Fe-Si-Mn-oxyhydroxide encrustations on basalts at east pacific rise near 13A degrees N: An SEM-EDS study

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	Fe-Si-Mn-oxyhydroxide encrustations on basalts at east pacific rise near 13A degrees N: An SEM-EDS study
	Wang Xiaoyuan 1; Zeng Zhigang 1; Qi Haiyan 1; Chen Shuai 1; Yin Xuebo 1; Yang Baoju1,2
刊名	JOURNAL OF OCEAN UNIVERSITY OF CHINA
	2014-12-01
卷号	13 期号:6 页码:917-925
关键词	East Pacific Rise Fe-Si-Mn encrustations origin pillow basalt
通讯作者	Zeng, ZG (reprint author), Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China.
英文摘要	Fe-Si-Mn-oxyhydroxide encrustations at the East Pacific Rise (EPR) near 13A degrees N were analyzed using the scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS). These encrustations are mainly composed of amorphous Fe-Si-Mn-oxyhydroxides forming laminated, spherical, porous aggregates with some biodetritus, anhydrite, nontronite, and feldspar particles. Anhydrite particles and nontronite crystals in the Fe-Si-Mn-oxyhydroxide encrustations imply that the Fe-Si-Mn-oxyhydroxide may have formed under relatively low- to high-temperature hydrothermal conditions. The Fe-Si-Mn-oxyhydroxide encrustations on pillow basalts are 1-2 mm thick. The growth rate of ferromanganese crusts in the survey area suggests that these encrustations are an unlikely result of hydrogenic deposition alone having a hydrothermal and (Fe/Mn ratio up to 7.7 and Fe/(Fe+Mn+Al) ratio exceeding 0.78) hydrogenic origin (0.22 Fe/Mn ratio close to the mean value of 0.7 for open-ocean seamount crusts). The varying Fe/Mn ratios indicate that the Fe-Si-Mn-oxyhydroxide encrustations have formed through several stages of seafloor hydrothermalism. It is suggested that, at the initial formation stage, dense Fe-Si-oxyhydroxides with low Mn content deposit from a relatively reducing hydrothermal fluid, and then the loose Fe-Si-Mn-oxyhydroxides deposit on the Fe-Si-oxyhydroxides. As the oxidation degree of hydrothermal fluid increases and Si-oxide is inhibited, Mn-oxide will precipitate with Fe-oxyhydroxides.
学科主题	Oceanography
收录类别	SCI
语种	英语
WOS记录号	WOS:000344788700005
内容类型	期刊论文
源URL	[http://ir.qdio.ac.cn/handle/337002/23812]
专题	海洋研究所_海洋地质与环境重点实验室
作者单位	1.Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Wang Xiaoyuan,Zeng Zhigang,Qi Haiyan,et al. Fe-Si-Mn-oxyhydroxide encrustations on basalts at east pacific rise near 13A degrees N: An SEM-EDS study[J]. JOURNAL OF OCEAN UNIVERSITY OF CHINA,2014,13(6):917-925.
APA	Wang Xiaoyuan,Zeng Zhigang,Qi Haiyan,Chen Shuai,Yin Xuebo,&Yang Baoju.(2014).Fe-Si-Mn-oxyhydroxide encrustations on basalts at east pacific rise near 13A degrees N: An SEM-EDS study.JOURNAL OF OCEAN UNIVERSITY OF CHINA,13(6),917-925.
MLA	Wang Xiaoyuan,et al."Fe-Si-Mn-oxyhydroxide encrustations on basalts at east pacific rise near 13A degrees N: An SEM-EDS study".JOURNAL OF OCEAN UNIVERSITY OF CHINA 13.6(2014):917-925.