿产资源重点实验室, 河北地质大学, 河北 石家庄 050031;
3. 河北省地矿局第九地质大队, 河北 邢台 054000;
4. 内蒙古自治区地质调查研究院, 内蒙古 呼和浩特 010041

摘要
洪山沟斑岩型铜金矿床是洪山多金属成矿区的典型矿床,位于华北克拉通中部南缘山西断隆武安凹陷区,矿体主要赋存于洪山正长斑岩体内。矿化中心及外围白云母和绿泥石十分发育。为探讨洪山沟铜金矿床白云母和绿泥石的成岩成矿意义,运用电子探针(EPMA)、激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)分析了矿床中不同产状和成矿阶段的白云母和绿泥石。结果显示,矿区内绿泥石根据其分布特征可分为3类: 与金属矿物共(伴)生的绿泥石(Chl-1)、由角闪石蚀变而成的绿泥石(Chl-2)及由黑云母蚀变而成的绿泥石(Chl-3)。3种绿泥石均为Fe绿泥石,指示形成于还原环境,其结构中存在Fe对Mg的置换以及Si对Al的置换,表明绿泥石的形成受富Fe、Mg的成矿流体影响,由地质温度计计算出的绿泥石形成温度在112~272℃之间,属于中-低温热液蚀变范围。LA-ICP-MS结果显示完全蚀变的绿泥石更富Cu、Sn、Rb、Zn、Ti、Li、Sr、V、Co、Ni、Sn; 白云母主要有原生白云母(Ms-1)与次生白云母(Ms-2)两类,分别属于普通白云母和多硅白云母。与矿化密切相关的白云母具高Si、Fe低Al的特征,LA-ICP-MS结果显示还原环境下形成的白云母较氧化环境下形成的白云母更富V、W,暗示流体后期有大气降水的混入。综合本文研究成果认为,洪山沟铜金矿床成矿流体早期呈酸性,后期有大气降水的混入并逐渐向中性转变,铜金矿化成矿环境为近中性、还原的中-低温环境,成矿流体富Fe、Mg,贫Si。
Abstract
The Hongshangou porphyry copper-gold deposit is a typical deposit in the Hongshan polymetallic metallogenic area. It is located in the Wu'an depression of Shanxi fault uplift in the southern margin of the central North China Craton. The ore body mainly occurs in the Hongshan syenite porphyry. Muscovite and chlorite are well developed in the mineralization center and periphery. In order to discuss the diagenesis and mineralization significance of muscovite and chlorite in Hongshangou copper-gold deposit, electron probe microanalysis (EPMA) was used to analyze muscovite and chlorite in different occurrences and metallogenic stages of the deposit. The results show that the distribution characteristics of chlorite in the mining area can be divided into three categories: chlorite associated with metal minerals (Chl-1), chlorite altered from hornblende (Chl-2) and chlorite altered from biotite (Chl-3). The three chlorites are all Fe chlorites, indicating that they were formed in a reducing environment. The replacement of Fe to Mg and the replacement of Si to Al in the structure indicate that the formation of chlorites is affected by Fe- and Mg-rich ore-forming fluids. The formation temperature of chlorite calculated by geological thermometer is between 112~272℃, which belongs to the range of medium-low temperature hydrothermal alteration, LA-ICP-MS results show that the completely altered chlorite is richer in Cu, Sn, Rb, Zn, Ti, Li, Sr, V, Co, Ni and Sn. Muscovite mainly includes primary muscovite (Ms-1) and secondary muscovite (Ms-2), which belong to ordinary muscovite and polysilicic muscovite respectively. The muscovite closely related to mineralization has the characteristics of high Si, Fe and low Al, LA-ICP-MS results show that the muscovite formed in the reducing environment is richer in V and W than the muscovite formed in the oxidizing environment, suggesting the mixing of meteoric water in the later stage of the fluid. Based on the research results of this paper, the ore-forming fluid of Hongshangou copper-gold deposit is acidic in the early stage and gradually changes to neutral in the later stage. The ore-forming environment of copper-gold deposit is near neutral and reduced medium-low temperature environment. The ore-forming fluid is rich in Fe, Mg and poor in Si.
关键词
白云母;绿泥石;电子探针;洪山沟铜金矿床;华北克拉通
KeyWord
muscovite; chlorite; electron probe microanalysis; Hongshangou porphyry copper-gold deposit; North China Craton
基金项目
页码 924-948
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王凯迪,张娟*,王红,刘新星,张勇,王丽杰,李若丹,关子琼,薛宇. 太行山南段洪山沟铜金矿床白云母和绿泥石特征及其找矿意义 [J]. 岩石矿物学杂志. 2025; 44; (4). 924 - 948.

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