摘要
湖南邓阜仙矿田是我国华南著名的钨锡多金属矿产地,随着多年的矿山开采,资源已逐渐枯竭,亟需新的找矿突破。近期在矿田西侧发现多处隐爆角砾岩,为钨锡成矿作用和找矿勘查打开了新窗口。本文对该隐爆角砾岩开展了系统地质调查、岩相学、岩石地球化学、锆石年代学与Lu-Hf同位素分析,研究表明:1)隐爆角砾岩筒主要沿茶陵-郴州-临武断裂发育,具有显著分带性,从中心到外围依次为长英质岩脉、隐爆角砾岩带、裂隙带,且存在多期热液活动与矿化;2)长英质岩脉锆石U-Pb加权年龄为(151.9±1.2)Ma,形成时代与矿田成矿高峰期一致;3)岩脉富集Rb、Th和U,亏损Sr、Ba、K和P等元素,具有高的分异指数(DI为94.77~97.11),其锆石ε_(Hf)(t)为-6.8~-0.8(均值为-4.7),TDM2为1253~1638 Ma,与矿田成矿花岗岩具有相似的微量元素和Lu-Hf同位素组成,指示二者应为同一岩浆源区。综合分析认为,矿田隐爆角砾岩与钨锡多金属成矿关系密切,尽管目前已发现的钨锡矿床均集中在矿田东部,但是西部同样有较大的钨锡找矿潜力,尤其是茶陵-郴州-临武断裂附近。隐爆角砾岩是寻找钨锡多金属矿床的有利找矿标志,应给予高度重视。
Dengfuxian ore field in Hunan is a famous tungsten-tin polymetallic ore field in South China.With years of mining,the resources have been gradually exhausted,and there is an urgent need for new prospecting breakthroughs.Recently,many cryptoexplosive breccias have been discovered on the west side of the ore field,opening a new window for W-Sn mineralization prospecting.In this study,systematic geological survey,petrography,rock geochemistry,zircon chronology and Lu-Hf isotope analysis have been carried out.The results show that:1)Cryptoexplosive breccia pipes are mainly developed along the Chaling-Chenzhou-Linwu fault,with a significant zoning characteristic.From the center to the periphery,it changes from felsic dykes to cryptoexplosive breccia belts and then to fissure belts,and there are multiple periods of hydrothermal activity and mineralization;2)The U-Pb weighted age of zircon in felsic dykes is(151.9±1.2)Ma,which is consistent with the metallogenic peak of the ore field;3)The dykes are enriched in Rb,Th and U,depleted in some trace elements such as Sr,Ba,K and P,with high differentiation index(DI=94.77−97.11),zircon ɛ_(Hf)(t)=−6.8-−0.8(mean=−4.7),T DM2=1253−1638 Ma,and have similar trace elements and Lu-Hf isotopes to the ore-forming granites in composition,indicating that they have the same magma source region.The comprehensive analysis shows that the cryptoexplosive breccias in the ore field are closely related to W-Sn polymetallic mineralization.Although the W-Sn deposits that have been discovered so far are concentrated in the eastern part of the ore field,there is also a great potential for W-Sn ore prospecting in the west,especially near the Chaling-Chenzhou-Linwu fault.The cryptoexplosive breccia is a favorable prospecting sign for W-Sn polymetallic deposits,which should be given great attention.
作者
康凡
李欢
刘飚
吴堑虹
孔华
奚小双
谭富诚
KANG Fan;LI Huan;LIU Biao;WU Qian-hong;KONG Hua;XI Xiao-shuang;TAN Fu-cheng(Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Hunan Changsha 410083,China;School of Geosciences and Info-Physics,Central South University,Hunan Changsha 410083,China)
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2023年第3期931-951,共21页
The Chinese Journal of Nonferrous Metals
基金
湖南省自然科学青年基金资助项目(2021JJ40722)
国家重点研发计划资助项目(2018YFC0603902)。
