Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches

17 pages, 11 figures, 1 table

Bibliographic Details
Authors: Lefeldt, M., Ranero, César R., Grevemeyer, Ingo
Format: article
Publication Date:2012
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/91911
Online Access:http://hdl.handle.net/10261/91911
Access Level:Open access
Keyword:Subduction zone
Water influx
Serpentinization
Oceanic plates
Microseismicity
Bending
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spelling Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenchesLefeldt, M.Ranero, César R.Grevemeyer, IngoSubduction zoneWater influxSerpentinizationOceanic platesMicroseismicityBending17 pages, 11 figures, 1 tableWater transported by slabs into the mantle at subduction zones plays key roles in tectonics, magmatism, fluid and volatiles fluxes, and most likely in the chemical evolution of the Earth’s oceans and mantle. Yet, incorporation of water into oceanic plates before subduction is a poorly understood process. Several studies suggest that plates may acquire most water at subduction trenches because the ocean crust and uppermost mantle there are intensely faulted caused by bending and/or slab pull, and display anomalously low seismic velocities. The low velocities are interpreted to arise from a combination of fluid-filled fractures associated to normal faulting and mineral transformation by hydration. Mantle hydration by transformation of nominally dry peridotite to water-rich serpentinite could potentially create the largest fluid reservoir in slabs and is therefore the most relevant for the transport of water in the deep mantle. The depth of fracturing by normal-fault earthquakes is usually not well constrained, but could potentially create deep percolation paths for water that might hydrate up to tens of kilometers into the mantle, restrained only by serpentine stability. Yet, interpretation of deep intraplate mineral alteration remains speculative because active-source seismic experiments have sampled only the uppermost few kilometers of mantle, leaving the depth-extent of anomalous velocities and their relation to faulting unconstrained. Here we use a joint inversion of activesource seismic data, and both local and regional earthquakes to map the three dimensional distribution of anomalous velocities under a seismic network deployed at the trench seafloor. We found that anomalous velocities are restrained to the depth of normal-fault micro-earthquake activity recorded in the network, and are considerably shallower than either the rupture depth of teleseismic, normal-fault earthquakes, or the limit of serpentine stability. Extensional micro-earthquakes indicate that each fault in the region slips every 2–3 months which may facilitate regular water percolation. Deeper, teleseismic earthquakes are comparatively infrequent, and possibly do not cause significant fracturing that remains open long enough to promote alteration detectable with our seismic study. Our results show that the stability field of serpentine does not constrain the depth of potential mantle hydrationThis publication is contribution 242 of the Sonderforschungsbereich 574 “Volatiles and Fluids in Subduction Zones” at Kiel UniversityPeer ReviewedAmerican Geophysical Union2014201420122014info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501http://hdl.handle.net/10261/91911reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttps://doi.org/10.1029/2012GC004043info:eu-repo/semantics/openAccessoai:digital.csic.es:10261/919112026-05-22T06:33:51Z
dc.title.none.fl_str_mv Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches
title Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches
spellingShingle Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches
Lefeldt, M.
Subduction zone
Water influx
Serpentinization
Oceanic plates
Microseismicity
Bending
title_short Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches
title_full Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches
title_fullStr Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches
title_full_unstemmed Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches
title_sort Seismic evidence of tectonic control on the depth of water influx into incoming oceanic plates at subduction trenches
dc.creator.none.fl_str_mv Lefeldt, M.
Ranero, César R.
Grevemeyer, Ingo
author Lefeldt, M.
author_facet Lefeldt, M.
Ranero, César R.
Grevemeyer, Ingo
author_role author
author2 Ranero, César R.
Grevemeyer, Ingo
author2_role author
author
dc.subject.none.fl_str_mv Subduction zone
Water influx
Serpentinization
Oceanic plates
Microseismicity
Bending
topic Subduction zone
Water influx
Serpentinization
Oceanic plates
Microseismicity
Bending
description 17 pages, 11 figures, 1 table
publishDate 2012
dc.date.none.fl_str_mv 2012
2014
2014
2014
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
format article
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/91911
url http://hdl.handle.net/10261/91911
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv https://doi.org/10.1029/2012GC004043
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv American Geophysical Union
publisher.none.fl_str_mv American Geophysical Union
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,812455

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