JpGU-AGU Joint Meeting 2017

講演情報

[JJ] ポスター発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS22] [JJ] 地球掘削科学

2017年5月24日(水) 13:45 〜 15:15 ポスター会場 (国際展示場 7ホール)

コンビーナ:山田 泰広(海洋研究開発機構 海洋掘削科学研究開発センター)、道林 克禎(静岡大学理学部地球科学科)、池原 実(高知大学海洋コア総合研究センター)、菅沼 悠介(国立極地研究所)

[MIS22-P13] 南太平洋環流域の堆積物に含まれる微小金属粒の鉱物学的・地球化学的特徴について(IODP Exp. 329)

*浦本 豪一郎1,2諸野 祐樹1富岡 尚敬1若木 重行1和穎 朗太3上杉 建太朗4竹内 晃久4星野 真人4鈴木 芳生4,5光延 聖6菅 大暉7宮本 千尋5高橋 嘉夫5稲垣 史生1 (1.海洋研究開発機構、2.高知大学、3.農業・食品産業技術総合研究機構、4.高輝度光科学研究センター、5.東京大学、6.愛媛大学、7.広島大学)

キーワード:微小鉱物粒、遠洋性粘土、南太平洋環流域

Ferromanganese minerals widely occur on the seafloor of abyssal plains as nodules consisting of manganese, iron and various trace metal elements. Accumulation and dissolution of the vast mineral deposits play important roles in the global element cycle. However, no clear picture has yet emerged as to the nature of these mineral deposits in deep subseafloor oxic sediments. During the Integrated Ocean Drilling Program (IODP) Expedition 329, we drilled the entire sedimentary sequence at 6 sites in the ultra-oligotrophic region of the South Pacific Gyre (SPG), where dissolved O2 and aerobic microbial communities are present from the seafloor to the sediment-basement interface [1]. We observed abundant micrometer-scale particles of ferromanganese minerals (Mn-microparticles) in oxic pelagic clay sediments of the SPG over 100 million years. Three-dimensional micro-texture and elemental composition analyses using mass-spectrometric, flow cytometry and synchrotron-based approaches revealed that most Mn-microparticles are poorly crystalline ferromanganese minerals that consist of various trace metals and carbon species, indicating that Mn-microparticles are possibly derived from the past hydrothermal activity and widespread buried in the open-ocean gyre.

[1] D’Hondt et al., Presence of oxygen and aerobic communities from seafloor to basement in deep-sea sediment. Nature Geosciences, 8(4), 299-304, 2015.