Permeability Structure of the Lava‐Dike Transition of 15‐Myr‐Old Oceanic Crust Formed at the East Pacific Rise

Abstract The permeability structure of oceanic crust controls both the spatial and temporal extent of hydrothermal circulation, but the detailed geometry of fractures in seafloor rocks is not well known. We apply an equivalent channel model to veins, joints, faults, and breccias preserved in recover...

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Main Authors: L. A. Gilbert, L. Crispini, P. Tartarotti, M. L. Bona
Format: Article
Language:English
Published: Wiley 2018-09-01
Series:Geochemistry, Geophysics, Geosystems
Subjects:
Online Access:https://doi.org/10.1029/2018GC007696
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author L. A. Gilbert
L. Crispini
P. Tartarotti
M. L. Bona
author_facet L. A. Gilbert
L. Crispini
P. Tartarotti
M. L. Bona
author_sort L. A. Gilbert
collection DOAJ
description Abstract The permeability structure of oceanic crust controls both the spatial and temporal extent of hydrothermal circulation, but the detailed geometry of fractures in seafloor rocks is not well known. We apply an equivalent channel model to veins, joints, faults, and breccias preserved in recovered cores from ODP‐IODP Hole 1256D to calculate paleo‐permeability. In the ~250‐m transition between dikes and lavas, paleo‐permeability is 10−13~10−14 m2 with narrow zones of >10−9 m2 that presumably act as conduits for the largest volume of fluids. Most of these high‐permeability zones are oriented vertically as a result of diking events into a significant thickness of lavas outside of the neovolcanic zone. After an increase in permeability due to off‐axis diking events, fluid temperatures drop, pathways are sealed, and the permeability of the upper oceanic crust drops significantly.
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spelling doaj-art-308eee416a3e4557b81ab8bee4311c442025-08-20T03:24:47ZengWileyGeochemistry, Geophysics, Geosystems1525-20272018-09-011993555356910.1029/2018GC007696Permeability Structure of the Lava‐Dike Transition of 15‐Myr‐Old Oceanic Crust Formed at the East Pacific RiseL. A. Gilbert0L. Crispini1P. Tartarotti2M. L. Bona3Geoscience and Marine Science at Williams‐Mystic, Williams College Williamstown MA USADipartimento di Scienze della Terra, dell'Ambiente e della Vita Università degli Studi di Genova Genoa ItalyDipartimento di Scienze della Terra Università degli Studi di Milano Milan ItalyGeoscience and Marine Science at Williams‐Mystic, Williams College Williamstown MA USAAbstract The permeability structure of oceanic crust controls both the spatial and temporal extent of hydrothermal circulation, but the detailed geometry of fractures in seafloor rocks is not well known. We apply an equivalent channel model to veins, joints, faults, and breccias preserved in recovered cores from ODP‐IODP Hole 1256D to calculate paleo‐permeability. In the ~250‐m transition between dikes and lavas, paleo‐permeability is 10−13~10−14 m2 with narrow zones of >10−9 m2 that presumably act as conduits for the largest volume of fluids. Most of these high‐permeability zones are oriented vertically as a result of diking events into a significant thickness of lavas outside of the neovolcanic zone. After an increase in permeability due to off‐axis diking events, fluid temperatures drop, pathways are sealed, and the permeability of the upper oceanic crust drops significantly.https://doi.org/10.1029/2018GC007696permeabilityseafloorIODP hole 1256Doceanic crustal evolution
spellingShingle L. A. Gilbert
L. Crispini
P. Tartarotti
M. L. Bona
Permeability Structure of the Lava‐Dike Transition of 15‐Myr‐Old Oceanic Crust Formed at the East Pacific Rise
Geochemistry, Geophysics, Geosystems
permeability
seafloor
IODP hole 1256D
oceanic crustal evolution
title Permeability Structure of the Lava‐Dike Transition of 15‐Myr‐Old Oceanic Crust Formed at the East Pacific Rise
title_full Permeability Structure of the Lava‐Dike Transition of 15‐Myr‐Old Oceanic Crust Formed at the East Pacific Rise
title_fullStr Permeability Structure of the Lava‐Dike Transition of 15‐Myr‐Old Oceanic Crust Formed at the East Pacific Rise
title_full_unstemmed Permeability Structure of the Lava‐Dike Transition of 15‐Myr‐Old Oceanic Crust Formed at the East Pacific Rise
title_short Permeability Structure of the Lava‐Dike Transition of 15‐Myr‐Old Oceanic Crust Formed at the East Pacific Rise
title_sort permeability structure of the lava dike transition of 15 myr old oceanic crust formed at the east pacific rise
topic permeability
seafloor
IODP hole 1256D
oceanic crustal evolution
url https://doi.org/10.1029/2018GC007696
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AT lcrispini permeabilitystructureofthelavadiketransitionof15myroldoceaniccrustformedattheeastpacificrise
AT ptartarotti permeabilitystructureofthelavadiketransitionof15myroldoceaniccrustformedattheeastpacificrise
AT mlbona permeabilitystructureofthelavadiketransitionof15myroldoceaniccrustformedattheeastpacificrise