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dc.contributor.authorNaif, Samer  Concept link
dc.contributor.authorKey, Kerry  Concept link
dc.contributor.authorConstable, Steven  Concept link
dc.contributor.authorEvans, Rob L.  Concept link
dc.date.accessioned2015-11-09T19:20:36Z
dc.date.available2016-02-16T09:02:38Z
dc.date.issued2015-08-16
dc.identifier.citationGeochemistry, Geophysics, Geosystems 16 (2015): 2582–2597en_US
dc.identifier.urihttps://hdl.handle.net/1912/7615
dc.descriptionAuthor Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 16 (2015): 2582–2597, doi:10.1002/2015GC005927.en_US
dc.description.abstractThe portion of the Central American margin that encompasses Nicaragua is considered to represent an end-member system where multiple lines of evidence point to a substantial flux of subducted fluids. The seafloor spreading fabric of the incoming Cocos plate is oriented parallel to the trench such that flexural bending at the outer rise optimally reactivates a dense network of normal faults that extend several kilometers into the upper mantle. Bending faults are thought to provide fluid pathways that lead to serpentinization of the upper mantle. While geophysical anomalies detected beneath the outer rise have been interpreted as broad crustal and upper mantle hydration, no observational evidence exists to confirm that bending faults behave as fluid pathways. Here we use seafloor electromagnetic data collected across the Middle America Trench (MAT) offshore of Nicaragua to create a comprehensive electrical resistivity image that illuminates the infiltration of seawater along bending faults. We quantify porosity from the resistivity with Archie's law and find that our estimates for the abyssal plain oceanic crust are in good agreement with independent observations. As the Cocos crust traverses the outer rise, the porosity of the dikes and gabbros progressively increase from 2.7% and 0.7% to 4.8% and 1.7%, peaking within 20 km of the trench axis. We conclude that the intrusive crust subducts twice as much pore water as previously thought, significantly raising the flux of fluid to the seismogenic zone and the mantle wedge.en_US
dc.description.sponsorshipThis work was supported by National Science Foundation grants OCE-0841114 and OCE-0840894, and the Seafloor Electromagnetic Methods Consortium at Scripps Institution of Oceanography.en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.publisherJohn Wiley & Sonsen_US
dc.relation.urihttps://doi.org/10.1002/2015GC005927
dc.subjectSubduction zonesen_US
dc.subjectFluidsen_US
dc.subjectOceanic crusten_US
dc.subjectBending faultsen_US
dc.titleWater-rich bending faults at the Middle America Trenchen_US
dc.typeArticleen_US
dc.description.embargo2016-02-16en_US
dc.identifier.doi10.1002/2015GC005927


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