Smectite formation in metalliferous sediments near the East Pacific Rise at 13°N

IOCAS-IR

	Smectite formation in metalliferous sediments near the East Pacific Rise at 13°N
	RONG Kunbo ; ZENG Zhigang ; YIN Xuebo ; CHEN Shuai ; WANG Xiaoyuan ; QI Haiyan ; MA Yao
发表期刊	Acta Oceanologica Sinica
ISSN	0253-505X
	2018-09-15
出版年	2018
卷号	v.37 期号:09 页码:71-85
文献类型	CNKI期刊论文
摘要	A 43 cm long E271 sediment core collected near the East Pacific Rise(EPR) at 13°N were studied to investigate the origin of smectite for understanding better the geochemical behavior of hydrothermal material after deposition.E271 sediments are typical metalliferous sediments. After removal of organic matter, carbonate, biogenic opal,and Fe-Mn oxide by a series of chemical procedures, clay minerals(<2 μm) were investigated by X-ray diffraction,chemical analysis and Si isotope analysis. Due to the influence of seafloor hydrothermal activity and close to continent, the sources of clay minerals are complex. Illite, chlorite and kaolinite are suggested to be transported from either North or Central America by rivers or winds, but smectite is authigenic. It is enriched in iron, and its contents are highest in clay minerals. Data show that smectite is most likely formed by the reaction of hydrothermal Fe-oxyhydroxide with silica and seawater in metalliferous sediments. The Si that participates in this reaction may be derived from siliceous microfossils(diatoms or radiolarians), hydrothermal fluids, or detrital mineral phases. And their δ30 Si values are higher than those of authigenic smectites, which implies that a Si isotope fractionation occurs during the formation because of the selective absorption of light Si isotopes onto Feoxyhydroxides. Sm/Fe mass ratios(a proxy for overall REE/Fe ratio) in E271 clay minerals are lower than those in metalliferous sediments, as well as distal hydrothermal plume particles and terrigenous clay minerals. This result suggests that some REE are lost during the smectite formation, perhaps because their large ionic radii of REE scavenged by Fe-oxyhydroxides preclude substitution in either tetrahedral or octahedral lattice sites of this mineral structure, which decreases the value of metalliferous sediments as a potential resource for REE.
关键词	metalliferous sediments smectite formation REE silicon isotope
CNKI专辑号	A;
CNKI专辑名称	基础科学;
CNKI专题号	A010;A011;
CNKI专题名称	海洋学;地质学;
分类号	P736
收录类别	中科院核心 ; 中科院扩展
语种	英文;
资助项目(基金）	The National Natural Science Foundation of China under contract No.41325021 ; the National Basic Research Program(973 Program)of China under contract No.2013CB429700 ; the National Special Fund for the 12th Five-Year Plan of COMRA under contract No.DY125-12-R-02 ; the Special Fund for the Taishan Scholar Program of Shandong Province under contract No.ts201511061 ; the Ao Shan Talents Program Supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2015ASTP-0S17
文献类型	CNKI期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/188802
专题	中国科学院海洋研究所
作者单位	1.SeafloorHydrothermalActivityLaboratoryoftheKeyLaboratoryofMarineGeologyandEnvironment,InstituteofOceanology,ChineseAcademyofSciences 2.UniversityofChineseAcademyofSciences 3.LaboratoryforMarineMineralResources,QingdaoNationalLaboratoryforMarineScienceandTechnology
推荐引用方式 GB/T 7714	RONG Kunbo,ZENG Zhigang,YIN Xuebo,et al. Smectite formation in metalliferous sediments near the East Pacific Rise at 13°N. 2018.