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TitreLarge heat and fluid fluxes driven through mid-plate outcrops on ocean crust
AuteurHutnak, M; Fisher, A T; Harris, R; Stein, C; Wang, K; Spinelli, G; Schindler, M; Villinger, H; Silver, E
SourceNature Geoscience vol. 1, ngeo264, 2008, 4 pages, https://doi.org/10.1038/ngeo264 (Accès ouvert)
Année2008
Séries alt.Secteur des sciences de la Terre, Contribution externe 20070628
ÉditeurSpringer Nature
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1038/ngeo264
Mediapapier; en ligne; numérique
Formatspdf
Lat/Long OENS-88.0000 -86.0000 10.0000 8.0000
Sujetsflux thermique; conduction thermique; dorsales médio-océaniques; tectonique de plaques; milieux tectoniques; interprétations tectoniques; perméabilité; système hydrothermal; milieux marins; Plaque de Cocos ; géologie marine; tectonique
Illustrationssketch maps
ProgrammeRéduction des risques dus aux aléas naturels
Diffusé2008 08 01
Résumé(disponible en anglais seulement)
Seafloor hydrothermal circulation on ridge flanks, areas far from the magmatic influence of plate creation, extracts ~30% of oceanic lithospheric heat and impacts numerous tectonic, magmatic, and biogeochemical processes, but little is known about the magnitude of ridge-flank fluid and heat fluxes at a lithospheric scale. Quantifying hydrothermal fluxes at this scale has been limited by a lack of collocated bathymetric, seismic reflection, and heat flux data. We have collected and analyzed multiple data sets from a large area of 18-24 Ma seafloor, and have resolved massive flows of heat and fluid discharging from a few, widely-spaced crustal outcrops that penetrate seafloor sediments. The conductive seafloor heat flux through 14,500 km2 of the survey area is 10-40% of lithospheric, requiring an integrated advective power output of 800-1,400 MW. Scattered basalt outcrops in this area allow hydrothermal fluids to enter and exit the crust and bypass low-permeability sediments, with the smallest outcrops being favoured sites of fluid and advective heat discharge. Based on the inferred distribution and number of discharging outcrops, each discharging outcrop must convey 200-350 MW of heat from the crust to the ocean, equivalent to the heat output of a high-temperature black-smoker vent field, as typically seen in ridge-crest environments. Low
hydrothermal fluid temperatures (5-40°C) in this region require that at least 4-80 x 103 L/s of fluid must continuously enter and exit the crust regionally (1-20 x 103 L/s from each discharging outcrop) to sustain the advective heat output.
GEOSCAN ID225020