| 向开义,田世洪,刘嘉文,龚迎莉,李海东,黄昌祺,梁正伟,耿显雷,谷泽博.粤北下庄花岗岩岩石成因与铀成矿之间的关系[J].矿产勘查,2026,2(2):310-324 |
| 粤北下庄花岗岩岩石成因与铀成矿之间的关系 |
| Relationship between the genesis of the Xiazhuang granite and uranium mineralization in the Xiazhuang uranium deposit, northern Guangdong |
| 投稿时间：2025-11-27 |
| DOI：10.20008/j.kckc.202602009 |
| 中文关键词: 富铀花岗岩 岩石成因 成矿模型 锆石 U-Pb定年 全岩主微量元素 Nd同位素 |
| 英文关键词: uranium-rich granite petrogenesis ore-forming model zircon U-Pb dating whole-rock majorand trace elements Nd isotopes |
| 基金项目:本文受中国铀业有限公司—东华理工大学核资源与环境国家重点实验室联合创新基金(2022NRE-LH-05)铀资源探采与核遥感全国重点实验室自主部署项目(2024QZ-TD-03，2025QZ-YZZ-07-01)，江西省“双千计划”创新领军人才长期项目(20201，01003)，江西省自然科学基金重点项目(20224ACB203011)东华理工大学研究生创新基金(YC2024-S484)联合资助。 |
| 作者 | 单位 | | 向开义 | 铀资源探采与核遥感全国重点实验室,江西南昌 330013
东华理工大学地球与行星科学学院,江西南昌 330013 | | 田世洪 | 铀资源探采与核遥感全国重点实验室,江西南昌 330013
东华理工大学地球与行星科学学院,江西南昌 330013
东华理工大学核资源与环境国家重点实验室,江西南昌 330013 | | 刘嘉文 | 铀资源探采与核遥感全国重点实验室,江西南昌 330013
东华理工大学地球与行星科学学院,江西南昌 330013 | | 龚迎莉 | 清华大学能源与动力工程系,北京 100084 | | 李海东 | 中国核工业集团有限公司二九〇研究所,广东韶关 512029 | | 黄昌祺 | 铀资源探采与核遥感全国重点实验室,江西南昌 330013
东华理工大学地球与行星科学学院,江西南昌 330013 | | 梁正伟 | 铀资源探采与核遥感全国重点实验室,江西南昌 330013
东华理工大学核资源与环境国家重点实验室,江西南昌 330013 | | 耿显雷 | 铀资源探采与核遥感全国重点实验室,江西南昌 330013
东华理工大学核资源与环境国家重点实验室,江西南昌 330013 | | 谷泽博 | 铀资源探采与核遥感全国重点实验室,江西南昌 330013
东华理工大学地球与行星科学学院,江西南昌 330013 |
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| 中文摘要: |
| 花岗岩型铀矿在国内铀矿资源总量中占据主导地位。查明富铀花岗岩的岩石成因机理，揭示铀富集的过程可为铀矿找矿勘探工作提供理论指导和科学依据，并为铀成矿模型的系统构建、完善与创新奠定基础。本文对下庄岩体中的新鲜花岗岩、蚀变花岗岩以及铀矿石进行了全岩主微量元素和 Nd同位素分析并对新鲜花岗岩进行了锆石 U-Pb定年。结果显示，下庄新鲜花岗岩成岩年龄为(235.8±2.7)Ma，呈现出高硅(SiO2 =72.7%~78.1%)、高钾(K2O=4.41%~5.63%)、低镁(MgO=0.10%~0.64%)和过铝质(A/CNK=1.05~1.23)的特征；且具有较低的稀土总含量(∑REE=42.3×10-6~270×10-6)负的 Eu异常(Eu/Eu*=0.10~0.34)富集 Rb、U、 K等大离子亲石元素,亏损 Nb、Ta、Zr和 Ti等高场强元素的特，征。此外，新鲜花岗岩具有较低，的 εNd(t)= -10.9~-10.0，较高的 Rb/Sr比值(3.39~68.2)和较低的 CaO/Na2O比值(0.06~0.44)，表明下庄花岗岩来自古元古代变沉积岩部分熔融，经历了较高程度的分离结晶，具有 S型花岗岩特征。蚀变花岗岩、铀矿石具有和新鲜花岗岩相似的微量、稀土元素配分模式和 Nd同位素组成。从新鲜花岗岩到蚀变花岗岩到铀矿石(铀含量平均值分别为 17.2×10-6108×10-61341×10-6)铀含量逐渐上升。根据本文对新鲜花岗岩的锆石定年以及前人对铀矿石的定年发现成，岩成矿年，龄相差大于，70 Ma。综上所述，本文认为下庄花岗岩型铀矿属于后生热液型铀矿床，而矿区内的新鲜花岗岩则为铀元素的富集提供了重要的物质来源。 |
| 英文摘要: |
| Granite-type uranium deposits dominate the total uranium resources in China. Investigating the pet-rogenetic mechanism of uranium-rich granite and revealing the process of uranium enrichment can not only providetheoretical guidance and scientific basis for uranium prospecting and exploration practices but also lay a solid foun-dation for the systematic establishment, improvement and innovation of uranium metallogenic models. This studyconducted whole-rock major and trace element analyses, Nd isotope analyses on fresh granites, altered granites, anduranium ores from the Xiazhuang rock mass, and performed zircon U-Th-Pb dating for the fresh granites. The re-sults show that the fresh granites in Xiazhuang have a crystallization age of (235.8±2.7) Ma, with geochemical char-acteristics as follows: they are characterized by high silica (SiO2=72.7%-78.1%), high potassium (K2O=4.41% -5.63%), low magnesium (MgO=0.10%-0.64%) and peraluminous nature (A/CNK=1.05-1.23). In terms of rareearth elements (REE), they have low total REE contents ( ∑ REE=42.3×10-6-270×10-6) and exhibit Eu depletion(Eu/Eu*=0.10-0.34). For trace elements, they are enriched in large ion lithophile elements such as Rb, U and K,while depleted in high field strength elements including Nb, Ta, Zr and Ti.In addition, the fresh granites exhibit lowεNd(t) values (-10.9 --10.0), high Rb/Sr ratios (3.39-68.2), and low CaO/Na2O ratios (0.06-0.44). These geo-chemical signatures indicate that the Xiazhuang granites were derived from the partial melting of Paleoproterozoicmetasedimentary rocks, experienced a high degree of fractional crystallization, and possess the geochemical charac-teristics of S-type granites. Altered granites and uranium ores share similar trace element, rare earth element (REE)distribution patterns, and Nd isotope compositions with fresh granites. From fresh granites to altered granites to ura-nium ores (with average uranium contents of 17.2×10-6, 108×10-6, and 1341×10-6, respectively), the uranium con-tent shows a gradual increasing trend. Combined with the zircon dating results of fresh granites in this study and pre-vious dating data of altered granites and uranium ores, it is indicated that the time gap between the diagenetic ageand metallogenic age exceeds 70 Ma. In conclusion, this study proposes that the Xiazhuang granite-type uraniumdeposit is an epigenetic hydrothermal uranium deposit, and the fresh granite in the Xiazhuang area serves as a cru-cial material source for uranium enrichment. |
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