[B-PT23] 地球史解読：冥王代から現代まで

[BPT23-23] 南鳥島超高濃度レアアース泥の分布と地球化学的特徴

*藤永 公一郎¹、中村 謙太郎¹、町田 嗣樹²、高谷 雄太郎³、安川 和孝¹、大田 隼一郎¹、荒木 修平¹、劉 漢捷¹、宇佐美 諒¹、南谷 祐資¹、牧 亮太¹、足立 遼介¹、大矢 和孝¹、渡辺 亮太²、西尾 嘉朗³、正木 裕香³、臼井 洋一³、原口 悟³、飯島 耕一³、鈴木 勝彦³、加藤 泰浩¹、MR14-E02 乗船者一同 ³ (1.東京大学工学系研究科、2.早稲田大学、3.海洋研究開発機構)

キーワード：レアアース, レアアース泥, 南鳥島, 海底鉱物資源

A recent report has documented the wide distribution of “REY-rich mud”, deep-sea sediment containing high concentrations of REY (ΣREY = 400–2000 ppm), in the Pacific Ocean (Kato et al., 2011). In 2013, we have discovered the “highly” (ΣREY = 2000–5000 ppm) to “extremely” (ΣREY > 5000 ppm) REY-rich mud in the Japanese Exclusive Economic Zone (EEZ) around Minamitorishima Island (Kato et al., 2013; Fujinaga et al., 2013; Suzuki et al., 2013). To investigate the detailed distribution of extremely REY-rich mud, we conducted the new research cruise (MR14-E02 by R/V Mirai from October 14 to 29, 2014) in the south region of the Minamitorishima EEZ. We collected 11 sediment cores by piston coring in this cruise. Here we report the distribution, bulk-sediment chemical compositions, and geochemical features of the extremely REY-rich mud in the Minamitorishima EEZ.