Enrichment and mineralization of rare earth elements in deep-sea sediments
Although China is a big country in resource of rare earth elements(REE),its resource of heavy rare earth elements(HREE)is still one of key metals in short supply.In 2011,Japanese scholar Kato and others published an article stating that large amounts of REE-rich sediments were discovered in the deep-sea basin of the Pacific Ocean.This news attracted great attention from countries around the world.Previous researches found that the REE-rich deep-sea sediment widely distributed on the seafloor is a type of strategic mineral resources.It is relatively enriched in key metals of the REE,especially the HREE.It is considered to be one of important marine mineral resources discovered after the ocean nodules and crusts,mid-ocean ridge hydrothermal sulfides,and natural gas hydrates.At present,it is confirmd that the REE-rich deep-sea sediment is distributed in some large areas of the Pacific and Indian oceans.Chinese scientists have initially classified four major exploration prospects of the deep-sea REE resource,including three prospects in the Pacific Ocean and one prospect in the Indian Ocean.Mineral components of the REE-rich sediment mainly include biogenic apatite(fish teeth and fish bones),micronodules(iron and manganese oxides or hydroxides),zeolites,clay minerals,etc.,among which the biogenic apatite is considered the most important carrier of the REE.Researches show that the REE was directly sourced from the overlying seawater and pore water of the sediment,but the REE contribution of hydrothermal fluids and volcanic activities to the sediment cannot be excluded.Water depth,sedimentation rate and redox environment are important factors controlling the enrichment of the REE in the deep-sea sediment.Changes of the terrestrial input caused by strong bottom currents,submarine volcanic and hydrothermal activities,and climate events also had important impacts on the enrichment of REE in the deep-sea sediment.Generally speaking,there are still some unsolved scientific problems in researches on the REE mineralization of the deep-sea sediment.,It is necessary to further strengthen the research on the genesis and super-normal REE enrichment mechanism of the REE-rich deep-sea sediment in the future,in order to improve the REE metallogenic model of the deep-sea sediment,and provide important references for China′s research and practice of the REE exploration in zones of the REE-rich deep-sea sediment.
NETL
NSTL
万方数据
维普
