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| 粤北302铀矿床同位素地球化学研究 | |
| 引用本文： | 沈渭洲,凌洪飞,邓平,朱捌,黄国龙,谭正中.粤北302铀矿床同位素地球化学研究[J].铀矿地质,2010,26(2):80-87. |
| 作者姓名： | 沈渭洲 凌洪飞 邓平 朱捌 黄国龙 谭正中 |
| 作者单位： | 1. 南京大学地球科学与工程学院,内生金属矿床成矿机制研究国家重点实验室,江苏,南京,210093 2. 核工业290研究所,广东,韶关,512026;中国地质科学院地质研究所,北京,100037 3. 核工业290研究所,广东,韶关,512026 |
| 基金项目： | 核工业地质局科研项目，核工业地质局生产中科研项目，教育部科学研究重大项目 |
| 摘 要： | 位于粤北诸广山岩体东南部的302铀矿床是我国规模较大、埋藏较深的花岗岩型铀矿床之一。该矿床产于印支期油洞岩体和燕山早期长江岩体的断裂蚀变带内,矿区内NWW向基性岩脉十分发育,矿体呈似脉状、扁豆状或透镜状。同位素研究表明,矿石的沥青铀矿Sm-Nd和U-Pb等时线年龄（70 Ma）与油洞岩体（232 Ma）、长江岩体（160 Ma）的年龄相差巨大;主成矿期成矿流体的δDH2O值为-65‰～-82‰（平均为-75‰）,δ18OH2O值为6.8‰～0.6‰（平均为3.9‰）,反映出成矿流体主要由地幔流体组成;方解石的δ13C值为-8.4‰～-5.3‰,表明矿化剂ΣCO2也来自地幔;矿区内辉绿岩的（87Sr/86Sr）i值为0.70861～0.70882,花岗岩的（87Sr/86Sr）i值为0.73519～0.77152,萤石的（87Sr/86Sr）i值为0.71474～0.71697,表明成矿组分Sr可能来源于基性脉岩（幔源）与赋矿花岗岩体（壳源）,并呈不同程度的混合,而主成矿组分铀主要来源于赋矿花岗岩体。 |
| 关 键 词： | 同位素 地幔流体 成矿物质来源 粤北302铀矿床 |
Study on isotope geochemistry of uranium deposit 302 in northern Guangdong province |
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| SHEN Wei-zhou,LING Hong-fei,DENG Ping,ZHU Ba,HUANG Guo-long,TAN Zheng-zhong.Study on isotope geochemistry of uranium deposit 302 in northern Guangdong province[J].Uranium Geology,2010,26(2):80-87. | |
| Authors: | SHEN Wei-zhou LING Hong-fei DENG Ping ZHU Ba HUANG Guo-long TAN Zheng-zhong |
| Institution: | 1.State Key Laboratory for Mineral Deposit Research,School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210093,China;2.Research Institute No.290,CNNC,Shaoguan,Guangdong 512026,China;3.Geological Institute,Chinese Academy of Geological Science,Beijing 100037,China) |
| Abstract: | Located at the southeastern part of the Zhuguangshan granite composite in northern Guangdong province, uranium deposit 302 is one of the largest and most deeply buried granite-type uranium deposits in China. In the deposit area there are many NNW striking mafic dikes which intrude into the granite. The ore bodies appear in shape of vein-like, flat beanpod-like and lens-like within the hydrothermally altered fault zones in the Indosinian Youdong granite and early Yanshanian Changjiang granite. The formation age of the pitchblendes in ores (70 Ma) dated with Sm-Nd and U-Pb isochron methods is evidently different from that of the host Youdong granite (232 Ma) and Changjiang granite (160 Ma) dated with zircon U-Pb methods. Study of oxygen and hydrogen isotopes at main metallogenic epoch reveals that the δD_(H_2O) value of ore-forming fluid ranges from -65‰ to -82‰ with the average value of -75‰ and δ~(18)O_(H_2O) ranges from 6.8‰ to 0.6‰ with the average of 3.9‰ which indicate that the ore-forming fluids were mainly composed of mantle-derived fluids. Calcites in the ore veins have δ~(13)C values between -8.4‰ and -5.4‰ which indicate that the ΣCO_2 were also originated from the mantle, while the diabase dikes and granites in the deposit area have initial (~(87)Sr/~(86)Sr)i ratios of 0.70861-0.70882 and 0.73519-0.77152 respectively and the fluorites have initial (~(87)Sr/~(86)Sr)i ratios of 0.71474-0.71697 which implicate that the Sr in the ore-forming fluids may have been a mixture of Sr from mafic dikes and granites. The uranium of the deposit may have been from the granites. |
| Keywords: | isotopes mantle fluids sources of ore-forming materials uranium deposit 302 |
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