| 粤北石土岭铀矿床同位素地球化学研究 |
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| 引用本文：.2006.Isotopic geochemistry of Shituling uranium deposit, northern Guangdong Province, China[J].Mineral Deposits,25(1):71~82 |
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| 基金项目:国家自然科学基金重点项目（40132010）、高等学校博士学科点专项基金（200402 84039）和创新群体项目（40221301） |
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| 中文摘要:石土岭铀矿床位于贵东岩体东南部与寒武纪浅变质岩接触带的内带，矿区内NWW向和NNE向基性岩脉十分发育。矿体主要赋存于帽峰岩体中，呈脉状产出，并受近EW向裂隙构造控制。沥青铀矿的U_Pb年龄（135 Ma）与帽峰岩体的年龄（220 Ma）相差明显，但与NWW向辉绿岩脉的年龄（143 Ma）十分接近。矿石中黄铁矿的初始87Sr/86Sr值（0.71315～0.72579）介于成矿期间辉绿岩的值（0.70449～0.70632）与帽峰和下庄岩体演化至成矿时期(135 Ma)的值（0.75058～0.99507）之间；黄铁矿的铅同位素组成呈线性分布，为基底变质岩铅与帽峰岩体铅及辉绿岩铅之间不同程度的混合。Sr、Pb同位素组成显示出成矿组分具多来源特征；成矿流体的δ18OH2O=2.0‰～8.1‰，δDH2O=-63‰～-51‰，反映出成矿流体主要由幔源流体组成；方解石的δ13C=-8.3‰, 表明矿化剂∑CO2也来自地幔。因此，幔源流体在石土岭铀矿床的形成中具有十分重要的意义。 |
| 中文关键词:地球化学 同位素 幔源流体 成矿物质来源 石土岭铀矿床 粤北 |
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| Isotopic geochemistry of Shituling uranium deposit, northern Guangdong Province, China |
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| Abstract:The Shituling uranium deposit is located on the granitic side of the contact zon e between the southeastern part of Guidong granite and the Precambrian low_grade metamorphic rocks. There occur many NWW_ and NNE_striking basic veins in this a rea. The veinlike ore bodies mainly hosted in Maofeng granite are controlled by EW_trending fissure structures. The U_Pb age of uraninite (135 Ma) is obviously different from the formation age of Maofeng granite but close to the age of NWW_ trending diabase veins. The initial 87Sr/86Sr values of pyrite ( 0.71315～0.72579) in the ore are between those of NWW_striking diabase（0.70449 ～0.70632）and Maofeng and Xiazhuang granites (0.75058～0.99507) at 135 Ma. The linear Pb isotope distribution of pyrite from the ore indicates that Pb in the ore was a m ixture of Pb derived from the basement metamorphic rock, Maofeng granite and dia base. The Sr and Pb isotopes show multiple_source characteristics of the ore_for ming components. The ore-forming fluids have δ18OH2O of 2.0‰～8. 1‰ and δDH2O of -63‰～-51‰, suggesting that the ore_forming fluids w ere mainly composed of mantle fluids. The calcite δ13C of -8.3‰ suggests that the ∑CO2 in the fluids came from the mantle. Therefore, the mantle flui ds might have played an important role in uranium mineralization of the Shitulin g uranium deposit. |
| keywords:geochemistry, isotope, mantle fluids, source of ore_forming components, Shituling uranium deposit northern Guangdong Province |
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