Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study

Autores
Sola, Alfonso Manuel; Becchio, Raul Alberto; Pimentel, Márcio M.
Año de publicación
2013
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
In Sierra de Molinos, Eastern Cordillera, NW Argentina the relationship between different components of an anatectic system developed in high temperature and low pressure conditions (800 °C and 4_6 kbar) can be observed. This allows the direct insight on the origin of migmatites and granites by anatexis of psammo?pelitic metasedimentary rocks. Four principal rock types have been recognized in Sierra de Molinos 1) metasedimentary rocks, assigned to the Puncoviscana Formation, 2) metatexite migmatites, 3) diatexite migmatites and 4) anatectic granitoids including: leucogranites, trondhjemites and pegmatite/aplitic dykes. The metamorphic grade increases from phyllites and schists at sub-greenschist and greenschist facies in the west, to upper amphibolite facies migmatites in the east. The mineral assemblages indicate a progressive increase in temperature without a significant change in pressure. The ages obtained for granitoids and migmatites are identical within analytical errors and indicate that the metamorphic peak and anatectic granite generation occurred at ca. 470 Ma. We use petrological and geochemical variations to investigate the formation of granite magma from migmatites that derived from metasedimentary protoliths. This provides evidence of the processes that occur during the evolution (melting, segregation and crystallization stages) of partially molten terranes, for which particular components: protolith, residuum and melt fractions are identified. Mass balance calculations are used to estimate the degree of partial melting and the degree of melt extraction in migmatites. Petrological and compositional data suggest that migmatites from this region are the result of open system processes and that fluid-absent melting played a major role in the formation of migmatites and leucogranites. The geochemical evidence suggests that the compositional variation within the anatectic rocks from Molinos can be understood as a result of 1) variable degrees of melt?residuum separation and 2) fractional crystallization of the anatectic melt. Compared to the protolith, most of the migmatites have melt-depleted compositions (up to 0.25 of melt extraction). In the same fashion most of the leucosomes represent cumulate products of fractional crystallization. This means that they have lost some liquid of evolved composition and represent evidence of the melt extraction pathways and linkage to the magma ascent conduits.
Fil: Sola, Alfonso Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Salta. Instituto de Investigaciones En Energía No Convencional; Argentina. Universidad Nacional de Salta; Argentina
Fil: Becchio, Raul Alberto. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Salta. Instituto de Investigaciones En Energía No Convencional; Argentina
Fil: Pimentel, Márcio M.. Universidade Do Brasilia. Instituto de Geociencias;
Materia
Migmatites
Leucogranites
Geochemistry
Partial Melting
Nw Argentina
Famatinian Belt
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:11336/1472

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spelling Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical studySola, Alfonso ManuelBecchio, Raul AlbertoPimentel, Márcio M.MigmatitesLeucogranitesGeochemistryPartial MeltingNw ArgentinaFamatinian Belthttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1In Sierra de Molinos, Eastern Cordillera, NW Argentina the relationship between different components of an anatectic system developed in high temperature and low pressure conditions (800 °C and 4_6 kbar) can be observed. This allows the direct insight on the origin of migmatites and granites by anatexis of psammo?pelitic metasedimentary rocks. Four principal rock types have been recognized in Sierra de Molinos 1) metasedimentary rocks, assigned to the Puncoviscana Formation, 2) metatexite migmatites, 3) diatexite migmatites and 4) anatectic granitoids including: leucogranites, trondhjemites and pegmatite/aplitic dykes. The metamorphic grade increases from phyllites and schists at sub-greenschist and greenschist facies in the west, to upper amphibolite facies migmatites in the east. The mineral assemblages indicate a progressive increase in temperature without a significant change in pressure. The ages obtained for granitoids and migmatites are identical within analytical errors and indicate that the metamorphic peak and anatectic granite generation occurred at ca. 470 Ma. We use petrological and geochemical variations to investigate the formation of granite magma from migmatites that derived from metasedimentary protoliths. This provides evidence of the processes that occur during the evolution (melting, segregation and crystallization stages) of partially molten terranes, for which particular components: protolith, residuum and melt fractions are identified. Mass balance calculations are used to estimate the degree of partial melting and the degree of melt extraction in migmatites. Petrological and compositional data suggest that migmatites from this region are the result of open system processes and that fluid-absent melting played a major role in the formation of migmatites and leucogranites. The geochemical evidence suggests that the compositional variation within the anatectic rocks from Molinos can be understood as a result of 1) variable degrees of melt?residuum separation and 2) fractional crystallization of the anatectic melt. Compared to the protolith, most of the migmatites have melt-depleted compositions (up to 0.25 of melt extraction). In the same fashion most of the leucosomes represent cumulate products of fractional crystallization. This means that they have lost some liquid of evolved composition and represent evidence of the melt extraction pathways and linkage to the magma ascent conduits.Fil: Sola, Alfonso Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Salta. Instituto de Investigaciones En Energía No Convencional; Argentina. Universidad Nacional de Salta; ArgentinaFil: Becchio, Raul Alberto. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Salta. Instituto de Investigaciones En Energía No Convencional; ArgentinaFil: Pimentel, Márcio M.. Universidade Do Brasilia. Instituto de Geociencias;Elsevier Science Bv2013-09info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/1472Sola, Alfonso Manuel; Becchio, Raul Alberto; Pimentel, Márcio M.; Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study; Elsevier Science Bv; Lithos; 177; 9-2013; 470-4910024-4937enginfo:eu-repo/semantics/altIdentifier/doi/10.1016/j.lithos.2013.07.025info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:54:33Zoai:ri.conicet.gov.ar:11336/1472instacron: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:34982025-09-29 09:54:33.382CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study
title Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study
spellingShingle Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study
Sola, Alfonso Manuel
Migmatites
Leucogranites
Geochemistry
Partial Melting
Nw Argentina
Famatinian Belt
title_short Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study
title_full Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study
title_fullStr Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study
title_full_unstemmed Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study
title_sort Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study
dc.creator.none.fl_str_mv Sola, Alfonso Manuel
Becchio, Raul Alberto
Pimentel, Márcio M.
author Sola, Alfonso Manuel
author_facet Sola, Alfonso Manuel
Becchio, Raul Alberto
Pimentel, Márcio M.
author_role author
author2 Becchio, Raul Alberto
Pimentel, Márcio M.
author2_role author
author
dc.subject.none.fl_str_mv Migmatites
Leucogranites
Geochemistry
Partial Melting
Nw Argentina
Famatinian Belt
topic Migmatites
Leucogranites
Geochemistry
Partial Melting
Nw Argentina
Famatinian Belt
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv In Sierra de Molinos, Eastern Cordillera, NW Argentina the relationship between different components of an anatectic system developed in high temperature and low pressure conditions (800 °C and 4_6 kbar) can be observed. This allows the direct insight on the origin of migmatites and granites by anatexis of psammo?pelitic metasedimentary rocks. Four principal rock types have been recognized in Sierra de Molinos 1) metasedimentary rocks, assigned to the Puncoviscana Formation, 2) metatexite migmatites, 3) diatexite migmatites and 4) anatectic granitoids including: leucogranites, trondhjemites and pegmatite/aplitic dykes. The metamorphic grade increases from phyllites and schists at sub-greenschist and greenschist facies in the west, to upper amphibolite facies migmatites in the east. The mineral assemblages indicate a progressive increase in temperature without a significant change in pressure. The ages obtained for granitoids and migmatites are identical within analytical errors and indicate that the metamorphic peak and anatectic granite generation occurred at ca. 470 Ma. We use petrological and geochemical variations to investigate the formation of granite magma from migmatites that derived from metasedimentary protoliths. This provides evidence of the processes that occur during the evolution (melting, segregation and crystallization stages) of partially molten terranes, for which particular components: protolith, residuum and melt fractions are identified. Mass balance calculations are used to estimate the degree of partial melting and the degree of melt extraction in migmatites. Petrological and compositional data suggest that migmatites from this region are the result of open system processes and that fluid-absent melting played a major role in the formation of migmatites and leucogranites. The geochemical evidence suggests that the compositional variation within the anatectic rocks from Molinos can be understood as a result of 1) variable degrees of melt?residuum separation and 2) fractional crystallization of the anatectic melt. Compared to the protolith, most of the migmatites have melt-depleted compositions (up to 0.25 of melt extraction). In the same fashion most of the leucosomes represent cumulate products of fractional crystallization. This means that they have lost some liquid of evolved composition and represent evidence of the melt extraction pathways and linkage to the magma ascent conduits.
Fil: Sola, Alfonso Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Salta. Instituto de Investigaciones En Energía No Convencional; Argentina. Universidad Nacional de Salta; Argentina
Fil: Becchio, Raul Alberto. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Salta. Instituto de Investigaciones En Energía No Convencional; Argentina
Fil: Pimentel, Márcio M.. Universidade Do Brasilia. Instituto de Geociencias;
description In Sierra de Molinos, Eastern Cordillera, NW Argentina the relationship between different components of an anatectic system developed in high temperature and low pressure conditions (800 °C and 4_6 kbar) can be observed. This allows the direct insight on the origin of migmatites and granites by anatexis of psammo?pelitic metasedimentary rocks. Four principal rock types have been recognized in Sierra de Molinos 1) metasedimentary rocks, assigned to the Puncoviscana Formation, 2) metatexite migmatites, 3) diatexite migmatites and 4) anatectic granitoids including: leucogranites, trondhjemites and pegmatite/aplitic dykes. The metamorphic grade increases from phyllites and schists at sub-greenschist and greenschist facies in the west, to upper amphibolite facies migmatites in the east. The mineral assemblages indicate a progressive increase in temperature without a significant change in pressure. The ages obtained for granitoids and migmatites are identical within analytical errors and indicate that the metamorphic peak and anatectic granite generation occurred at ca. 470 Ma. We use petrological and geochemical variations to investigate the formation of granite magma from migmatites that derived from metasedimentary protoliths. This provides evidence of the processes that occur during the evolution (melting, segregation and crystallization stages) of partially molten terranes, for which particular components: protolith, residuum and melt fractions are identified. Mass balance calculations are used to estimate the degree of partial melting and the degree of melt extraction in migmatites. Petrological and compositional data suggest that migmatites from this region are the result of open system processes and that fluid-absent melting played a major role in the formation of migmatites and leucogranites. The geochemical evidence suggests that the compositional variation within the anatectic rocks from Molinos can be understood as a result of 1) variable degrees of melt?residuum separation and 2) fractional crystallization of the anatectic melt. Compared to the protolith, most of the migmatites have melt-depleted compositions (up to 0.25 of melt extraction). In the same fashion most of the leucosomes represent cumulate products of fractional crystallization. This means that they have lost some liquid of evolved composition and represent evidence of the melt extraction pathways and linkage to the magma ascent conduits.
publishDate 2013
dc.date.none.fl_str_mv 2013-09
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/11336/1472
Sola, Alfonso Manuel; Becchio, Raul Alberto; Pimentel, Márcio M.; Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study; Elsevier Science Bv; Lithos; 177; 9-2013; 470-491
0024-4937
url http://hdl.handle.net/11336/1472
identifier_str_mv Sola, Alfonso Manuel; Becchio, Raul Alberto; Pimentel, Márcio M.; Petrogenesis of migmatites and leucogranites from Sierra de Molinos, Salta, Northwest Argentina: A petrologic and geochemical study; Elsevier Science Bv; Lithos; 177; 9-2013; 470-491
0024-4937
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1016/j.lithos.2013.07.025
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 Bv
publisher.none.fl_str_mv Elsevier Science Bv
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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