| 广西东平富Ga含锰岩系碳、氧同位素特征及意义 |
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| 引用本文： | 李启来,伊海生,夏国清,季长军,金峰.广西东平富Ga含锰岩系碳、氧同位素特征及意义[J].地球科学,2017,42(9):1508-1518. |
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| 作者姓名： | 李启来 伊海生 夏国清 季长军 金峰 |
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| 作者单位： | 1.成都理工大学沉积地质研究院, 四川成都 610059 |
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| 基金项目： | 国家科技支撑计划专题项目2011BAB04B10-2 |
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| 摘 要： | 在广西东平碳酸锰矿含锰岩系中发现Ga含量高异常，Ga含量为5.16×10-6~82.80×10-6，平均含量为33.76×10-6，达到了Ga矿资源工业品位标准要求，但目前还未见有产Ga锰矿床的报道.为了提升对此富Ga现象的认识，对其进行了碳、氧同位素特征研究.结果显示:矿石和围岩δ13CPDB值分别为-6.40‰~-2.20‰、-8.90‰~0.90‰，δ18OPDB值分别为-9.00‰~-7.90‰、-9.90‰~-3.90‰.研究表明:（1）有机质参与了碳酸锰矿形成；（2）含锰岩系为热水沉积成因，Ga来源与海底热液活动密切有关；（3）海底热液活动一方面为形成锰碳酸盐直接或间接提供了大量有机质，另一方面为形成富Ga含锰岩系带来了大量Ga，被锰的氧化物或氢氧化物、海洋生物（多为热液微生物）所吸附、富集，经复杂的成岩、成矿作用而最终赋存于含锰岩系之中形成富Ga含锰岩系.
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| 关 键 词： | 锰矿床 Ga异常 碳、氧同位素 矿床 |
| 收稿时间： | 2016-11-27 |
Characteristics and Implication of Carbon and Oxygen Isotopes in Ga-Rich Manganese-Bearing Rock Series in Dongping,Guangxi |
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| Abstract: | Recently, an unusually high content of Ga was discovered in manganese carbonate deposits of the Beisi Formation in Dongping area, Guangxi. The content of Ga is between 5.16×10-6 and 82.80×10-6, and the average content is 33.76×10-6, which reaches the industrial grade of Ga. But, to date Ga is not extracted from manganese deposits. In order to deepen the understanding of this phenomenon, the results of carbon and oxygen isotopes in the Ga-rich manganese-bearing rock series are reported in this paper. The results show that δ13CPDB of ores and host rocks are -6.40‰ to -2.20‰ and -8.90‰ to 0.90‰, respectively; δ18OPDB of ores and host rocks are -9.00‰ to -7.90‰ and -9.90‰ to -3.90‰, respectively. The results of the research show that (1) organic matter participates in the formation of manganese carbonate; (2) the Ga-rich manganese-bearing rock series belong to hydrothermal sedimentary genesis, and the source of Ga is related to seafloor hydrothermal activity; (3) seafloor hydrothermal activity plays a key role in the mineralization process of this Ga-rich manganese-bearing rock series, it directly or indirectly provides a large amount of organic matter to formation of manganese carbonates, on the other hand, it brought a lot of Ga that can be adsorbed by manganese oxides or hydroxide, marine organisms (mostly hydrothermal microorganism), then Ga concentrated in manganese-bearing rock series by complex diagenesis and mineralization. |
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