| 锆石U-Pb年龄及地球化学特征对成矿作用的指示——以鄂东地区阮家湾钨铜钼矿床为例 |
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| 关键词:Edong district W-Cu-Mo deposit zircon U-Pb zircon geochemistry mineralization |
| 基金项目:地球深部探测与矿产资源勘查国家科技重大专项(编号: 2024ZD1002203); 湖北省自然科学基金项目(编号: 2025AFB351; 2023AFD213); 地质过程与成矿预测全国重点实验室科技部专项经费(编号: GPMR202427); 湖北省地质局项目(编号: KJ2023-60; KCDZ2024-17) |
| 作者 | 单位 | E-mail | | 周润杰 | 湖北省地质调查院, 湖北武汉 430034；资源与生态环境地质湖北省重点实验室, 湖北武汉 430022 | rjzhou@foxmail.com | | 周 豹 | 湖北省地质调查院, 湖北武汉 430034
资源与生态环境地质湖北省重点实验室, 湖北武汉 430022 | 278776817@qq.com | | 文 广 | 中国地质大学(武汉)资源学院, 湖北武汉 430074 | | | 孙 悦 | 湖北国土资源职业学院, 湖北武汉 430090 | | | 吴昌雄 | 湖北省地质局第一地质大队, 湖北大冶 435100 | | | 朱 金 | 湖北省地质调查院, 湖北武汉 430034 | | | 尚世超 | 湖北省地质局第一地质大队, 湖北大冶 435100 | | | 李柏村 | 湖北省地质局第一地质大队, 湖北大冶 435100 | | | 廖 旺 | 资源与生态环境地质湖北省重点实验室, 湖北武汉 430022
湖北省地质科学研究院, 湖北武汉 430034 | | | 宋威方 | 资源与生态环境地质湖北省重点实验室, 湖北武汉 430022；湖北省地质局第六地质大队, 湖北孝感 432000 | | | 刘晓阳 | 湖北省地质调查院, 湖北武汉 430034
资源与生态环境地质湖北省重点实验室, 湖北武汉 430022 | | | 程孝增 | 湖北省地质调查院, 湖北武汉 430034 | |
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| Metallogenic Significance of Zircon U-Pb Age and Geochemical Characteristics: A Case Study of the Ruanjia-wan W-Cu-Mo Deposit in Edong District |
| The Ruanjiawan W-Cu-Mo deposit, situated in the eastern part of the Maopu–Liangjianqiao East–West fault zone in the Edong district, with a proven reserve of 24 000 t WO3, 18 000 t Cu and 2 439 t Mo, is the largest W-Cu-Mo deposit in this region. The Ruanjiawan W-Cu-Mo deposit shows a close association with the occurrence of granodiorites of the region. This study investigates the whole-rock geochemistry, zircon U-Pb geochronology, zircon trace elements, and Hf isotopic composition of the Ruanjiawan granodiorite to constrain its age and petrogenesis and establish the significance of zircon as an indicator of W-Cu-Mo mineralization in the Edong district. Zircon U-Pb geochronology results show that the emplacement age of the Ruanjiawan granodiorite is (143.00±0.74) Ma, corresponding to the Late Mesozoic magmatism and metallogeny in the Edong district. The Ruanjiawan granodiorite has a relatively uniform Hf isotopic composition (εHf(t) = ?5.4 to ?2.2), similar to the zircon Hf isotopic composition of the Tongshankou granodiorite, Tonglüshan quartz diorite, and Longjiaoshan granodiorite. This indicates that these rocks are mainly derived from an enriched lithospheric mantle with minor crustal contamination during magmatic evolution. Zircons from the Ruanjiawan granodiorite exhibit high Eu/Eu* (>0.4) and low Dy/Yb (<0.3) values, suggesting that the magma was relatively hydrous, which is consistent with the water content values (6.85%–8.45%) obtained from the whole rock and composition. Based on trace element analyses of zircons from the Ruanjiawan granodiorite, the calculated magma oxygen fugacity values range from ΔFMQ+1.07 to ΔFMQ+2.88, indicating relatively oxidized conditions. In addition, the zircon Ce4+/Ce3+ ratios range from 93 to 190, which is slightly lower than those from the Tongshankou granodiorite and Tonglüshan quartz diorite. This suggests a relative decrease in the oxidation state of the metallogenic magma from the Tongshankou Cu-Mo deposit to the Tonglüshan Cu-Fe-Au deposit, and subsequently to the Ruanjiawan W-Cu-Mo deposit. The zircon Hf content of the Ruanjiawan granodiorite is negatively correlated with the Ti-in-zircon temperatures, reflecting fractional crystallization during magma evolution and cooling. Ti-in-zircon temperatures range from 660 °C to 727 °C, similar to the crystallization temperatures of zircon in the regional Tongshankou granodiorite and Tonglüshan quartz diorite. This study demonstrates that the trace element compositions of zircon, such as the Eu/Eu*, Dy/Yb, and Ce4+/Ce3+ ratios, are effective indicators of water content characteristics, oxygen fugacity, and magmatic differentiation. Zircon geochemistry and geochronology thus serve as effective means for identifying granitoids with the potential for skarn mineralization. |
| ZHOU Runjie,ZHOU Bao,WEN Guang,SUN Yue,WU Changxiong,ZHU Jin,SHANG Shichao,LI Baicun,LIAO Wang,SONG Weifang,LIU Xiaoyang,CHENG Xiaozeng.2025.Metallogenic Significance of Zircon U-Pb Age and Geochemical Characteristics: A Case Study of the Ruanjia-wan W-Cu-Mo Deposit in Edong District[J].Acta Geoscientica Sinica,46(4):800-814. |
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