水曜海山海底熱水活動域の地下地質構造と硫化物硫黄同位体組成との関係
書誌事項
- タイトル別名
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- Geological Structure of the Subsurface Region at the Suiyo Seamount and its Relationship to Sulfur Isotope Compositions of Sulfides
説明
The active submarine hydrothermal field of Suiyo Seamount was directly drilled in order to understand the geological structure and hydrothermal processes at the subsurface region. A contrasting geological structure was found between the central and eastern areas. A thick accumulation of volcanoclastic sediments on the seafloor is a notable feature of the central area. These sediments were extensively altered by hydrothermal fluids and heavily cemented by anhydrite. Networks of hydrothermal veins and vesicles are developed in this cemented zone. This cementing process isolates the reducing subsurface environment from the oxic seawater environment. In contrast, less porous dacite lavas and breccia are main constituents of the eastern area. Hydrothermal fluids migrate along fractures developed in dacite lavas and breccia at the eastern hydrothermal area. Analyses of sulfur isotope compositions were performed on sulfide minerals separated from drilled core samples. Sulfur isotope compositions of the eastern samples (APSK01) are rather homogeneous, ranging from +1.0 to +1.3‰. These homogenized values suggest simple precipitation of sulfides using isotopically homogeneous H2S. Sulfur isotope compositions of sulfides from the central area are heterogeneous, ranging from +0.9 to +5.3‰. This indicates that isotope exchange occurred directly or indirectly between seawater sulfate and hydrothermal sulfides. Such regional difference in sulfur isotope compositions is tightly related to the difference in subsurface geological structure between the eastern and central regions of the Suiyo Seamount.
収録刊行物
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- 海の研究
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海の研究 14 (2), 221-235, 2005
日本海洋学会
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詳細情報 詳細情報について
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- CRID
- 1390001204380692352
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- NII論文ID
- 130004387692
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- ISSN
- 21863105
- 09168362
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- 本文言語コード
- ja
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- データソース種別
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- JaLC
- Crossref
- CiNii Articles
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- 抄録ライセンスフラグ
- 使用不可
