太平洋深海富稀土沉积物的分类及成因  

Classification and genesis of deep-sea REY-rich sediments in the Pacific Ocean

作　　者：王添翼 董彦辉 初凤友 石学法 李小虎 苏蓉[4] 章伟艳 WANG Tianyi;DONG Yanhui;CHU Fengyou;SHI Xuefa;LI Xiaohu;SU Rong;ZHANG Weiyan(School of Earth and Space Sciences,Peking University,Beijing 100871,China;Second Institute of Oceanography,Key Laboratory of Submarine Geosciences,MNR,Hangzhou 310012,China;First Institute of Oceanography,Key Laboratory of Marine Geology and Metallogeny,MNR,Qingdao 266100,China;College of Earth Sciences,Jilin University,Changchun 130000,China)

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]自然资源部第二海洋研究所海底科学重点实验室,浙江杭州310012 [3]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266100 [4]吉林大学地球科学学院,吉林长春130000

出　　处：《海洋学研究》2024年第1期23-35,共13页Journal of Marine Sciences

基　　金：浙江省基础公益研究计划(LGF22D06004);国家自然科学基金项目(U2244222);国际海底区域资源环境评价项目(DY135-N1-1-01,DY135-G2-1-03)。

摘　　要：深海富稀土沉积物广泛分布在西太平洋、东太平洋、东南太平洋、印度洋等地区。本研究对东太平洋克拉里昂-克里珀顿断裂带(Clarion-Clipperton Fracture Zone,简称CC区)的两个站位富稀土沉积物的矿物学与地球化学特征进行了分析,并收集了太平洋92个站位深海富稀土沉积物元素地球化学数据,依据地球化学特征,结合矿物组成,将太平洋深海富稀土沉积物分为富Al型、富Fe型、富Ba型等三个类型。富Al型富稀土沉积物广泛布在西太平洋地区,沉积物类型以沸石黏土为主,全岩Al_(2)O_(3)平均含量可达14.9%。富Fe型富稀土沉积物位于东太平洋海隆附近的东南太平洋和东北太平洋区域,沉积物中TFe_(2)O_(3)平均含量高达18.8%,部分样品呈现明显的Eu正异常,热液活动可能为稀土元素的富集提供了丰富的稀土元素及载体矿物。富Ba型富稀土沉积物主要分布于东太平洋CC区,沉积物类型主要是(含)硅质黏土,Ba平均含量可达8092×10^(-6)。高Ba含量指示了沉积物形成时期所在海域可能具有很高的初级生产力,这种环境条件形成了大量的生物磷灰石沉积,并与CC区渐新世以来强劲的底流耦合,进而增强了磷灰石的积累,促进了稀土的富集。Deep-sea REY-rich sediments that are rich in lanthanides and yttrium(REY)extensively distributed in regions such as the Western Pacific,Eastern Pacific,Southeastern Pacific,and the Indian Ocean.This study analyzed the mineralogical and geochemical characteristics of deep-sea REY-rich sediments from two sites in the Clarion-Clipperton Fracture Zone(CCFZ)of the Eastern Pacific.Additionally,geochemical data on elements from 92 deep-sea REY-rich sediment sites across the Pacific were collected.Based on geochemical characteristics in conjunction with mineral composition,the Pacific deep-sea REY-rich sediments are categorized into three types:Al-rich,Fe-rich,and Ba-rich.The Al-rich type,prevalent in the Western Pacific region,primarily consists of zeolite clay,with an average whole-rock Al_(2)O_(3)content reaching up to 14.9%.The Fe-rich type,found near the Eastern Pacific Rise in the Southeastern and Northeastern Pacific,exhibits a high average TFe_(2)O_(3)content of 18.8%.Some samples within this type show a significant positive Eu anomaly,indicating that hydrothermal activity may contribute to the enrichment of REY and associated carrier minerals.The Ba-rich type,mainly located in the CCFZ of the Eastern Pacific,consists predominantly of(siliceous)clay,with an average Ba content of approximately 8092×10^(-6).The elevated Ba levels suggest that the area of sediment formation may have experienced high primary productivity.This environmental condition likely resulted in extensive biogenic apatite deposition,which coupled with strong bottom currents in the CCFZ since the Oligocene,enhanced the accumulation of apatite,thereby promoting the enrichment of rare earth elements.

关 键 词：太平洋 富稀土沉积物 CC区 

分 类 号：P736.4[天文地球—海洋地质]