Japan Geoscience Union Meeting 2019

Presentation information

[J] Poster

M (Multidisciplinary and Interdisciplinary) » M-GI General Geosciences, Information Geosciences & Simulations

[M-GI34] Marine Manganese Minerals

Tue. May 28, 2019 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Akira Usui(Marine Core Research Center, Kochi University), Yoshio Takahashi(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo), Katsuhiko Suzuki(Research and Development Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology), Takashi Ito(Faculty of Education, Ibaraki University)

[MGI34-P03] Geochemical characteristics of the nuclei of ferromanganese nodules in the Minamitorishima EEZ

*Daiki Terauchi1, Kentaro Nakamura1, Ryo Shimomura1, Koichi Horinouchi1, Kazutaka Yasukawa1,2, Shiki Machida2,1, Yasuhiro Kato1,2,3 (1.Department of Systems Innovation, School of Engineering, University of Tokyo, 2.Ocean Resources Research Center for Next Generation, Chiba Institute of Technology, 3.Frontier Research Center for Energy and Resources, School of Engineering, The University of Tokyo)

Keywords:ferromanganese nodules, nuclei, consolidated pelagic clay, chemical composition, Minamitorishima EEZ

Ferromanganese nodules are polymetallic concretion mainly composed of Mn- and Fe-oxyhydroxides with significant concentrations of valuable metals such as Ni, Cu and Co [1, 2]. The nodules can be found on deep-sea sediments worldwide, and their dense distribution has recently been discovered in the Japanese exclusive economic zone (EEZ) around Minamitorishima Island [3, 4].

It is well known that almost all ferromanganese nodules have nuclei, which clearly indicates that growth of a nodule generally starts on nucleus surface. Characterizing the nuclei of the nodules can, thus, provide important information on the conditions for the growth initiation of the nodules. Previous study [5] revealed that the nuclei of the nodules in the Minamitorishima EEZ can be classified into four types (nucleus I ~ IV), and that the majority of the nuclei is consolidated pelagic clay (nucleus I). However, detailed chemical characteristics of the nucleus I, as well as those of the other types of nuclei, have not yet been fully understood.

Here, we performed major and trace element analysis of the nuclei (especially of the nucleus I) in order to reveal their chemical features. In the presentation, we will show the results of the chemical characterization of the nuclei and then will discuss the origin of the nuclei of ferromanganese nodules in the Minamitorishima EEZ.

[1] Petersen et al. (2016) Marine Policy, 70, 175–187, [2] Hein et al. (2013) Ore Geology Reviews, 51, 1–14, [3] Machida et al. (2016) Geochemical Journal, 50, 539–555, [4] JAMSTEC press release, August 26, 2016, [5] Shimomura et al. (2018) JpGU meeting 2018.