Significance of graphite inclusion occurrence in the minerals of the San Miguel skarn for the Palaeoproterozoic basement of Tandilia Belt (Argentina) and for the Río de la Plata Craton

cic.institucionOrigen Instituto de Recursos Minerales (INREMI) es
cic.isFulltext true es
cic.isPeerReviewed true es
cic.lugarDesarrollo Universidad Nacional de La Plata es
cic.lugarDesarrollo Consejo Nacional de Investigaciones Científicas y Técnicas es
cic.lugarDesarrollo YPF Tecnología es
cic.lugarDesarrollo Universidad de Salamanca es
cic.lugarDesarrollo University of Pernambuco es
cic.version info:eu-repo/semantics/publishedVersion es 2019-05-16T12:06:16Z 2019-05-16T12:06:16Z
dc.title Significance of graphite inclusion occurrence in the minerals of the San Miguel skarn for the Palaeoproterozoic basement of Tandilia Belt (Argentina) and for the Río de la Plata Craton en
dc.type Artículo es
dcterms.abstract Graphite in Archaean-Palaeoproterozoic rocks has been a subject of interest since it could represent an evidence of early life on Earth. In the Palaeoproterozoic basement of the Tandilia Belt, graphite was found both in fluid inclusions (FI) hosted in the San Miguel skarn calc-silicate minerals, and as solid inclusions in calcite crystals from the protolithic marble (a13C enriched carbonate from the “Lomagundi-Jatuli event”). FI microthermometry and oxygen stable isotope ratios indicated the skarn minerals formation within the range of 630–650 °C (at ∼5 kbars) and ∼642–654 °C, respectively. Also, the characterisation of the metasomatic fluid (of a low salinity< 7 wt% NaCl eq. NaCleH2O/NaCleKCleH2O aqueous system) pointed out that the zonal crystallisation pattern shown by the skarn minerals (wollastonite-vesuvianite, grossular-diopside-calcite and diopside-calcite zones in the exoskarn, and grossular-diopside and diopside-calcic plagioclase zones in the endoskarn) responds to the increase of the involved cation activity gradients (Ca2+-Si4+-Mg2+-Fe2+/3+-Al3+) and not to significant changes in the temperature or concentration of CO2 in the system. Variation in the crystallinity degree of the graphite hosted in the skarn minerals and in marble calcite, shown by Raman spectroscopy, would indicate that the graphite could have been formed from the ripening of organic matter present in the sedimentary rocks during the metamorphic-metasomatic event (Transamazonian Orogeny). In this sense, the increase of the organic carbon productivity in the oceans during the Palaeoproterozoic, represented by the “Lomagundi-Jatuli event”, would support this graphite origin and also the possible existence of a marine sedimentary basin in the previous stages of the Río de la Plata amalgamation (Siderian-Rhyacian), in the San Miguel area of the Tandilia Belt. en Lajoinie, María Florencia es Ballivián Justiniano, Carlos A. es Salvioli, Melisa es Ruiz, R. es Recio, C. es Sial, A. N. es Etcheverry, Ricardo O. es Curci, Marcela V. es Calf, H.G. de la es Lanfranchini, Mabel Elena es
dcterms.extent p. 118-139 es
dcterms.identifier.other doi:10.1016/j.jsames.2018.11.008 es
dcterms.identifier.url Recurso online es
dcterms.isPartOf.issue vol. 89 es
dcterms.isPartOf.series Journal of South American Earth Sciences es
dcterms.issued 2019-01
dcterms.language Inglés es
dcterms.license Attribution-NonCommercial-ShareAlike 4.0 International (BY-NC-SA 4.0) es
dcterms.spatial Río de la Plata (Argentina) es
dcterms.subject Lomagundi-Jatuli event en
dcterms.subject Metasomatism en
dcterms.subject Fluid inclusions en
dcterms.subject Raman spectroscopy en
dcterms.subject Syngenetic graphite en
dcterms.subject.materia Geología es
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