| 杨 科,樊自春,杨晓飞,李小宇,梁金龙,李 军.西秦岭阳山金矿床黄铁矿标型特征及成矿意义[J].甘肃地质,2024,(3):7-15 |
| 西秦岭阳山金矿床黄铁矿标型特征及成矿意义 |
| Pyrite Typomorphism and Ore Forming Significance in Yangshan Gold Deposit， West Qinling |
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| DOI： |
| 中文关键词: 阳山金矿 黄铁矿 EMPA BSE 标型特征 δFe-δS 晶格金 |
| 英文关键词:pyrite typomorphic pharacteristics δFe-δS lattice gold Yangshan gold deposit |
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| 中文摘要: |
| 阳山金矿床位于西秦岭造山带勉略缝合带中部，矿体主要赋存于中泥盆统碳质碎屑—碳酸盐岩地层中。本文在详细的野外调查和岩相学的基础上，利用电子探针EMPA对矿化千枚岩与矿化斜长花岗斑岩中载金黄铁矿分别进行了原位分析。发现两类黄铁矿在背散射（BSE）图像中均有明显的核—幔—边三世代环带结构，分别对应成矿早期（py1）、主成矿期（py2）、成矿后期（py3）。核部至边部（py1 ～ py3）S和Fe百分含量均呈现先减小后增加的趋势，而As和Au则表现出相反的特征；黄铁矿w（S）／w（Fe） < 1. 148、原子数S／Fe < 2，阳山金矿黄铁矿为贫硫贫铁型黄铁矿并伴随硫亏损；δFe-δS与（Fe + S）-As图解表明阳山金矿为与岩浆热液紧密联系的类卡林型金矿床；As是以As-的形式进入黄铁矿内部替代S，并伴随其他元素替代Fe2+；黄铁矿中金主要以晶格金（Au2+）的形式赋存，同时存在少量纳米级的金颗粒；阳山金矿成矿与晚三叠纪岩浆紧密相关，地下深部岩浆房可能提供了大量成矿物质。 |
| 英文摘要: |
| Yangshan gold deposit is located in the middle of the reluctant-lipped suture zone of the West Qinling orogenic belt, and the ore body is mainly endowed in the carbonaceous clastic-carbonatite strata of the Middle Devonian. In this paper, based on detailed field investigations and petrography, gold-loaded pyrite in mineralized kilomagnetite and mineralized plagioclase granodiorite porphyry were analyzed in situ using electron microprobe EMPA, respectively. Both types of pyrite were found to have obvious core-mantle-edge tri-generation ring structures in backscatter （BSE） images, corresponding to early mineralization（py1）, main mineralization （py2）, and late mineralization （py3）, respectively. The S and Fe percentages from the core to the rim （py1 ~ py3） show a decreasing and then increasing trend, while As and Au show the opposite characteristics; pyrite w（S）／w（Fe） < 1.148, atomic number S／Fe < 2, pyrite in Yangshan gold mine is sulfur-poor and iron-poor pyrite with sulfur loss; δFe-δS and （Fe+S）-As graphs show that Yangshan gold mine is a magmatic hydrothermal linked type of pyrite. The δFe-δS and （Fe+S）-As diagrams indicate that the Yangshan gold ore is a Carlin-like gold deposit closely associated with magmatic hydrothermal fluids; As enters the pyrite as As-to replace S, and is accompanied by the substitution of other elements for Fe2+; the gold in the pyrite ore is mainly in the form of lattice gold（Au+）, and a small amount of nano-sized gold particles exists at the same time; the mineralization of the Yangshan gold ore is closely related to the Late Triassic magma, and the deep underground magma room may provide a large amount of mineralization materials. |
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