Characteristics of rare-earth elements (REE), strontium and neodymium isotopes in hydrothermal fluorites from the Bailashui tin deposit in the Furong ore field, southern Hunan Province, China
Characteristics of rare-earth elements (REE), strontium and neodymium isotopes in hydrothermal fluorites from the Bailashui tin deposit in the Furong ore field, southern Hunan Province, China
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DOI：
10.1007/s11631-008-0342-5
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发表时间：
2008-11
期刊：
影响因子：
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通讯作者：
Shunda Yuan;Jian‐tang Peng;R. Hu;X. Bi;L. Qi;Zhao-li Li;Xiaomin Li;Shuang Yan
中科院分区：
文献类型：
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作者：
Shunda Yuan;Jian‐tang Peng;R. Hu;X. Bi;L. Qi;Zhao-li Li;Xiaomin Li;Shuang Yan
本文报道了湘南芙蓉矿白拉水锡矿床萤石的稀土元素浓度和Sr、Nd同位素组成。结果表明：萤石中稀土元素总量一般较低，介于0.705 ~ 8.785 μg/g之间，其球粒陨石归一化稀土元素分布模式与齐天岭花岗岩相似，呈低稀土元素富集模式，Eu负异常明显；萤石Sr同位素组成变化范围为0.7083 ~ 0.7091，低于花岗岩，高于寄主碳酸盐岩。萤石的Nd(t)值在−9.4 ~ +10.3之间变化，表明成矿热液中既有地壳源物质，也有地幔源物质。结合前人对该矿床的研究，认为白拉水锡矿床在时间和空间上与本区花岗质岩浆活动密切相关。热液萤石是花岗质岩浆热液与海相碳酸盐岩流体/岩石相互作用的产物。成矿流体中的REE和F主要来源于花岗岩，而Sr主要来源于花岗岩岩浆热液和海相碳酸盐岩，但Sr同位素组成的变化不能简单地用这两个端元的混合来解释。有证据表明，成矿流体为地壳-地幔混合流体，但流体可能不完全均匀化，这可能是由于不同来源的流体混合不均匀所致。
In this paper the authors present the REE concentrations and Sr and Nd isotopic compositions of fluorites from the Bailashui tin deposit of the Furong ore field, southern Hunan Province. The results showed that the total amount of REE in fluorites is usually low, ranging from 0.705 to 8.785 μg/g with the chondrite-normalized REE distribution patterns similar to those of the Qitianling granites in the study area, characterized by LREE-enrichment patterns with pronounced negative Eu anomalies. The fluorites vary in Sr isotopic composition within the range of 0.7083–0.7091, the values are lower than those of the granites and higher than those of the host carbonate rocks in this area. The ɛNd(t) values of fluorites vary between −9.4 and +10.3, revealing that both the crust-and mantle-source materials were involved in the ore-forming hydrothermal fluids. Combined with previous studies on this ore deposit, the Bailashui tin deposit is temporally and spatially closely related with granitic magmatism in this area. The hydrothermal fluorites are the product of fluid/rock interactions between granitic magmatic hydrothermal fluid and marine carbonate rocks. The REE and F in the ore-forming fluid were derived from the granites, whereas Sr in the ore-forming fluid came mainly from the granitic magmatic hydrothermal fluid and marine carbonate rocks, although variations in Sr isotopic composition cannot be explained by a simple mixture of these two end-members. Evidence demonstrated that the ore-forming fluids are of crustal-mantle mixing origin, but that the fluids were probably incompletely homogenized and this may be caused by inhomogeneous mixing of the fluids of different sources.