地球学报2025，Vol.46Issue(4)：800-814,15.DOI:10.3975/cagsb.2024.123001
锆石U-Pb年龄及地球化学特征对成矿作用的指示
Metallogenic Significance of Zircon U-Pb Age and Geochemical Characteristics:A Case Study of the Ruanjiawan W-Cu-Mo Deposit in Edong District
摘要
Abstract
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℃ to 727℃,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.关键词
鄂东地区/钨铜钼矿床/锆石U-Pb/锆石地球化学/成矿作用Key words
Edong district/W-Cu-Mo deposit/zircon U-Pb/zircon geochemistry/mineralization分类
天文与地球科学引用本文复制引用
周润杰,宋威方,刘晓阳,程孝增,周豹,文广,孙悦,吴昌雄,朱金,尚世超,李柏村,廖旺..锆石U-Pb年龄及地球化学特征对成矿作用的指示[J].地球学报,2025,46(4):800-814,15.基金项目
本文由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 （编号:2024ZD1002203）
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)和湖北省地质局项目(编号:KJ2023-60 （编号:GPMR202427）
KCDZ2024-17)联合资助. This study was supported by Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project(No.2024ZD1002203),Hubei Natural Science Foundation(Nos.2025AFB351 and 2023AFD213),Special Funds of the Ministry of Science and Technology for the State Key Laboratory of Geological Processes and Mineral Resources(No.GPMR202427),and Hube Geological Bureau(Nos.KJ2023-60 and KCDZ2024-17). （No.2024ZD1002203）
