[M-ZZ47] 海底マンガン鉱床の生成環境と探査・開発

[MZZ47-P10] SEM-EDSおよびµXRFによる南鳥島EEZマンガンノジュールの核の元素マッピング

*矢崎 誠¹、中村 謙太郎^1,2、町田 嗣樹²、安川 和孝^3,1、藤永 公一郎^2,3、加藤 泰浩^3,1,2 (1.東京大学大学院工学系研究科システム創成学専攻、2.千葉工業大学次世代海洋資源研究センター、3.東京大学大学院工学系研究科エネルギー・資源フロンティアセンター)

キーワード：鉄マンガンノジュール、核、元素マッピング、SEM-EDS、μXRF、南鳥島EEZ

Ferromanganese (Fe–Mn) nodules, one of the major submarine mineral resources, are attracting attention as a future metal source because they are rich in variety of industrially valuable metals such as Cu, Ni, and Co [1, 2]. Recently, the extensive and dense distribution of the Fe–Mn nodules has been discovered in the Japanese exclusive economic zone (EEZ) around Minamitorishima Island [3, 4]. To narrow down promising areas for future development of the nodules, it is important to understand the formation environment and the controlling factors of distribution of the Fe–Mn nodules.

Ferromanganese nodules start to grow around nuclei, and thus detailed characterization of the nuclei can be expected to provide important information on the conditions for the growth initiation of the nodules. Previous studies by X-ray CT scanning and ICP-MS analyses have revealed that the nuclei of the Minamitorishima nodules are highly varied in structure and chemical composition [5, 6]. However, detailed petrological characteristics and origin of those nuclei have not yet been clarified.

In this study, therefore, we performed high-resolution elemental mapping of the nuclei using SEM-EDS and μXRF. In the presentation, we will show the results of the elemental mapping of the nuclei and then will discuss the petrological characteristics and origin of the nuclei of Fe–Mn nodules in the Minamitorishima EEZ.


References
[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] Machida et al. (2021) Marine Georesources & Geotechnology, 39, 267–279
[5] Shimomura et al. (2018) JpGU meeting 2018.
[6] Terauchi et al. (2019) JpGU meeting 2019.