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dc.contributor.author Sola, Alfonso Manuel
dc.contributor.author Hasalová, Pavlina
dc.contributor.author Ferrez Weinberg, Roberto
dc.contributor.author Suzaño, Nestor Omar
dc.contributor.author Becchio, Raul Alberto
dc.contributor.author Hongn, Fernando Daniel
dc.contributor.author Botelho, Nilson
dc.date.available 2018-04-06T20:05:31Z
dc.date.issued 2017-10
dc.identifier.citation Sola, Alfonso Manuel; Hasalová, Pavlina; Ferrez Weinberg, Roberto; Suzaño, Nestor Omar; Becchio, Raul Alberto; et al.; Low- P melting of metapelitic rocks and the role of H 2 O: Insights from phase equilibria modelling; Wiley Blackwell Publishing, Inc; Journal Of Metamorphic Geology; 00; 10-2017; 1-29
dc.identifier.issn 0263-4929
dc.identifier.uri http://hdl.handle.net/11336/41246
dc.description.abstract Water‐fluxed melting has long been thought to have a minor influence on the thermal and chemical structure of the crust. We report here on amphibolite facies metasedimentary rocks from the 490–450 Ma Famatinian Orogen, in northwest Argentina, that have undergone water‐fluxed incongruent biotite melting at relatively low temperature, which have produced and lost a significant volume of melt. The protoliths consist of the turbiditic Puncoviscana Formation (Neoproterozoic to Early Cambrian). The field area exhibits a condensed metamorphic field gradient, from greenschist to amphibolite facies suprasolidus conditions, recording a low pressure almost isobaric path, reaching peak conditions estimated at 700°C at 4 kbar. Thermodynamic modelling in the MnNCKFMASHTO system is applied to investigate melting at such low pressure as a function of water content. Calculations using a typical turbidite composition show how small amounts of added free H2O may increase significantly the melt fraction with little or no change in either the melt or residual phase compositions. They indicate negligible difference in normative An–Ab–Or proportions and ferromagnesian contents between melts derived by dehydration and water‐fluxed melts. The same is true for the content of H2O dissolved in melts, which remains constant and the melt produced is granitic whether or not aqueous fluids are present. Thus, neither the residue nor the melt composition are indicators of the presence of aqueous fluids during anatexis. Recognizing the impact of small additions of H2O to an anatectic terrane may therefore be difficult. The most significant change related to water‐fluxing is the relative proportions of minerals and melt fraction, rather than the actual mineral assemblage. The modal proportion of feldspar decreased while those of cordierite and biotite increased in the residual assemblages, as <5 mol.% of free H2O was added. The impact of this addition is to more than double the proportion of water‐undersaturated melt to 25–30 mol.%. We have also developed a simple way to estimate how much melt a residual rock has lost, if the compositional trends of the protoliths are known. In summary, we find that even though the addition of small amounts of free H2O impacts significantly on rock fertility, there is little obvious record in the field. The combined application of careful petrological investigation and thermodynamic modelling is the key to identify the influence of aqueous fluids, and exploit systems that became open not only to fluid influx but also to the extraction of melt.
dc.format application/pdf
dc.language.iso eng
dc.publisher Wiley Blackwell Publishing, Inc
dc.rights info:eu-repo/semantics/restrictedAccess
dc.rights.uri https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject FAMATINIAN OROGEN
dc.subject MIGMATITE
dc.subject NW ARGENTINA
dc.subject THERMOCALC
dc.subject.classification Geología
dc.subject.classification Ciencias de la Tierra y relacionadas con el Medio Ambiente
dc.subject.classification CIENCIAS NATURALES Y EXACTAS
dc.title Low- P melting of metapelitic rocks and the role of H 2 O: Insights from phase equilibria modelling
dc.type info:eu-repo/semantics/article
dc.type info:ar-repo/semantics/artículo
dc.type info:eu-repo/semantics/publishedVersion
dc.date.updated 2018-04-06T13:52:34Z
dc.journal.volume 00
dc.journal.pagination 1-29
dc.journal.pais Reino Unido
dc.journal.ciudad Londres
dc.description.fil Fil: Sola, Alfonso Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina
dc.description.fil Fil: Hasalová, Pavlina. Czech Geological Survey. Centre for Lithospheric Research; República Checa
dc.description.fil Fil: Ferrez Weinberg, Roberto. Monash University. School of Earth, Atmosphere and Environment; Australia
dc.description.fil Fil: Suzaño, Nestor Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina
dc.description.fil Fil: Becchio, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina
dc.description.fil Fil: Hongn, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; Argentina
dc.description.fil Fil: Botelho, Nilson. Universidade do Brasília; Brasil
dc.journal.title Journal Of Metamorphic Geology
dc.relation.alternativeid info:eu-repo/semantics/altIdentifier/url/https://onlinelibrary.wiley.com/doi/abs/10.1111/jmg.12279
dc.relation.alternativeid info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1111/jmg.12279
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info:eu-repo/semantics/restrictedAccess Excepto donde se diga explícitamente, este item se publica bajo la siguiente descripción: Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Unported (CC BY-NC-SA 2.5)