| 西藏多龙矿集区拿若斑岩型铜(金)矿床锆石和磷灰石地球化学特征及意义 |
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| 引用本文：张荣坤,杨欢欢,董玉杰,王 勤,李 社,李发桥,袁盛朝,翟建军,李宏伟,张 琪,陈守关,付雪莲.2025.西藏多龙矿集区拿若斑岩型铜(金)矿床锆石和磷灰石地球化学特征及意义[J].地球学报,46(4):726-744. |
| DOI：10.3975/cagsb.2024.102601 |
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| 作者 | 单位 | E-mail | | 张荣坤 | 中国地质科学院矿产资源研究所 自然资源部成矿作用与资源评价重点实验室, 北京 100037 | zhangrongkun609@126.com | | 杨欢欢 | 中国地质科学院矿产资源研究所 自然资源部成矿作用与资源评价重点实验室, 北京 100037 | | | 董玉杰 | 西藏自治区地质矿产勘查开发局第五地质大队, 青海格尔木 816000 | 494470932@qq.com | | 王 勤 | 成都理工大学地球与行星科学学院, 四川成都 610059 | | | 李 社 | 中铝西藏金龙矿业股份有限公司, 西藏拉萨 850000 | | | 李发桥 | 中国地质科学院矿产资源研究所 自然资源部成矿作用与资源评价重点实验室, 北京 100037 | | | 袁盛朝 | 中铝西藏金龙矿业股份有限公司, 西藏拉萨 850000 | | | 翟建军 | 中铝西藏金龙矿业股份有限公司, 西藏拉萨 850000 | | | 李宏伟 | 西藏自治区地质矿产勘查开发局第五地质大队, 青海格尔木 816000 | | | 张 琪 | 中国地质大学(北京)地球科学与资源学院, 北京 100083 | | | 陈守关 | 西藏自治区地质矿产勘查开发局第五地质大队, 青海格尔木 816000 | | | 付雪莲 | 成都理工大学地球与行星科学学院, 四川成都 610059 | |
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| 基金项目:国家重点研发计划项目(编号: 2022YFC2905001); 国家自然科学基金项目(编号: 42230813); 中国地质调查局项目(编号: DD20230362); 四川省自然科学基金项目(编号: 2023NSFSC0798)和西藏自治区“十四五”时期科技重大专项(编号: XZ202401YD0006-02) |
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| 中文摘要:拿若大型斑岩型铜(金)矿床是西藏多龙矿集区内重要的矿床之一。前人对该矿床成岩成矿时代、成矿物质来源、成因机制、动力学背景以及保存条件等方面进行了一定的研究, 但对含矿岩浆演化过程的地球化学特征研究较为薄弱。为此, 本文利用LA-ICP-MS方法对拿若矿床含矿岩体的锆石和磷灰石进行成分分析, 开展岩浆结晶分异过程、氧逸度、含水量特征研究, 探讨拿若矿床含矿岩浆演化特征及其对成矿的启示意义。拿若矿床含矿岩浆的锆石具有强正Ce异常和弱-中等负Eu异常, 磷灰石具有强负Eu异常。锆石和磷灰石微量元素特征显示, 拿若矿床的岩浆岩形成于陆缘弧环境, 属I型花岗质岩石。锆石的Th/U、Ce/Sm、Yb/Gd特征显示, 锆石从高温到低温阶段均受到磷灰石和榍石共同结晶的影响。拿若矿床含矿岩浆表现出更高的水含量和氧逸度, 并且含矿岩浆比不含矿岩浆经历了更高的演化程度。富S岩浆发生SO2去气作用及部分岩浆再侵入/混合作用可能是造成含矿岩浆高氧逸度的原因。锆石Dy/Yb<0.2、 10 000×(Eu/Eu*)/Y>7、Ce4+/Ce3+>200能够有效指示岩体含矿性。本文研究结果表明锆石和磷灰石微量元素特征可有效指示岩浆岩的源区特征、结晶历史以及成矿潜力。 |
| 中文关键词:含矿性判别 磷灰石 锆石 矿物地球化学 拿若 多龙矿集区 |
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| Geochemical Characteristics and Significance of Zircon and Apatite in the Naruo Porphyry Cu (Au) Deposit in the Duolong Ore District, Tibet |
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| Abstract:The large-scale Naruo porphyry copper (gold) deposit is one of the important deposits in the Duolong Ore District, Tibet. Although previous studies have examined the diagenetic and metallogenic ages, source of ore-forming materials, genetic mechanism, dynamic background, and preservation conditions of the deposit, the research on geochemical characteristics of the evolution process of ore-bearing magma is still limited. Therefore, in this study, the laser ablation-inductively coupled plasma-mass spectrometry method was used to analyze trace element compositions of zircon and apatite in the ore-bearing rocks of the Naruo deposit. This analysis aimed to study the characteristics of the magma crystallization differentiation process, oxygen fugacity, and water content to explore the evolution characteristics of ore-bearing magmas and their implications for mineralization. Zircons from the ore-bearing rocks of the Naruo deposit showed strong positive Ce and moderate negative Eu anomalies, whereas apatite displayed strong negative Eu anomalies. The characteristics of the zircon and apatite trace elements indicated that the magma was formed in a continental arc environment and belonged to type I granitic rock. The Th/U, Ce/Sm, and Yb/Gd characteristics of zircon showed that zircon is affected by the co-crystallization of apatite and titanite from high temperature to low temperature. The ore-bearing magma of the Naruo deposit exhibited a higher water content and oxygen fugacity and had undergone a higher degree of evolution than the ore-barren magmas. The high oxygen fugacity of ore-bearing magmas may have been caused by SO2 degassing in sulfur-rich magmas and the re-emplacement or mixing of magmas. Zircon Dy/Yb<0.2, 10 000×(Eu/Eu*)/Y>7, and Ce4+/Ce3+>200 can effectively distinguish ore-bearing from ore-barren rocks in the ore district. The results of this study demonstrate that the trace element characteristics of zircon and apatite can effectively indicate the source area characteristics, crystallization history, and ore-forming potential of igneous rocks. |
| keywords:mineralization assessment apatite zircon mineral geochemistry Naruo Duolong Ore District |
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