Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean
Autor(a) principal: | |
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Data de Publicação: | 2008 |
Outros Autores: | , , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Revista Brasileira de Geofísica (Online) |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-261X2008000100006 |
Resumo: | This paper presents geophysical and geochemical evidence for the possible existence of cold, subducted lithosphere beneath the Saint Paul Fracture Zone of the Equatorial Atlantic Ocean. The ocean floor along the fracture zone is characterized by a high percentage of abyssal peridotites. The abyssal peridotites were emplaced by tectonic uplift of the oceanic lithosphere. The top of the ridge is exposed at Saint Peter and Saint Paul islets. The Os isotopic composition of these abyssal peridotites indicate the presence of old depleted mantle material in this region with Re-depletion model ages (T RD) from 0.32 to 1.1Ga. Melt inclusions in plagioclase phenocrysts of the MORB close to this location have boninitic composition, suggesting that some basalts originated from low-degree mantle melting. The global tomography models show fast seismic velocities in the upper and lower mantle of the Equatorial Atlantic Ocean, consistent with the presence of cold subducted lithosphere. The range of Re-depletion model ages are consistent with paleo-reconstructions of plate motion, suggesting that the fossil subducted slab was formed during the closure of both the Iapetus and the Rheic oceans. |
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Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic OceanEquatorial Atlantic OceanSaint Paul Fracture Zoneabyssal mantleRe-Os isotope systemcold mantlefossil subducted slabThis paper presents geophysical and geochemical evidence for the possible existence of cold, subducted lithosphere beneath the Saint Paul Fracture Zone of the Equatorial Atlantic Ocean. The ocean floor along the fracture zone is characterized by a high percentage of abyssal peridotites. The abyssal peridotites were emplaced by tectonic uplift of the oceanic lithosphere. The top of the ridge is exposed at Saint Peter and Saint Paul islets. The Os isotopic composition of these abyssal peridotites indicate the presence of old depleted mantle material in this region with Re-depletion model ages (T RD) from 0.32 to 1.1Ga. Melt inclusions in plagioclase phenocrysts of the MORB close to this location have boninitic composition, suggesting that some basalts originated from low-degree mantle melting. The global tomography models show fast seismic velocities in the upper and lower mantle of the Equatorial Atlantic Ocean, consistent with the presence of cold subducted lithosphere. The range of Re-depletion model ages are consistent with paleo-reconstructions of plate motion, suggesting that the fossil subducted slab was formed during the closure of both the Iapetus and the Rheic oceans.Sociedade Brasileira de Geofísica2008-03-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-261X2008000100006Revista Brasileira de Geofísica v.26 n.1 2008reponame:Revista Brasileira de Geofísica (Online)instname:Sociedade Brasileira de Geofísica (SBG)instacron:SBG10.1590/S0102-261X2008000100006info:eu-repo/semantics/openAccessSichel,Susanna EleonoraEsperança,SoniaMotoki,AkihisaMaia,MarciaHoran,Mary F.Szatmari,PeterAlves,Eliane da CostaMello,Sidney L.M.eng2008-06-17T00:00:00Zoai:scielo:S0102-261X2008000100006Revistahttp://www.scielo.br/rbgONGhttps://old.scielo.br/oai/scielo-oai.php||sbgf@sbgf.org.br1809-45110102-261Xopendoar:2008-06-17T00:00Revista Brasileira de Geofísica (Online) - Sociedade Brasileira de Geofísica (SBG)false |
dc.title.none.fl_str_mv |
Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean |
title |
Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean |
spellingShingle |
Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean Sichel,Susanna Eleonora Equatorial Atlantic Ocean Saint Paul Fracture Zone abyssal mantle Re-Os isotope system cold mantle fossil subducted slab |
title_short |
Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean |
title_full |
Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean |
title_fullStr |
Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean |
title_full_unstemmed |
Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean |
title_sort |
Geophysical and geochemical evidence for cold upper mantle beneath the Equatorial Atlantic Ocean |
author |
Sichel,Susanna Eleonora |
author_facet |
Sichel,Susanna Eleonora Esperança,Sonia Motoki,Akihisa Maia,Marcia Horan,Mary F. Szatmari,Peter Alves,Eliane da Costa Mello,Sidney L.M. |
author_role |
author |
author2 |
Esperança,Sonia Motoki,Akihisa Maia,Marcia Horan,Mary F. Szatmari,Peter Alves,Eliane da Costa Mello,Sidney L.M. |
author2_role |
author author author author author author author |
dc.contributor.author.fl_str_mv |
Sichel,Susanna Eleonora Esperança,Sonia Motoki,Akihisa Maia,Marcia Horan,Mary F. Szatmari,Peter Alves,Eliane da Costa Mello,Sidney L.M. |
dc.subject.por.fl_str_mv |
Equatorial Atlantic Ocean Saint Paul Fracture Zone abyssal mantle Re-Os isotope system cold mantle fossil subducted slab |
topic |
Equatorial Atlantic Ocean Saint Paul Fracture Zone abyssal mantle Re-Os isotope system cold mantle fossil subducted slab |
description |
This paper presents geophysical and geochemical evidence for the possible existence of cold, subducted lithosphere beneath the Saint Paul Fracture Zone of the Equatorial Atlantic Ocean. The ocean floor along the fracture zone is characterized by a high percentage of abyssal peridotites. The abyssal peridotites were emplaced by tectonic uplift of the oceanic lithosphere. The top of the ridge is exposed at Saint Peter and Saint Paul islets. The Os isotopic composition of these abyssal peridotites indicate the presence of old depleted mantle material in this region with Re-depletion model ages (T RD) from 0.32 to 1.1Ga. Melt inclusions in plagioclase phenocrysts of the MORB close to this location have boninitic composition, suggesting that some basalts originated from low-degree mantle melting. The global tomography models show fast seismic velocities in the upper and lower mantle of the Equatorial Atlantic Ocean, consistent with the presence of cold subducted lithosphere. The range of Re-depletion model ages are consistent with paleo-reconstructions of plate motion, suggesting that the fossil subducted slab was formed during the closure of both the Iapetus and the Rheic oceans. |
publishDate |
2008 |
dc.date.none.fl_str_mv |
2008-03-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-261X2008000100006 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-261X2008000100006 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0102-261X2008000100006 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Geofísica |
publisher.none.fl_str_mv |
Sociedade Brasileira de Geofísica |
dc.source.none.fl_str_mv |
Revista Brasileira de Geofísica v.26 n.1 2008 reponame:Revista Brasileira de Geofísica (Online) instname:Sociedade Brasileira de Geofísica (SBG) instacron:SBG |
instname_str |
Sociedade Brasileira de Geofísica (SBG) |
instacron_str |
SBG |
institution |
SBG |
reponame_str |
Revista Brasileira de Geofísica (Online) |
collection |
Revista Brasileira de Geofísica (Online) |
repository.name.fl_str_mv |
Revista Brasileira de Geofísica (Online) - Sociedade Brasileira de Geofísica (SBG) |
repository.mail.fl_str_mv |
||sbgf@sbgf.org.br |
_version_ |
1754820936896348160 |