Slab dehydration in warm subduction zones at depths of episodic slip and tremor

dc.citation.articleNumber116601en_US
dc.citation.journalTitleEarth and Planetary Science Lettersen_US
dc.citation.volumeNumber552en_US
dc.contributor.authorCondit, Cailey B.en_US
dc.contributor.authorGuevara, Victor E.en_US
dc.contributor.authorDelph, Jonathan R.en_US
dc.contributor.authorFrench, Melodie E.en_US
dc.date.accessioned2021-12-17T20:09:10Zen_US
dc.date.available2021-12-17T20:09:10Zen_US
dc.date.issued2020en_US
dc.description.abstractNon-volcanic tremor (NVT) and episodic slow slip events (SSEs) have been observed below the seismogenic zone of relatively warm subduction zones for the past 20 years. Geophysical and geologic observations show that this portion of the subduction interface is fluid-rich, and many models for these slip behaviors necessitate high pore fluid pressures. However, whether these fluids are sourced from local dehydration reactions in particular lithologies, or require up-dip transport from greater depths is not known. We present thermodynamic models of the petrologic evolution of four lithologies typical of the plate interface (average MORB, seafloor altered MORB, hydrated depleted MORB mantle, and metapelite) along predicted plate boundary pressure–temperature (P-T) paths at several warm subduction segments where NVT and SSEs are observed at depths between 25-65 km. The models suggest that 1-2 wt% H2O is released at the depths of NVT/SSEs in Jalisco-Colima, Guerrero, Cascadia, and Shikoku due to punctuated dehydration reactions within MORB, primarily through chlorite and/or lawsonite breakdown. These reactions produce sufficient in-situ fluid across a narrow P-T range to cause high pore fluid pressures at NVT/SSE depths. Dehydration of hydrated peridotite is minimal at these depths for most margins, and metapelite releases H2O (<1.5 wt%) gradually over a wide depth range compared to MORB. We posit that punctuated dehydration of oceanic crust provides the dominant source of fluids at the base of the seismogenic zone in these warm subduction zones, and up-dip migration of fluids from deeper in the subduction zone is not required.en_US
dc.identifier.citationCondit, Cailey B., Guevara, Victor E., Delph, Jonathan R., et al.. "Slab dehydration in warm subduction zones at depths of episodic slip and tremor." <i>Earth and Planetary Science Letters,</i> 552, (2020) Elsevier: https://doi.org/10.1016/j.epsl.2020.116601.en_US
dc.identifier.digital1-s2-0-S0012821X20305458-mainen_US
dc.identifier.doihttps://doi.org/10.1016/j.epsl.2020.116601en_US
dc.identifier.urihttps://hdl.handle.net/1911/111883en_US
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.rightsThis is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).en_US
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/).en_US
dc.titleSlab dehydration in warm subduction zones at depths of episodic slip and tremoren_US
dc.typeJournal articleen_US
dc.type.dcmiTexten_US
dc.type.publicationpublisher versionen_US
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