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.