| 西秦岭纳合尔金矿床黄铁矿矿物化学特征及地质意义 |
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| 引用本文：熊妍,唐菊兴,李发桥,杨涛,刘杰,邹兵,韦利莉,孟五一,尹青青,王琦,张琪.2026.西秦岭纳合尔金矿床黄铁矿矿物化学特征及地质意义[J].地球学报,47(5):1079-1096. |
| DOI：10.3975/cagsb.2026.063001 |
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| 基金项目:本文由深地探测与矿产勘查全国重点实验室开放课题(编号: KFDM2025208)、中国地质科学院矿产资源研究所基本科研业务费专项经费(编号: KK2513)、深地国家科技重大专项课题(编号: 2025ZD1009600)、甘肃省地矿局院士专家工作站项目(编号: GSDKAEW2024)、甘肃省地勘基金项目(编号: 202202-D02; 202401-D02)和中国地质调查局地质调查二级项目(编号: DD2026021101)联合资助。 |
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| 中文摘要:西秦岭造山带是中央造山带的重要组成部分, 也是我国重要的金成矿带之一。纳合尔金矿床地处西秦岭造山带西北部, 是紧邻加甘滩金矿的一个中型金矿床, 该矿床的成因类型、成矿物质来源及成矿机制尚不清楚。本文通过野外地质调查与钻孔编录, 对01排钻孔的黄铁矿样品进行了电子探针主量元素、LA-ICP-MS微量元素以及原位硫同位素测试。研究结果显示, 纳合尔黄铁矿根据产出状态可分为四类: 草莓状(Py0)、与其他矿物共生(Py1)、脉状(Py2)和自形-他形粒状(Py3)黄铁矿。各类黄铁矿中Co/Ni比值逐渐降低, 反映成矿温度的降低。黄铁矿硫同位素δ34S值介于–17.31‰~3.84‰, 成矿流体以岩浆热液为主, 可能混合了围岩地层。金的赋存状态以晶格金为主, 主要富集在Py1和Py2中, 富集机制与早期形成的黄铁矿和成矿流体的相互作用关系密切。综上分析, 初步判断纳合尔矿床为热液叠加的造山型金矿, 在空间上矿床西南部西侧的钻孔更富集金, 指示找矿潜力由东到西逐渐增强, 可能反映流体的运移路径, 可作为下一步勘查的重点方向。 |
| 中文关键词:黄铁矿 电子探针 LA-ICP-MS 地球化学 金矿床 西秦岭 |
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| Mineralogical and Chemical Characteristics and Geological Significance of Pyrite in the Nahe’er Gold Deposit, West Qinling |
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| Abstract:The West Qinling Orogenic Belt, part of the Central Orogenic Belt, is one of the most important gold metallogenic belts in China. The Nahe’er deposit lies northwest of the West Qinling Orogenic Belt; this is a medium-sized gold deposit adjacent to the Jiagantan gold deposit. The genesis, source of ore-forming materials, and mineralization mechanisms of the Nahe’er deposit remain unclear. Based on field geological investigations and detailed drillhole geological logging, electron probe microanalysis of major elements, LA-ICP-MS trace elements, and in situ sulfur isotope analyses were conducted on pyrite from representative drillholes in the No.1 exploration line of the deposit. Pyrite can be classified into four types based on its form of occurrence: framboidal (Py0), pyrite associated with other minerals (Py1), vein-type (Py2), and euhedral-anhedral (Py3). The results indicate that the Co/Ni ratio decreased gradually across the various pyrite types, reflecting a lower mineralization temperature. The δ34S values of pyrite range from –17.31‰ to 3.84‰. The ore-forming fluids are predominantly magmatic and hydrothermal, possibly mixed with fluids from the wall-rock strata. Gold is predominantly present in the form of lattice gold, mainly enriched in Py1 and Py2, and this enrichment is closely related to the interaction between the early-formed pyrite and ore-forming fluids. Based on the above analysis, it can be preliminarily concluded that the Nahe’er deposit is an orogenic gold deposit with hydrothermal overprinting. Spatially, drill holes on the western side of the southwestern part of the deposit showed higher Au concentrations, indicating that exploration potential increased gradually from east to west; this may reflect fluid-source pathways and should be prioritized as a key direction for future exploration. |
| keywords:pyrite EPMA LA-ICP-MS geochemistry gold deposit West Qinling |
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