Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment

The crustal structure and topography of the Moho boundary beneath the Atlas Mountains of Morocco has been constrained by a controlled source, wide-angle seismic reflection transect: the SIMA experiment. This paper presents the first results of this project, consisting of an almost 700 km long, high-...

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Autores: Ayarza, P., Carbonell, Ramón, Teixell, A., Palomeras, Imma, Martí, David, Kchikach, A., Harnafi, M., Levander, A., Gallart Muset, Josep, Arboleya, M. L., Alcalde, Juan, Fernández Ortiga, Manel, Charroud, M., Amrhar, M.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2014
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/99678
Acceso en línea:http://hdl.handle.net/10261/99678
Access Level:acceso abierto
Palabra clave:asthenospheric upwelling
Atlas Mountains of Morocco
Crustal imbrication
low P-wave velocity
partial melt
wide-angle seismic reflection
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spelling Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experimentAyarza, P.Carbonell, RamónTeixell, A.Palomeras, ImmaMartí, DavidKchikach, A.Harnafi, M.Levander, A.Gallart Muset, JosepArboleya, M. L.Alcalde, JuanFernández Ortiga, ManelCharroud, M.Amrhar, M.asthenospheric upwellingAtlas Mountains of MoroccoCrustal imbricationlow P-wave velocitypartial meltwide-angle seismic reflectionThe crustal structure and topography of the Moho boundary beneath the Atlas Mountains of Morocco has been constrained by a controlled source, wide-angle seismic reflection transect: the SIMA experiment. This paper presents the first results of this project, consisting of an almost 700 km long, high-resolution seismic profile acquired from the Sahara craton across the High and the Middle Atlas and the Rif Mountains. The interpretation of this seismic data set is based on forward modeling by raytracing, and has resulted in a detailed crustal structure and velocity model for the Atlas Mountains. Results indicate that the High Atlas features a moderate crustal thickness, with the Moho located at a minimum depth of 35 km to the S and at around 31 km to the N, in the Middle Atlas. Upper crustal shortening is resolved at depth through a crustal root where the Saharan crust underthrusts the northern Moroccan crust. This feature defines a lower crust imbrication that, locally, places the Moho boundary at 40-41 km depth in the northern part of the High Atlas. The P-wave velocity model is characterized by relatively low velocities, mostly in the lower crust and upper mantle, when compared to other active orogens and continental regions. These low deep crustal velocities together with other geophysical observables such as conductivity estimates derived from MT measurements, moderate Bouguer gravity anomaly, high heat flow, and surface exposures of recent alkaline volcanism lead to a model where partial melts are currently emplaced at deep crustal levels and in the upper mantle. The resulting model supports the existence of a mantle upwelling as mechanism that would contribute significantly to sustain the High Atlas topography. However, the detailed Moho geometry deduced in this work should lead to a revision of the exact geometry and position of this mantle feature and will require new modeling effortsThis work has been primarily funded by the Spanish MEC project CGL2007–63889. Additional funding was provided by projects CGL2010–15416, CSD2006-00041, and GL2009–09727 (Spain), CGL2008–03474-E, 07-TOPO_EUROPE_FP-006 (ESF Eurocores) and EAR-0808939 (US, NSF).Peer reviewedAmerican Geophysical UnionConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]201420142014info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/99678reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://dx.doi.org/10.1002/2013GC005164Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/996782026-05-22T06:33:51Z
dc.title.none.fl_str_mv Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment
title Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment
spellingShingle Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment
Ayarza, P.
asthenospheric upwelling
Atlas Mountains of Morocco
Crustal imbrication
low P-wave velocity
partial melt
wide-angle seismic reflection
title_short Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment
title_full Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment
title_fullStr Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment
title_full_unstemmed Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment
title_sort Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment
dc.creator.none.fl_str_mv Ayarza, P.
Carbonell, Ramón
Teixell, A.
Palomeras, Imma
Martí, David
Kchikach, A.
Harnafi, M.
Levander, A.
Gallart Muset, Josep
Arboleya, M. L.
Alcalde, Juan
Fernández Ortiga, Manel
Charroud, M.
Amrhar, M.
author Ayarza, P.
author_facet Ayarza, P.
Carbonell, Ramón
Teixell, A.
Palomeras, Imma
Martí, David
Kchikach, A.
Harnafi, M.
Levander, A.
Gallart Muset, Josep
Arboleya, M. L.
Alcalde, Juan
Fernández Ortiga, Manel
Charroud, M.
Amrhar, M.
author_role author
author2 Carbonell, Ramón
Teixell, A.
Palomeras, Imma
Martí, David
Kchikach, A.
Harnafi, M.
Levander, A.
Gallart Muset, Josep
Arboleya, M. L.
Alcalde, Juan
Fernández Ortiga, Manel
Charroud, M.
Amrhar, M.
author2_role author
author
author
author
author
author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv asthenospheric upwelling
Atlas Mountains of Morocco
Crustal imbrication
low P-wave velocity
partial melt
wide-angle seismic reflection
topic asthenospheric upwelling
Atlas Mountains of Morocco
Crustal imbrication
low P-wave velocity
partial melt
wide-angle seismic reflection
description The crustal structure and topography of the Moho boundary beneath the Atlas Mountains of Morocco has been constrained by a controlled source, wide-angle seismic reflection transect: the SIMA experiment. This paper presents the first results of this project, consisting of an almost 700 km long, high-resolution seismic profile acquired from the Sahara craton across the High and the Middle Atlas and the Rif Mountains. The interpretation of this seismic data set is based on forward modeling by raytracing, and has resulted in a detailed crustal structure and velocity model for the Atlas Mountains. Results indicate that the High Atlas features a moderate crustal thickness, with the Moho located at a minimum depth of 35 km to the S and at around 31 km to the N, in the Middle Atlas. Upper crustal shortening is resolved at depth through a crustal root where the Saharan crust underthrusts the northern Moroccan crust. This feature defines a lower crust imbrication that, locally, places the Moho boundary at 40-41 km depth in the northern part of the High Atlas. The P-wave velocity model is characterized by relatively low velocities, mostly in the lower crust and upper mantle, when compared to other active orogens and continental regions. These low deep crustal velocities together with other geophysical observables such as conductivity estimates derived from MT measurements, moderate Bouguer gravity anomaly, high heat flow, and surface exposures of recent alkaline volcanism lead to a model where partial melts are currently emplaced at deep crustal levels and in the upper mantle. The resulting model supports the existence of a mantle upwelling as mechanism that would contribute significantly to sustain the High Atlas topography. However, the detailed Moho geometry deduced in this work should lead to a revision of the exact geometry and position of this mantle feature and will require new modeling efforts
publishDate 2014
dc.date.none.fl_str_mv 2014
2014
2014
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/99678
url http://hdl.handle.net/10261/99678
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://dx.doi.org/10.1002/2013GC005164
Sí
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 15.812429

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