Depth of oceanic-crust underplating in a subduction zone: Inferences from fluid-inclusion analyses of crack-seal veins
書誌事項
- 公開日
- 2003
- DOI
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- 10.1130/g19885.1
- 公開者
- Geological Society of America
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説明
Fluid inclusions in crack-seal veins are analyzed in accreted melange now on land. The vein I inclusions are observed in the necked parts of sandstone blocks in melange, and the vein II inclusions developed in shale below the thrust fault, which cuts the melanges. The pressure and temperature estimations from the inclusions within vein I show that the cracks were sealed at ;125-195 8C under ;92-144 MPa of fluid pressure. Vein II formed in cracks that might have opened in a damage zone caused by the thrust fault as it broke through oceanic crust and into the melange; these veins contain fluid inclusions trapped at ;135-245 8C under ;107-149 MPa of fluid pressure. The depth ( ;4-6 km below the seafloor) and temperature estimates are consistent with the conditions where an aseismic decollement within sedimentary rocks steps down into the oceanic basement, so that a thin section of oceanic crust underplates in the hanging wall. Such a step-down site is the updip limit of the seismogenic zone in the modern Nankai Trough.
収録刊行物
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- Geology
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Geology 31 (11), 1005-, 2003
Geological Society of America
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詳細情報 詳細情報について
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- CRID
- 1363670320143149184
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- DOI
- 10.1130/g19885.1
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- ISSN
- 00917613
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- データソース種別
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- Crossref
- OpenAIRE
