Rare-earth, major, and trace element geochemistry of deep-sea sediments in the Indian Ocean; implications for the potential distribution of REY-rich mud in the Indian Ocean

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doi: 10.2343/geochemj.2.0361
Author(s): Yasukawa, Kazutaka; Nakamura, Kentaro; Fujinaga, Koichiro; Machida, Shiki; Ohta, Junichiro; Takaya, Yutaro; Kato, Yasuhiro
Author Affiliation(s): Primary:
University of Tokyo, Department of Systems Innovation, Tokyo, Japan
Japan Agency for Marine-Earth Science and Technology, Japan
Waseda University, Japan
Volume Title: Front edge of submarine mineral resources research in Japan
Volume Author(s): Suzuki, Katsuhiko, prefacer; Ishibashi, Jun-ichiro; Kato, Yasuhiro; Nozaki, Tatsuo
Source: Front edge of submarine mineral resources research in Japan, prefaced by Katsuhiko Suzuki, Jun-ichiro Ishibashi, Yasuhiro Kato and Tatsuo Nozaki. Geochemical Journal, 49(6), p.621-635. Publisher: Geochemical Society of Japan, Nagoya, Japan. ISSN: 0016-7002 CODEN: GEJOBE
Note: In English. 68 refs.; illus., incl. 1 table, sketch maps
Summary: We analyzed 1338 deep-sea sediment samples from 19 Deep Sea Drilling Project/Ocean Drilling Program sites covering a large portion of the Indian Ocean, and constructed a new and comprehensive data set of their bulk chemical compositions, including rare-earth, major, and trace elements. The bulk-sediment rare-earth and yttrium (REY) composition of the REY-enriched samples, characterized by relatively small negative Ce anomalies, almost no Y anomalies, and enrichment in heavy rare-earth elements, can be interpreted as the superposition of the REY compositions of apatite and hydrogenous Fe-Mn oxides. Although the hydrothermal component is a key factor in the formation of REY-rich mud in the Pacific Ocean, it is less important in the Indian Ocean, probably because there is less hydrothermal input of Fe-oxyhydroxides from seafloor hydrothermal vents there. The relationships among Fe2O3, MnO, P2O5, Co, and total REY contents suggest that a primary factor controlling REY enrichment in deep-sea sediments is the sedimentation rate. A low sedimentation rate allows both fish debris apatite and hydrogenous Fe-Mn (oxyhydr)oxides to accumulate in the surface sediments. On the basis of these results, we identified two potential areas in the Indian Ocean where REY-rich mud may be present in surface sediments: the south-southeastern Wharton Basin and the southern Central Indian Ocean Basin. The resource potential of the latter area might be particularly high if the distributions of REY-rich mud and Fe-Mn nodule fields broadly overlap.
Year of Publication: 2015
Research Program: DSDP Deep Sea Drilling Project
ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 27 Economic Geology, Metals; Arabian Sea; Cerium; Cores; DSDP Site 223; DSDP Site 238; DSDP Site 254; Deep Sea Drilling Project; Deep-sea environment; Distribution; Geochemical anomalies; Hydrothermal vents; Hydroxides; Indian Ocean; Iron oxyhydroxides; Kerguelen Plateau; Leg 119; Leg 189; Leg 23; Leg 24; Leg 26; Major elements; Marine environment; Marine sediments; Metal ores; Metals; Mineral exploration; Mineral resources; Ninetyeast Ridge; Nodules; ODP Site 1171; ODP Site 738; Ocean Drilling Program; Ocean floors; Oxides; Oxyhydroxides; Pacific Ocean; Potential deposits; Rare earths; Sedimentation rates; Sediments; South Pacific; Southern Ocean; Southwest Pacific; Tasman Sea; Trace elements; West Pacific; Wharton Basin; Yttrium
Coordinates: N060000 N220000 E0730000 E0380000
S120000 N150000 E0710000 E0480000
S483000 S423000 E1500000 E1440000
S684114 S492407 E0855147 E0713936
Record ID: 2017042805
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