| 江西相山铀矿田河元背地区流纹斑岩地球化学、锆石U Pb年龄及Hf Sr Nd同位素特征 |
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| 引用本文： | 司志发,李子颖,聂江涛,刘军港,王健,田明明.江西相山铀矿田河元背地区流纹斑岩地球化学、锆石U Pb年龄及Hf Sr Nd同位素特征[J].现代地质,2018,32(1):45. |
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| 作者姓名： | 司志发 李子颖 聂江涛 刘军港 王健 田明明 |
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| 作者单位： | 1核工业北京地质研究院，北京100029；2中核铀资源勘查与评价技术重点实验室，北京100029 |
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| 基金项目： | 中核集团科技创新示范工程项目（LCD116）。 |
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| 摘 要： | 在江西相山铀矿田河元背地区实施的CUSD3钻孔，发现其深部存在晚期侵入到打鼓顶组流纹英安岩、凝灰岩、泥质粉砂岩中的流纹斑岩。利用激光等离子质谱分析技术(LA ICP MS)测得流纹斑岩的锆石206Pb/238U年龄为(1318±07)Ma (MSWD=041)，晚于前人所测的鹅湖岭组碎斑流纹岩年龄。该流纹斑岩具有高硅、富钾、铝过饱和等特点，还表现出高场强元素Rb、Th、U、La、Ce、Nd和LREE富集，Ba、Nb、Sr、P、Ti等元素亏损以及δEu明显负异常的特点。锆石的εHf(t)值介于 -677~-1038之间，对应的二阶段Hf模式年龄TDMC介于1 619~1 846 Ma，岩石的ISr值为0710 92~0712 01，εNd(t)值为-818~-919。其稀土元素、微量元素分布模式及同位素特征与前人报道的碎斑流纹岩特征类似，暗示流纹斑岩与碎斑流纹岩具有相同的物质来源。以上特征说明河元背地区流纹斑岩形成于早白垩世造山运动碰撞后伸展阶段，为深部硅铝质地壳部分熔融的产物。相山西部流纹斑岩的发现，可以推测该区或许存在一个次级火山机构。
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| 关 键 词： | 流纹斑岩 地球化学 锆石U Pb年龄 Hf Sr Nd同位素 相山铀矿田 |
Geochemistry,Zircon U-Pb Geochronology and Hf-Sr-Nd Isotopic Characteristics of the Rhyolite Porphyry at Heyuanbei in Xiangshan Uranium Ore-field,Jiangxi Province |
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| SI Zhifa,LI Ziying,NIE Jiangtao,LIU Jungang,WANG Jian,TIAN Mingming.Geochemistry,Zircon U-Pb Geochronology and Hf-Sr-Nd Isotopic Characteristics of the Rhyolite Porphyry at Heyuanbei in Xiangshan Uranium Ore-field,Jiangxi Province[J].Geoscience——Journal of Graduate School,China University of Geosciences,2018,32(1):45. |
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| Authors: | SI Zhifa LI Ziying NIE Jiangtao LIU Jungang WANG Jian TIAN Mingming |
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| Institution: | (1Beijing Research Institute of Uranium Geology, CNNC, Beijing100029,China;
2 Key Laboratory of Uranium Resource Exploration and Evaluation Technology, CNNC, Beijing100029,China) |
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| Abstract: | A suite of rhyolite porphyry was found at Heyuanbei in Xiangshan uranium ore field of Jiangxi Province, which intruded into the rhyodacite, tuff, argillaceous siltstone. LA ICP MS U Pb isotopic dating on zircons from the rhyolite porphyry yields magmatic crystallization age of (1318±07) Ma (MSWD=041). The rhyolite porphyry is characterized by high in SiO2, K2O, Al2O3 and relatively low in MnO and P2O5. It is enriched in Rb, Th, U, La, Ce, Nd and light rare earth elements, depleted in Ba, Nb, Sr, P and Ti, and shown slightly negative Eu anomalies (δEu=021-025). The zircon εHf(t) values range from -677 to -1038, with Hf depleted mantle model ages (TDMC) between 1 619 and 1 846 Ma. The ISr values range from 0710 92 to 0712 01. And the εNd(t) values range from -818 to -919. The experimental results indicate that the rock was generated by partial melting of crustal rocks during extension in Lower Cretaceous. And a sub volcanic conduit may exist in the west of Xiangshan. |
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| Keywords: | rhyolite porphyry geochemistry zircon U Pb dating Hf Sr Nd isotope Xiangshan uranium ore field |
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