杨娅敏^1,2, 曾志刚^1,3,2,4, 殷学博^1,3,4, 荣坤波¹, 舒云超⁵
1.中国科学院海洋研究所 海洋地质与环境重点实验室, 山东 青岛 266071;2.中国科学院大学, 北京 100049;3.青岛海洋科学与技术试点国家实验室 海洋矿产资源评价与探测技术功能实验室, 山东 青岛 266061;4.中国科学院 海洋大科学研究中心, 山东 青岛 266071;5.Department of Geology and Geophysics, Woods HoleOceanographic Institution, Woods Hole, MA 02543, USA

摘要:
综合前人发表的关于太平洋、大西洋以及印度洋等深海沉积物中稀土元素含量的数据，本文较为系统地阐述了全球深海富REY泥（REY-rich mud）的分布，分析了不同沉积环境下富REY泥中稀土元素的赋存载体及其控制因素，并进一步探讨了赋存载体中稀土元素的富集机制。研究发现深海富REY泥主要分布在太平洋和印度洋的深海盆地中，其中西北太平洋南鸟岛附近海域沉积物中稀土元素最为富集，是较为有利的稀土资源勘探潜力区。邻近热液区，深海沉积物中稀土元素含量受热液活动影响较大，稀土元素的主要赋存相是Fe-Mn水合（氢）氧化物，可能是热液流体扩散过程中，颗粒物中的Fe-Mn水合（氢）氧化物等吸附（scavenge）海水中的稀土元素所致。而在远离热液区的正常深海富REY泥中，高磷含量以及低沉积速率是导致其稀土含量相对较高的主要因素，赋存载体主要是生物成因磷灰石（鱼牙骨碎屑）。在磷灰石早期成岩阶段，海水和孔隙水中的REY进入磷灰石，在羟基磷灰石晶格中REE³⁺与磷灰石中的Ca²⁺发生类质同象替代：REE³⁺+Na⁺↔2Ca²⁺和REE³⁺+Si⁴⁺↔Ca²⁺+P⁵⁺，使其不断地富集稀土元素，但这还需要进一步研究。
关键词:稀土元素赋存载体富集机制深海富REY泥
DOI：10.11759/hykx20181129002
分类号:736.4
基金项目:国家全球变化与海气相互作用专项（GASI-GEOGE-02）；中国科学院国际合作局对外合作项目（133137KYSB20170003）；泰山****工程专项（ts201511061）；中国大洋协会“十三五”国家专项基金（DY135-G2-01-02）；国家重点基础研究计划（2013CB429700）；国家自然科学基金中国基金会（41325021）；青岛海洋科学与技术国家实验室鳌山科技创新计划项目（2015ASKJ03，2016ASKJ13）

Advances in research on the host and the enrichment mechanism of REY-rich mud in deep-sea Sediments
YANG Ya-min^1,2, ZENG Zhi-gang^1,3,2,4, YIN Xue-bo^1,3,4, RONG Kun-bo¹, SHU Yun-chao⁵
1.Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;2.University of Chinese Academy of Sciences, Beijing 100049, China;3.Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China;4.Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China;5.Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
Abstract:
Based on the previously published data on the content of rare-earth elements in deep-sea sediments such as those in the Pacific, Atlantic, and Indian Oceans, the distribution of the REY-rich mud is elaborated in this paper. Furthermore, the hosts and the controlling factors of rare-earth elements in the REY-rich mud in different sedimentary environments are analyzed, and the enrichment mechanisms of the hosts are discussed. The REY-rich mud was found to be mainly distributed in the deep basins of the Pacific and the Indian Oceans, and the REY was extremely enriched around Minamitorishima Island, which can be regarded as a potential mineral resource for rare-earth elements. Near hydrothermal activity areas, the concentration of REY was largely controlled by the hydrothermal activity. The data also indicated that one of the main hosts for the REY was Fe-Mn oxyhydroxides precipitated from hydrothermal plume, which can scavenge the rare earth elements from ambient seawater in the process of hydrothermal fluid diffusion. Away from the vents, the high phosphorus content and low sedimentation rate were the main controlling factors for the higher content of rare earth elements. The major carrier was biogenic apatite (i.e., fish debris), and the REY from the seawater as well as pore water could be incorporated into the bioapatite during the early stage of diagenesis. Moreover, REE³⁺+Na⁺↔2Ca²⁺ and REE³⁺+Si⁴⁺↔Ca²⁺+P⁵⁺ may be substitution schemes in the bioapatite crystal lattice; however, this needs further research.
Key words:REYhost-phaseenrichments mechanismDeep-sea REY-rich mud





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