东南太平洋富稀土沉积早期成岩过程研究及其指示意义  

The study on the early diagenetic processes in REY-rich sediments in Southeast Pacific Ocean and its indicative significance

作　　者：李杰军 刘洪娜 王小静 李力 石学法 Li Jiejun;Liu Hongna;Wang Xiaojing;Li Li;Shi Xuefa(Key Laboratory of Marine Geology and Metallogeny,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;Laboratory for Marine Geology,Laoshan Laboratory,Qingdao 266237,China;Key Laboratory of Deep Sea Mineral Re-sources Development,Shandong(preparatory),Qingdao 266061,China)

机构地区：[1]自然资源部第一海洋研究所海洋地质与成矿作用重点实验室,山东青岛266061 [2]崂山实验室海洋地质过程与环境功能实验室,山东青岛266237 [3]山东省深海矿产资源开发重点实验室,山东青岛266061

出　　处：《海洋学报》2024年第2期40-51,共12页

基　　金：国家自然科学基金(42076046,91858209);国际海域资源调查与开发“十三五”项目(DY135-R2-1);山东泰山学者攀登计划资助项目(tspd20181216)。

摘　　要：富稀土深海沉积物作为一种潜在矿产资源,近年来备受关注。研究发现,稀土元素(REY)和钇(Y)元素的富集过程很可能发生在沉积物-海水界面(SWI),但目前针对富稀土沉积物的早期成岩过程研究较少。本研究采集了东南太平洋富稀土海区两个站位的沉积物短柱,解析了REY在SWI的早期成岩过程及其对REY在沉积物中富集机制的影响。孔隙水中较低的Fe、Mn和较高的Mo、U、V浓度表明研究区沉积物处于氧化环境。对比底层海水中REY,孔隙水中的REY呈中稀土(MREE)富集特征。沉积物中REY的主要富集相态为磷酸盐相,而孔隙水中REY及其配分模式可能受控于沉积物中磷酸盐的含量。本研究表明,在稀土元素早期成岩过程中,原本与铁锰相等其他相态结合的REY重新进入到孔隙水中,最终被磷酸盐相吸附和埋藏,早期成岩过程是深海沉积物中REY富集的重要机制。As potential mineral resources,rare earth elements(REY)and yttrium enriched sediments in the deep sea have attracted a lot of attention in recent years.It has been shown by studies that the enrichment process of REY is most likely to occur at the sediment-water interface(SWI),however studies on the early diagenetic processes in REY-enriched sediments are in general lacking.In this paper,we collected two short sediment cores in REY-enriched sediments in the Southeast Pacific Ocean,then we had conducted an in-depth analysis on the early diagenesis process of REY at SWI and its influence on the enrichment mechanism of REY in deep-sea sediment.The low Fe,Mn concentration and high Mo,U and V concentration in pore-water indicated that the sediment cores were in oxic environment.Compared to the REY in overlying water column,the dissolved REY in pore-water characterized by a middle rare earth elements(MREE).In sediment,phosphate phase is the main phase of REY,while the distribution pattern of REY in pore-water may be controlled by the phosphate content in sediments.Our results show that during the early diagenetic processes,the REY initially combined with Fe/Mn phase and other phases re-released into the pore-water,which is subsequently adsorbed by and eventually buried with the phosphate phase.Therefore,the early diagenetic process is an important mechanism of REY enrichment in deep sea sediments.

关 键 词：早期成岩 孔隙水 稀土元素 沉积物 东南太平洋 

分 类 号：P736.41[天文地球—海洋地质]