Geochrology, Geochemistry and Petrogenesis of Ore-Related Granite in the Dongping Tungsten Deposit in Wuning County, Jiangxi~Province
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摘要: 江西省东坪钨矿床位于江南造山带东段,是中国新发现的超大型“五层楼式”石英脉型黑钨矿矿床.为探讨东坪钨矿床的成矿岩浆岩形成时代、来源及其构造背景,在详实的野外地质调查基础上对东坪成矿黑云母花岗岩进行了详细的锆石U-Pb年代学、主量、微量元素地球化学以及Sr-Nd同位素研究.LA-ICP-MS锆石U-Pb定年测得东坪黑云母花岗岩结晶年龄为132.9~1.4 Ma} (MSWD=0.40,{\it n}=25);岩石地球化学特征表明黑云母花岗岩为高硅高钾钙碱性过铝质高分异S型花岗岩,u(SiO2)为73.19%~75.21%、(Na2O+K2O)为6.84%~8.45%、A/CNK为1.21~1.44,亏损Sr、Ba、Ti,富集Rb、Th、U、P;REE为43.52~60.88 ug/g,轻稀土富集,重稀土亏损,强负铕异常(Eu/Eu*=0.21$\sim$0.41),稀土配分曲线呈右倾深“V”型.黑云母花岗岩(87Sr/86Sr)i值介于0.715 1~0.725 8,Nd( t)值介于-3.28~-5.99,两阶段模式年龄 TDM2为1.57~1.84 Ga( t=132.9 Ma).综合分析认为,东坪成矿岩浆岩来源于富泥质岩石熔融,其源区岩石很可能是华南中元代古老基底物质的再循环,形成于太平洋板块俯冲引起的陆内“伸展-拉张”动力学背景.Abstract: The Dongping tungsten deposit,located in the eastern section of Jiangnan orogenic belt in Jiangxi Province, which is a newly discovered giant “five-story” quartz vein type wolframite ore deposit. In order to study the metallogenic magmatic rock of the age, source and tectonic background of the Dongping tungsten deposit, this paper has carried out detailed zircon U-Pb chronology, major-trace element geochemistry,and Sr-Nd isotope studies of the Dongping metallogenic biotite granite. LA-ICP-MS zircon U-Pb dating results demonstrate the age of Dongping biotite granite is 132.9~1.4 Ma...
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Key words:
- zircon U-Pb dating /
- geochemistry /
- biotite granite /
- Tungsten deposit /
- Dongping /
- North Jiangxi~Province
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