The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif

Highly deformed banded phengite-biotite metagranite from the Snieznik dome in the Bohemian Massif has been modified locally to have stromatic, schlieren or nebulitic textures typical of migmatites. This occurred mostly along subvertical deformation zones at eclogite-facies conditions, at a scale of...

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Autores: Stípská, Pavla, Hasalová Pavlína, Powell, P., Závada, Prokop, Schulmann, Karel, Racek, Martin, Aguilar Gil, Carmen María, Chopin, Francis
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2019
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:2445/181672
Acceso en línea:https://hdl.handle.net/2445/181672
Access Level:acceso abierto
Palabra clave:Petrologia
Granit
Petrology
Granite
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spelling The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia MassifStípská, PavlaHasalová PavlínaPowell, P.Závada, ProkopSchulmann, KarelRacek, MartinAguilar Gil, Carmen MaríaChopin, FrancisPetrologiaGranitPetrologyGraniteHighly deformed banded phengite-biotite metagranite from the Snieznik dome in the Bohemian Massif has been modified locally to have stromatic, schlieren or nebulitic textures typical of migmatites. This occurred mostly along subvertical deformation zones at eclogite-facies conditions, at a scale of several centimetres to several metres, mostly parallel to the foliation. The transition from banded to migmatite types of orthogneiss is marked by an increase in the amount of phases interstitial along grain boundaries in the dynamically recrystallized monomineralic feldspar and quartz aggregates, and by increasing consumption of recrystallized K-feldspar grains by fine-grained plagioclase and quartz, as well as myrmekite (intergrowth of PlQz). The new minerals are in textural equilibrium with phengite. The myrmekite, quartz and feldspars can be coarse-grained (grain size 05cm). These features are considered to be the result of grain-scale melt infiltration that caused dissolution-reprecipitation along grain boundaries in the presence of phengite. The infiltration was pervasive at the grain scale, but localized at hand-specimen to outcrop scales. All the rock types have the same mineral assemblage of Grt+Ph+Bt+Ttn+Kfs+Pl+Qz+Rt+Ilm; they have similar garnet, phengite and biotite compositions, and based on mineral equilibria modelling we infer equilibration at a pressure of 15-17GPa and a temperature of 690-740C. Because the rocks are inferred to be H2O-undersaturated and above the temperature conditions of the wet solidus, infiltration must have involved a hydrous melt, as opposed to an H2O fluid. Stability of melt-bearing mineral assemblages and mineral compositions are almost independent of the melt proportion in the system, thus explaining the identical assemblage and mineral compositions observed in all the migmatite types. This precludes the estimation of the amount of melt infiltrated. Migmatite textures, however, suggest that variable degrees of melt-rock interaction occurred, being low in the banded migmatite types and higher in the nebulitic and schlieren types. Retrograde equilibration was largely restricted to retrograde zoning in phengite, garnet and plagioclase, and crystallization of biotite around phengite and garnet, presumably in a continuous reaction consuming melt. This may have occurred down to 07-10 GPa. According to Sr-Nd isotope data, the infiltrating melt is probably derived from similar rocks, structurally beneath the observed ones. The infiltration may have facilitated exhumation of a 2 km wide structural domain from 17 to 07 GPa, within which are the subvertical deformation zones along which the infiltration occurred.Oxford University Press2021202120192021info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersion35 p.application/pdfhttps://hdl.handle.net/2445/181672Articles publicats en revistes (Mineralogia, Petrologia i Geologia Aplicada)reponame:Recercat. Dipósit de la Recerca de Catalunyainstname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)InglésVersió postprint del document publicat a: https://doi.org/10.1093/petrology/egz007Journal of Petrology, 2019, vol. 60, num. 3, p. 591-618https://doi.org/10.1093/petrology/egz007(c) Stípská, Pavla et al., 2019info:eu-repo/semantics/openAccessoai:recercat.cat:2445/1816722026-05-29T05:05:01Z
dc.title.none.fl_str_mv The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif
title The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif
spellingShingle The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif
Stípská, Pavla
Petrologia
Granit
Petrology
Granite
title_short The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif
title_full The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif
title_fullStr The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif
title_full_unstemmed The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif
title_sort The Effect of melt infiltration on metagranitic rocks: The Snieznik dome, Bohemia Massif
dc.creator.none.fl_str_mv Stípská, Pavla
Hasalová Pavlína
Powell, P.
Závada, Prokop
Schulmann, Karel
Racek, Martin
Aguilar Gil, Carmen María
Chopin, Francis
author Stípská, Pavla
author_facet Stípská, Pavla
Hasalová Pavlína
Powell, P.
Závada, Prokop
Schulmann, Karel
Racek, Martin
Aguilar Gil, Carmen María
Chopin, Francis
author_role author
author2 Hasalová Pavlína
Powell, P.
Závada, Prokop
Schulmann, Karel
Racek, Martin
Aguilar Gil, Carmen María
Chopin, Francis
author2_role author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Petrologia
Granit
Petrology
Granite
topic Petrologia
Granit
Petrology
Granite
description Highly deformed banded phengite-biotite metagranite from the Snieznik dome in the Bohemian Massif has been modified locally to have stromatic, schlieren or nebulitic textures typical of migmatites. This occurred mostly along subvertical deformation zones at eclogite-facies conditions, at a scale of several centimetres to several metres, mostly parallel to the foliation. The transition from banded to migmatite types of orthogneiss is marked by an increase in the amount of phases interstitial along grain boundaries in the dynamically recrystallized monomineralic feldspar and quartz aggregates, and by increasing consumption of recrystallized K-feldspar grains by fine-grained plagioclase and quartz, as well as myrmekite (intergrowth of PlQz). The new minerals are in textural equilibrium with phengite. The myrmekite, quartz and feldspars can be coarse-grained (grain size 05cm). These features are considered to be the result of grain-scale melt infiltration that caused dissolution-reprecipitation along grain boundaries in the presence of phengite. The infiltration was pervasive at the grain scale, but localized at hand-specimen to outcrop scales. All the rock types have the same mineral assemblage of Grt+Ph+Bt+Ttn+Kfs+Pl+Qz+Rt+Ilm; they have similar garnet, phengite and biotite compositions, and based on mineral equilibria modelling we infer equilibration at a pressure of 15-17GPa and a temperature of 690-740C. Because the rocks are inferred to be H2O-undersaturated and above the temperature conditions of the wet solidus, infiltration must have involved a hydrous melt, as opposed to an H2O fluid. Stability of melt-bearing mineral assemblages and mineral compositions are almost independent of the melt proportion in the system, thus explaining the identical assemblage and mineral compositions observed in all the migmatite types. This precludes the estimation of the amount of melt infiltrated. Migmatite textures, however, suggest that variable degrees of melt-rock interaction occurred, being low in the banded migmatite types and higher in the nebulitic and schlieren types. Retrograde equilibration was largely restricted to retrograde zoning in phengite, garnet and plagioclase, and crystallization of biotite around phengite and garnet, presumably in a continuous reaction consuming melt. This may have occurred down to 07-10 GPa. According to Sr-Nd isotope data, the infiltrating melt is probably derived from similar rocks, structurally beneath the observed ones. The infiltration may have facilitated exhumation of a 2 km wide structural domain from 17 to 07 GPa, within which are the subvertical deformation zones along which the infiltration occurred.
publishDate 2019
dc.date.none.fl_str_mv 2019
2021
2021
2021
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/181672
url https://hdl.handle.net/2445/181672
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Versió postprint del document publicat a: https://doi.org/10.1093/petrology/egz007
Journal of Petrology, 2019, vol. 60, num. 3, p. 591-618
https://doi.org/10.1093/petrology/egz007
dc.rights.none.fl_str_mv (c) Stípská, Pavla et al., 2019
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) Stípská, Pavla et al., 2019
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 35 p.
application/pdf
dc.publisher.none.fl_str_mv Oxford University Press
publisher.none.fl_str_mv Oxford University Press
dc.source.none.fl_str_mv Articles publicats en revistes (Mineralogia, Petrologia i Geologia Aplicada)
reponame:Recercat. Dipósit de la Recerca de Catalunya
instname:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
instname_str Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
reponame_str Recercat. Dipósit de la Recerca de Catalunya
collection Recercat. Dipósit de la Recerca de Catalunya
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,811543

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