深海稀土分布规律与成矿作用

深海稀土是近年发现的一种富集中-重稀土的新型海洋矿产资源，其资源量远超陆地稀土储量，具有重要的潜在应用价值。中国是继日本之后在国际上第二个开展深海稀土调查研究的国家，2011年以来，先后在中印度洋海盆、东南太平洋和西太平洋深海盆地发现了大面积富稀土沉积区，在全球大洋中初步划分出4个深海稀土成矿带：西太平洋深海稀土成矿带、中—东太平洋深海稀土成矿带、东南太平洋深海稀土成矿带和中印度洋海盆-沃顿海盆深海稀土成矿带。深海富稀土沉积主要发育在深海盆地的沸石粘土和远洋粘土中，属于自生成因；部分发育在洋中脊附近的盆地中，受到热液作用的影响。研究发现，深海粘土中稀土元素主要赋存于生物磷灰石中，海水是稀土元素的主要来源；在早期成岩阶段，稀土元素在深海沉积物中发生转移和重新分配，并最终富集于生物磷灰石中；大水深（CCD面之下）、低沉积速率和强底流活动是深海稀土大规模成矿的主要控制因素。今后需要继续加大深海稀土基础调查，加强深海稀土调查探测技术研发，并开展海陆稀土成矿作用对比研究，揭示深海稀土成矿机制和规律。

Distribution and metallogenesis of deep-sea rare earth elements

Rare earth elements and yttrium(REY) in the deep-sea sediment is a new type of marine mineral resource rich in middle-heavy rare earth discovered in recent years.The amount of REY in the deep sea sediment is far more than the terrestrial rare earth reserves, and it has important potential application value.China is the second country after Japan to conduct deep-sea REY survey and research.Since 2011, large areas of REY-rich sediments have successively been found in the central India Ocean, the southeast and western Pacific Ocean.The global ocean is divided into four REY metallogenic belts, namely the western Pacific Ocean one, the central and eastern Pacific Ocean one, the southeast Pacific Ocean one, and the central Indian Ocean-Wharton basin one.The deep-sea REY-rich sediments are mainly developed in the zeolite clay and pelagic clay in the deep-sea basin, which is of autogenetic origin.While some of them are developed near the mid-ocean ridge and are affected by the hydrothermal processes.It is found that the REY in deep-sea clay mainly occur in biological apatite, and seawater is the main source of REY.In the early diagenetic stage, REY was transferred and redistributed in deep-sea sediments, and finally enriched in biological apatite.It is suggested that low sedimentation rate and vigorous bottom currents are principal controlling factors for large-scale deep-sea REY mineralization in the deep water-depth(beneath the carbonate compensation depth).In the future, it is necessary to continue to increase the basic deep-sea REY survey, strengthen the research and development of deep-sea REY detection technology, and carry out the comparative study of marine and terrestrial REY mineralization, so as to reveal the deep-sea REY mineralization mechanism and regularity.