Geochemical Characteristics and Their Causative Mechanism of Polymetallic Nodules from the Northwest Continental Margin of the South China Sea
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摘要: 对取自南海西北陆缘海域的大型多金属结核进行了电子探针、X射线粉晶衍射(XRD)、等离子质谱仪(ICP-MS) 和等离子光谱仪(ICP-AES) 等方面的分析.结核核心部位的主要矿物组成为石英、伊利石、钠长石和绿泥石, 壳层的主要矿物为δMnO2等.铁、锰组分呈现Fe含量高、Mn含量低和Mn/Fe低的特征.Si含量高, Cu、Co、Ni含量低; 稀土元素(REE) 含量高, 平均为1472.30×10-6, 轻稀土与重稀土的比值(LREE/HREE) 达19.54, 并且存在较强的Ce正异常.元素含量的变化显示: 从结核内壳层到外壳层, Fe、Mn、Cu、Co等元素含量呈不规律变化, 具有典型的边缘海特征, 该特征反映结核在形成过程中受到边缘海沉积环境波动变化的影响, 陆源物质供应量的增加对Fe、REE、Si等元素的富集起到了促进作用, 而对Mn、Ca等元素的富集则产生明显的稀释作用.多金属结核Mn/Fe比及Mn-Fe- (Cu+Ni) ×10三组分图解显示, 南海北部陆缘多金属结核为水成成因, 该成因与结核所赋存的边缘海环境密切相关, 反映了结核成长发育的过程中, 南海典型的边缘海沉积条件和多变的古海洋环境因素对其产生了重要影响.Abstract: This study employs various observation and analytical techniques including electron microprobe analysis, X-ray difraction (XRD) and ICP-MS (AES) on polymetallic nodules collected from the northwest continental margin of the South China Sea. The analyses indicate that the cores of the samples are made up of quartz, illite, albite and chlorite, whereas the shells are made up of δMnO2. The samples are rich in Fe, Si, and ∑REE, and they are poor in Mn, Cu, Co and Ni. These samples show lower ratios of Mn/Fe. The characteristics of the REE (rare earth elements) show higher contents with more than 1472.30×10-6 in average. Heavy REE (HREE) depletes relative to the light REE (LREE) very obviously that the latter is 19.54 times than that of the former, and shows distinct enrichment of δCe. The elements of Fe, Mn, Cu and Co change obviously in different ways from the inner crust to the outer. These characteristics show that the growth of the nodules has been affected by the environmental fluctuations and the change of terrigenous sediments. In this condition, Fe, REE and Si are enrichment, but Mn and Ca are dilutedness. Elements correlation of Mn-Fe- (Cu+Ni) ×10 suggests that the origin of the sample may be hydrogenic. This study comes to the conclusion that these nodules are dominative due to the special environment of the marginal sea which includes the geographical condition and the oceanic environmental factors.
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图 1 样品的外部形态及内部结构
Fig. 1. Morphological features and inner structures of the polymetallic nodules
图 2 南海多金属结核X射线衍射
δ.水羟锰矿; Q.石英; M.云母; An.长石; C.绿泥石
Fig. 2. X-ray diffraction analysis results of the polymetallic nodules
图 3 南海多金属结核样品北美页岩标准化配分曲线
Fig. 3. REE distribution pattern for normalized shale of the polymetallic nodules
表 1 南海多金属结核矿物组成及其组分含量
Table 1. Minerals and major components of the polymetallic nodules
表 2 南海多金属结核主要组分含量(%)
Table 2. Major components of the polymetallic nodules
表 3 南海多金属结核样品稀土元素含量(10-6)
Table 3. REE contents of the polymetallic nodules
表 4 南海多金属结核微量元素含量(10-6)
Table 4. Trace elements of the polymetallic nodules
表 5 南海北部陆缘多金属结核部分元素相关系数矩阵
Table 5. Some elements relationship of the polymetallic nodules
表 6 南海多金属结核与大洋结核的主要组分含量比较(%)
Table 6. Comparison of main elements between the different samples
表 7 南海多金属结核与大洋结核几种微量元素含量比较(10-6)
Table 7. Comparison of trace elements between the different samples
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[1] Bao, G. D., Li, Q. X., 1993. Geochemistry of rare earth elements in ferromanganese nodules (crusts) of the South China Sea. Oceanologia et Limnologia Sinica, 24 (3): 304-313 (in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTotal-HYFZ199303011.htm [2] Chen, Y. W., Gui, X. T., 1998. Isotope geochemistry of theNansha Islands sea area. Science Press, Beijing, 65-129 (in Chinese). [3] Feng, X. H., Tan, W. F., Liu, F., et al., 2008. Hydrothermal synthesis of todorokite and its influencing factors. Earth Science—Journal of China University of Geosciences, 30 (3): 347-352 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQKX200503011.htm [4] Florence, N., Peter, J., Matt, M., 2007. Processes influencing dissolvediron distributions below the surface at the Atlantic Ocean-celtic sea shelf edge. Marine Chemistry, 104 (3-4): 156-170. doi: 10.1016/j.marchem.2006.10.011 [5] Kennett, J. P., Watkins, N. D., 1975. Deep sea erosion and manganese nodule development in Southeast Indian Ocean. Science, 188: 1011-1013. doi: 10.1126/science.188.4192.1011 [6] Lei, G., Bostrom, K., 1995. Mineralogical control on transition metal distributions in marine manganese nodules. Marine Geology, 123 (3-4): 253-261. doi: 10.1016/0025-3227(95)00022-Q [7] Li, S. L., 2001. Geochemistry of rare earth element in sediments at HY126EA1hole in the continental shelf of the East China Sea. Acta Oceanologica Sinica, 23 (3): 127-132 (in Chinese with English abstract). http://d.wanfangdata.com.cn/Periodical/hyxb200103016 [8] Lin, Z. H., Ji, F. W., Zhang, F. Y., et al., 2003. Characteristics and origin of ferromanganese nodules from the northeastern continental slope of the South China Sea. Marine Geology & Quaternary Geology, 23 (1): 7-12 (in Chinese with English abstract). http://d.wanfangdata.com.cn/periodical/hydzydsjdz200301002 [9] Philomène, A. V., David, S. C., Charles, L. M., 2004. Acomparative analysis of compositional variations in and between marine ferromanganese nodules and crusts in the South Pacific and their environmental controls. Progress in Oceanography, 63 (3): 125-158. doi: 10.1016/j.pocean.2004.11.001 [10] Shi, Y. Z., Hu, C. Y., Fang, N. Q., et al., 2004. Carbon-isotopic composition of organic matter in Co-rich ferromanganese crusts and its implication for paleoceanography. Earth Science—Journal of China University of Geosciences, 29 (2): 148-150, 156 (in Chinese with English abstract). http://www.researchgate.net/publication/291105585_Carbon_isotopic_composition_of_organic_matter_in_co-rich_ferromanganese_crust_and_its_implication_for_paleoceanography [11] South China Sea Institute of Oceanology, Chinese Academy of Sciences. 1985. Integrated surveying report of the South China Sea (Ⅱ). Science Press, Beijing, 98-101 (in Chinese). [12] Wang, X. J., Chen, Y. W., Wu, M. Q., 1984. Geochemistry of RE and trace elements in ferromanganese nodules and their genesis. Oceanologia et Limnologia Sinica, 15 (6): 501-514 (in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTotal-HYFZ198406000.htm [13] Xu, D. Y., Jin, Q. H., Liang, D. H., 1994. The ferromanganese nodules (crusts) and their genesis environment. Geological Publishing House, Beijing, 95-105 (in Chinese). [14] Xu, Z. K., Li, A. C., Jiang, F. Q., et al., 2006. Paleoenvironments recorded in a new-type ferromanganese crust from the east philippine sea. Earth Science—Journal of China University of Geosciences, 31 (3): 301-308 (inChinese with English abstract). http://www.sciencedirect.com/science/article/pii/S1002070506600046 [15] Xu, Z. K., Li, A. C., Yu, X. K., et al., 2008. Elemental occurrence phases of the new-type ferromanganese crusts from the east philippine sea. Earth Science—Journal of China University of Geosciences, 33 (3): 329-336 (inChinese with English abstract). doi: 10.3799/dqkx.2008.043 [16] Zhang, Z. G., 2007. Approach to geochemical characteristicsand minerogenetic environment of polymetallic nodulesfrom the northern continental margin of the SouthChina Sea (Dissertation). China University of Geosciences, Beijing (in Chinese). [17] Zhang, Z. G., Fang, N. Q., Du, Y. S., et al., 2008. Comparison between northwestern continental margin of the South China Sea and other oceans of geochemical characteristics of polymetallic nodules. Marine Geology & Quaternary Geology, 28 (4): 55-60 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-HYDZ200804008.htm [18] Zhu, K. C., Li, Z. S., He, G. W., et al., 2001. The mineral resources of polymetallic nodules in the eastern Pacific Ocean. Geological Publishing House, Beijing, 163-172 (in Chinese). [19] 鲍根德, 李全兴, 1993. 南海铁锰结核(壳) 的稀土元素地球化学. 海洋与湖沼, 24 (3): 304-313. doi: 10.3321/j.issn:0029-814X.1993.03.013 [20] 陈毓蔚, 桂训堂, 1998. 南沙群岛海区同位素地球化学研究北京: 科学出版社, 65-129. [21] 冯雄汉, 谭文峰, 刘凡, 等, 2005. 热液条件下钙锰矿的合成及其影响因素. 地球科学———中国地质大学学报, 30 (3) 3: 47-352. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200503011.htm [22] 李双林, 2001. 东海陆架HY126EA1孔沉积物稀土元素地球化学. 海洋学报, 23 (3): 127-132. doi: 10.3321/j.issn:0253-4193.2001.03.016 [23] 林振宏, 季福武, 张富元, 等, 2003. 南海东北陆坡区铁锰结核的特征和成因. 海洋地质与第四纪地质, 23 (1): 7-12. https://www.cnki.com.cn/Article/CJFDTOTAL-HYDZ200301002.htm [24] 史跃中, 胡超涌, 方念乔, 等, 2004. 富钴结壳中有机碳同位素组成特征及其古海洋意义. 地球科学———中国地质大学学报, 29 (2): 148-150, 156. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200402004.htm [25] 王贤觉, 陈毓蔚, 吴明清, 1984. 铁锰结核的稀土和微量元素地球化学及其成因. 海洋与湖沼, 15 (6): 501-514. https://www.cnki.com.cn/Article/CJFDTOTAL-HYFZ198406000.htm [26] 许东禹, 金庆焕, 梁德华, 1994. 太平洋中部多金属结核及其形成环境. 北京: 地质出版社, 95-105. [27] 徐兆凯, 李安春, 蒋富清, 等, 2006. 东菲律宾海新型富铁锰结壳的古海洋环境记录. 地球科学———中国地质大学学报, 31 (3): 301-308. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200603002.htm [28] 徐兆凯, 李安春, 于心科, 等, 2008. 东菲律宾海新型铁锰结壳中元素的赋存状态. 地球科学———中国地质大学学报, 33 (3): 329-336. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200803006.htm [29] 张振国, 2007. 南海北部陆缘多金属结核地球化学特征及成矿意义(博士学位论文). 北京: 中国地质大学. [30] 张振国, 方念乔, 杜远生, 等, 2008. 南海西北陆缘多金属结核地球化学及其与大洋结核的对比. 海洋地质与第四纪地质, 28 (4): 55-60. https://www.cnki.com.cn/Article/CJFDTOTAL-HYDZ200804008.htm [31] 中国科学院南海海洋研究所, 1985. 南海海区综合调查报告(二). 北京: 科学出版社, 98-101. [32] 朱克超, 李振韶, 何高文, 等, 2001. 东太平洋多金属结核矿产. 北京: 地质出版社, 163-172. -
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