豫西卢氏五里川地区柳树湾铀矿碱交代成矿作用  

Influence of Alkali Metasomatic Mineralization on Liushuwan Uranium Deposit in Lushi Wulichuan Area,West Henan Province

作　　者：冯晓曦 滕雪明 耿建珍[1,2,3] Feng Xiaoxi;Teng Xueming;Geng Jianzhen(Tianjin Center of China Geological Survey,Tianjin 300170,China;North China Center of Geoscience Innovation,Tianjin 300170,China;Key Laboratory of Uranium Geology,China Geological Survey,Tianjin 300170,China)

机构地区：[1]中国地质调查局天津地质调查中心,天津300170 [2]华北地质科技创新中心,天津300170 [3]中国地质调查局铀矿地质重点实验室,天津300170

出　　处：《地球科学》2024年第4期1189-1206,共18页Earth Science

基　　金：中国地质调查局地质调查项目(No.DD20221686).

摘　　要：豫西卢氏五里川地区新发现的柳树湾铀矿碱交代成矿作用明显,对于豫西成矿带新一轮找矿战略行动具有直接指示意义.通过岩石学、岩石化学和同位素定年等研究,认为早古生代中期,深源岩浆上侵、熔融、交代中元古代秦岭微陆块,形成富碱含铀的灰池子岩体(429.4±5.3 Ma)和花岗伟晶岩(417.4±2.3 Ma);早古生代晚期,混有幔源成分的含U、Na、Zr、Hf流体和含U、K、Nb、Ta流体富碱流体交代花岗伟晶岩,塑造了柳树湾花岗伟晶岩铀矿床;富碱流体在改变了岩体及伟晶岩的碱质(K+Na)、硅质(SiO_(2))、REE和Zr、Hf、Ti等元素分布环境的过程中,导致锆石U-Pb、白云母Ar-Ar和辉钼矿Re-Os同位素封闭体系受损.碱交代作用是岩体、花岗伟晶岩成岩以及柳树湾铀成矿的根本原因.In order to discuss the mineralization of the Liushuwan uranium deposit in the Lushi Wulichuan area,West Henan Province,whose distinct alkali metasomatic mineralization has direct directive significance for a new round of prospecting strategic action in West Henan metallogenic belt.Therefore,it tests Huichizi pluton and exteral granitic pegmatite by petrology,petrochemistry,isotope zircon,muscovite,molybdenite incasing the granitic pegmatite by LA-ICP-MS U-Pb,Ar-Ar and Re-Os to find their linkage to uranium mineralization.It is recognized that the alkali metasomatism of mantle-derived fluids records the uranium mineralization.In Early Paleozoic,mantle derived alkaline magma invaded,melted and metasomatized the Mesoproterozoic Qinling microblocks to produce the uranium-bearing I-type Huichizi pluton(429.4±5.3 Ma)and granitic pegmatite(418.7±2 Ma),which accumulates uranium sources and served as a carrier for uranium ore.Post the formation of the granitic pegmatitte,fluid derived mantle continuously intruded and alkali metasomatised the Qingling Group,the Huichizi pluton and the pegmatite,which could alter their contents including K+Na,SiO_(2),REE,Zr,Hf,Ti,etc.In that case,the U-Pb,Ar-Ar and Re-Os isotopic closed systems respectively for zircon,muscovite and molybdenite would be broken.Two types of uranium-bearing hydrothermal fluids,respectively Na-Zr-Hf rich and K-Nb-Ta rich,mantle derived magma successively metasomatized the peripheral pegmatite of the Huichizi pluton to contribute the final formed Liushuwan granitic pegmatite uranium deposit.In summary,the mantle derived magma induced alkali metasomatism is the fundamental factor to contribute the spatial allocation of the Liushuwan uranium deposit,the Huichizi pluton and the granitic pegmatite.The uranium-bearing hydrothermal solution derivated from the mantle-sourced magma is the direct factor to the uranium mineralization.The alkali metasomatism destroyed the geochemical signature and isotopic system of the Huichizi pluton and the granitic pegmatite.Uranium

关 键 词：豫西卢氏 柳树湾铀矿 岩石化学 同位素测年 碱交代作用 矿床学 

分 类 号：P611.1[天文地球—矿床学]