| 西秦岭纳合尔金矿床成因——来自毒砂矿物化学及硫同位素特征的证据 |
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| 关键词:arsenopyrite major and trace elements sulfur isotopes principal component analysis Nahe’er gold deposit West Qinling |
| 基金项目:本文由深地国家科技重大专项课题(编号: 2025ZD1009600)、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)、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“甘肃省夏河县纳合尔金矿普查”(编号: 202202-D02; 202401-D02)、中国地质调查局地质调查项目(编号: DD2026021101)联合资助。 |
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| Genesis of the Nahe’er Gold Deposit in the West Qinling Orogen: Constraints from Arsenopyrite Mineral Chemistry and Sulfur Isotope Signatures |
| The Nahe’er gold deposit is a medium-sized gold deposit recently discovered through exploration in the Xiahe–Hezuo ore cluster of the West Qinling region, whose genesis remains unclear. The deposit hosts an abundance of gold-bearing minerals such as arsenopyrite, which can be divided into independent euhedral arsenopyrite (Apy1) and arsenopyrite coexisting with pyrite (Apy2), further classified into arsenopyrite in quartz veins (Apy1b, Apy2b) and arsenopyrite in host rocks (Apy1a, Apy2a). These characteristics are key to unraveling the deposit's genesis. This study systematically investigates the mineral chemistry, in-situ sulfur isotope composition, and geothermometry of arsenopyrite through core logging, ore microscopy, electron probe microanalysis (EPMA), and laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). Additionally, principal component analysis (PCA) was employed to compare the chemical composition of arsenopyrite from the Nahe’er gold deposit with that of arsenopyrite from various global gold deposit types.The results show that Apy2b arsenopyrite is relatively enriched in Ag, Au, Bi, Cr, Mn, and other elements, with Au existing in the arsenopyrite lattice as lattice-bound gold or solid solution (Au+). In-situ sulfur isotope analysis yielded δ3?S values ranging from –17.51‰ to –3.74‰, indicating that the sulfur was primarily derived from metamorphically deformed wall rocks. The estimated formation temperature (326.2~392.5 °C), suggesting a medium- to high-temperature, relatively reduced metamorphic fluid environment. The deposit is classified as an orogenic gold deposit associated with magmatic-hydrothermal activity. Furthermore, the concentrations of Co, Ni, Ag, Bi, Au, and Sb in arsenopyrite can effectively distinguish between orogenic and Carlin-type gold deposits. |
| WEI Lili,TANG Juxing,ZOU Bing,LI Faqiao,LIU Jie,XIONG Yan,ZHANG Qi,MENG Wuyi,WANG Qi,HUANG Shenchuan,DANZENG Zongzhui.2026.Genesis of the Nahe’er Gold Deposit in the West Qinling Orogen: Constraints from Arsenopyrite Mineral Chemistry and Sulfur Isotope Signatures[J].Acta Geoscientica Sinica,47(5):1133-1149. |
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