Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle

Autores
Rivalenti, Giorgio; Mazzucchelli, Maurizio; Zanetti, Alberto; Vannucci, Riccardo; Bollinger, Claire; Hémond, Christophe; Bertotto, Gustavo Walter
Año de publicación
2007
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The alkali basalts of the Cerro de los Chenques quaternary backarc volcano (200 km E of the volcanic arc) carry to the surface abundant spinel-facies mantle xenoliths (lherzolites, harzburgites and dunites). The clinopyroxene geochemistry indicates that the pristine mantle was a lherzolite with Depleted Mantle (DM) composition, recording either melting episodes triggered by infiltration of a metasomatic agent or only enrichment of highly incompatible elements in those sectors where percolation occurred under decreasing fluid volume. Metasomatism was operated by a fluid originated in garnet-bearing assemblages that induced olivine and clinopyroxene dissolution, variations in the Sr and Nd isotopic signatures (i.e. pre-metasomatic mantle: 87Sr/86Sr = 0.702712 and 143Nd/144Nd = 0.513495; xenoliths recording the highest metasomatism: 87Sr/86Sr = 0.704234 and143Nd/144Nd = 0.512870), and increase in LILE and LREE, but not in Nb and Ti. The resulting geochemical characteristics are similar to those observed in arc magmas and are consistent with the signatures of sediments and basalts forming the upper part of the subducted Nazca plate. Evidence for element fractionation operated by infiltration of the host alkali basalts and related reactive porous-flow processes are lacking or weak. The granoblastic texture of the xenoliths, bearing no evidence of deformation, rules out the hypothesis that the Chenques mantle formed in the subarc and was transported 200 km to the east by reverse corner flow. Alternatively, it is suggested that the slab components were released as supercritical fluids beneath Chenques (at ∼ 6 GPa) by phengite breakdown. Fluids flowed through, and reacted with, the hidden garnet-facies mantle and reached the observed spinel-facies level. Reactions in the hidden mantle region led the supercritical fluid to increase (La/Sm)N, Th, U, Nb, Pb and Sr while decreasing its initial (Sm/Yb)N and Ti.
Fil: Rivalenti, Giorgio. Università di Modena e Reggio Emilia; Italia
Fil: Mazzucchelli, Maurizio. Università di Modena e Reggio Emilia; Italia
Fil: Zanetti, Alberto. Istituto di Geoscienze e Georisorse; Italia
Fil: Vannucci, Riccardo. Istituto di Geoscienze e Georisorse; Italia. Università di Pavia; Italia
Fil: Bollinger, Claire. Centre National de la Recherche Scientifique; Francia
Fil: Hémond, Christophe. Centre National de la Recherche Scientifique; Francia
Fil: Bertotto, Gustavo Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina
Materia
Backarc Mantle Lithosphere
Nazca Plate
Patagonia
Subducted Slab Fluids
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/81741
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/81741
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantleRivalenti, GiorgioMazzucchelli, MaurizioZanetti, AlbertoVannucci, RiccardoBollinger, ClaireHémond, ChristopheBertotto, Gustavo WalterBackarc Mantle LithosphereNazca PlatePatagoniaSubducted Slab Fluidshttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1The alkali basalts of the Cerro de los Chenques quaternary backarc volcano (200 km E of the volcanic arc) carry to the surface abundant spinel-facies mantle xenoliths (lherzolites, harzburgites and dunites). The clinopyroxene geochemistry indicates that the pristine mantle was a lherzolite with Depleted Mantle (DM) composition, recording either melting episodes triggered by infiltration of a metasomatic agent or only enrichment of highly incompatible elements in those sectors where percolation occurred under decreasing fluid volume. Metasomatism was operated by a fluid originated in garnet-bearing assemblages that induced olivine and clinopyroxene dissolution, variations in the Sr and Nd isotopic signatures (i.e. pre-metasomatic mantle: 87Sr/86Sr = 0.702712 and 143Nd/144Nd = 0.513495; xenoliths recording the highest metasomatism: 87Sr/86Sr = 0.704234 and143Nd/144Nd = 0.512870), and increase in LILE and LREE, but not in Nb and Ti. The resulting geochemical characteristics are similar to those observed in arc magmas and are consistent with the signatures of sediments and basalts forming the upper part of the subducted Nazca plate. Evidence for element fractionation operated by infiltration of the host alkali basalts and related reactive porous-flow processes are lacking or weak. The granoblastic texture of the xenoliths, bearing no evidence of deformation, rules out the hypothesis that the Chenques mantle formed in the subarc and was transported 200 km to the east by reverse corner flow. Alternatively, it is suggested that the slab components were released as supercritical fluids beneath Chenques (at ∼ 6 GPa) by phengite breakdown. Fluids flowed through, and reacted with, the hidden garnet-facies mantle and reached the observed spinel-facies level. Reactions in the hidden mantle region led the supercritical fluid to increase (La/Sm)N, Th, U, Nb, Pb and Sr while decreasing its initial (Sm/Yb)N and Ti.Fil: Rivalenti, Giorgio. Università di Modena e Reggio Emilia; ItaliaFil: Mazzucchelli, Maurizio. Università di Modena e Reggio Emilia; ItaliaFil: Zanetti, Alberto. Istituto di Geoscienze e Georisorse; ItaliaFil: Vannucci, Riccardo. Istituto di Geoscienze e Georisorse; Italia. Università di Pavia; ItaliaFil: Bollinger, Claire. Centre National de la Recherche Scientifique; FranciaFil: Hémond, Christophe. Centre National de la Recherche Scientifique; FranciaFil: Bertotto, Gustavo Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaElsevier Science2007-11info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/81741Rivalenti, Giorgio; Mazzucchelli, Maurizio; Zanetti, Alberto; Vannucci, Riccardo; Bollinger, Claire; et al.; Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle; Elsevier Science; Lithos; 99; 1-2; 11-2007; 45-670024-4937CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/pii/S0024493707001065info:eu-repo/semantics/altIdentifier/doi/10.1016/j.lithos.2007.05.012info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-10T13:00:12Zoai:ri.conicet.gov.ar:11336/81741instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-10 13:00:12.965CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle
title Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle
spellingShingle Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle
Rivalenti, Giorgio
Backarc Mantle Lithosphere
Nazca Plate
Patagonia
Subducted Slab Fluids
title_short Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle
title_full Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle
title_fullStr Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle
title_full_unstemmed Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle
title_sort Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle
dc.creator.none.fl_str_mv Rivalenti, Giorgio
Mazzucchelli, Maurizio
Zanetti, Alberto
Vannucci, Riccardo
Bollinger, Claire
Hémond, Christophe
Bertotto, Gustavo Walter
author Rivalenti, Giorgio
author_facet Rivalenti, Giorgio
Mazzucchelli, Maurizio
Zanetti, Alberto
Vannucci, Riccardo
Bollinger, Claire
Hémond, Christophe
Bertotto, Gustavo Walter
author_role author
author2 Mazzucchelli, Maurizio
Zanetti, Alberto
Vannucci, Riccardo
Bollinger, Claire
Hémond, Christophe
Bertotto, Gustavo Walter
author2_role author
author
author
author
author
author
dc.subject.none.fl_str_mv Backarc Mantle Lithosphere
Nazca Plate
Patagonia
Subducted Slab Fluids
topic Backarc Mantle Lithosphere
Nazca Plate
Patagonia
Subducted Slab Fluids
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv The alkali basalts of the Cerro de los Chenques quaternary backarc volcano (200 km E of the volcanic arc) carry to the surface abundant spinel-facies mantle xenoliths (lherzolites, harzburgites and dunites). The clinopyroxene geochemistry indicates that the pristine mantle was a lherzolite with Depleted Mantle (DM) composition, recording either melting episodes triggered by infiltration of a metasomatic agent or only enrichment of highly incompatible elements in those sectors where percolation occurred under decreasing fluid volume. Metasomatism was operated by a fluid originated in garnet-bearing assemblages that induced olivine and clinopyroxene dissolution, variations in the Sr and Nd isotopic signatures (i.e. pre-metasomatic mantle: 87Sr/86Sr = 0.702712 and 143Nd/144Nd = 0.513495; xenoliths recording the highest metasomatism: 87Sr/86Sr = 0.704234 and143Nd/144Nd = 0.512870), and increase in LILE and LREE, but not in Nb and Ti. The resulting geochemical characteristics are similar to those observed in arc magmas and are consistent with the signatures of sediments and basalts forming the upper part of the subducted Nazca plate. Evidence for element fractionation operated by infiltration of the host alkali basalts and related reactive porous-flow processes are lacking or weak. The granoblastic texture of the xenoliths, bearing no evidence of deformation, rules out the hypothesis that the Chenques mantle formed in the subarc and was transported 200 km to the east by reverse corner flow. Alternatively, it is suggested that the slab components were released as supercritical fluids beneath Chenques (at ∼ 6 GPa) by phengite breakdown. Fluids flowed through, and reacted with, the hidden garnet-facies mantle and reached the observed spinel-facies level. Reactions in the hidden mantle region led the supercritical fluid to increase (La/Sm)N, Th, U, Nb, Pb and Sr while decreasing its initial (Sm/Yb)N and Ti.
Fil: Rivalenti, Giorgio. Università di Modena e Reggio Emilia; Italia
Fil: Mazzucchelli, Maurizio. Università di Modena e Reggio Emilia; Italia
Fil: Zanetti, Alberto. Istituto di Geoscienze e Georisorse; Italia
Fil: Vannucci, Riccardo. Istituto di Geoscienze e Georisorse; Italia. Università di Pavia; Italia
Fil: Bollinger, Claire. Centre National de la Recherche Scientifique; Francia
Fil: Hémond, Christophe. Centre National de la Recherche Scientifique; Francia
Fil: Bertotto, Gustavo Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina
description The alkali basalts of the Cerro de los Chenques quaternary backarc volcano (200 km E of the volcanic arc) carry to the surface abundant spinel-facies mantle xenoliths (lherzolites, harzburgites and dunites). The clinopyroxene geochemistry indicates that the pristine mantle was a lherzolite with Depleted Mantle (DM) composition, recording either melting episodes triggered by infiltration of a metasomatic agent or only enrichment of highly incompatible elements in those sectors where percolation occurred under decreasing fluid volume. Metasomatism was operated by a fluid originated in garnet-bearing assemblages that induced olivine and clinopyroxene dissolution, variations in the Sr and Nd isotopic signatures (i.e. pre-metasomatic mantle: 87Sr/86Sr = 0.702712 and 143Nd/144Nd = 0.513495; xenoliths recording the highest metasomatism: 87Sr/86Sr = 0.704234 and143Nd/144Nd = 0.512870), and increase in LILE and LREE, but not in Nb and Ti. The resulting geochemical characteristics are similar to those observed in arc magmas and are consistent with the signatures of sediments and basalts forming the upper part of the subducted Nazca plate. Evidence for element fractionation operated by infiltration of the host alkali basalts and related reactive porous-flow processes are lacking or weak. The granoblastic texture of the xenoliths, bearing no evidence of deformation, rules out the hypothesis that the Chenques mantle formed in the subarc and was transported 200 km to the east by reverse corner flow. Alternatively, it is suggested that the slab components were released as supercritical fluids beneath Chenques (at ∼ 6 GPa) by phengite breakdown. Fluids flowed through, and reacted with, the hidden garnet-facies mantle and reached the observed spinel-facies level. Reactions in the hidden mantle region led the supercritical fluid to increase (La/Sm)N, Th, U, Nb, Pb and Sr while decreasing its initial (Sm/Yb)N and Ti.
publishDate 2007
dc.date.none.fl_str_mv 2007-11
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/81741
Rivalenti, Giorgio; Mazzucchelli, Maurizio; Zanetti, Alberto; Vannucci, Riccardo; Bollinger, Claire; et al.; Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle; Elsevier Science; Lithos; 99; 1-2; 11-2007; 45-67
0024-4937
CONICET Digital
CONICET
url http://hdl.handle.net/11336/81741
identifier_str_mv Rivalenti, Giorgio; Mazzucchelli, Maurizio; Zanetti, Alberto; Vannucci, Riccardo; Bollinger, Claire; et al.; Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle; Elsevier Science; Lithos; 99; 1-2; 11-2007; 45-67
0024-4937
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/pii/S0024493707001065
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.lithos.2007.05.012
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Elsevier Science
publisher.none.fl_str_mv Elsevier Science
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 12.993085

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