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Mantle hydration along outer-rise faults inferred from serpentinite permeability

Recent geophysical surveys indicate that hydration (serpentinization) of oceanic mantle is related to outer-rise faulting prior to subduction. The serpentinization of oceanic mantle influences the generation of intermediate-depth earthquakes and subduction water flux, thereby promoting arc volcanism...

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Detalles Bibliográficos
Autores principales: Hatakeyama, Kohei, Katayama, Ikuo, Hirauchi, Ken-ichi, Michibayashi, Katsuyoshi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5654952/
https://www.ncbi.nlm.nih.gov/pubmed/29066745
http://dx.doi.org/10.1038/s41598-017-14309-9
Descripción
Sumario:Recent geophysical surveys indicate that hydration (serpentinization) of oceanic mantle is related to outer-rise faulting prior to subduction. The serpentinization of oceanic mantle influences the generation of intermediate-depth earthquakes and subduction water flux, thereby promoting arc volcanism. Since the chemical reactions that produce serpentinite are geologically rapid at low temperatures, the flux of water delivery to the reaction front appears to control the lateral extent of serpentinization. In this study, we measured the permeability of low-temperature serpentinites composed of lizardite and chrysotile, and calculated the lateral extent of serpentinization along an outer-rise fault based on Darcy’s law. The experimental results indicate that serpentinization extends to a region several hundred meters wide in the direction normal to the outer-rise fault in the uppermost oceanic mantle. We calculated the global water flux carried by serpentinized oceanic mantle ranging from 1.7 × 10(11) to 2.4 × 10(12) kg/year, which is comparable or even higher than the water flux of hydrated oceanic crust.