Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C)
Carbonate-silicate rocks of unclear origin have been observed in granulites of the Porya Guba of the Lapland-Kolvitsa Belt within the Fennoscandinavian Shield. The present work aims to reconstruct possible protoliths and conditions of metamorphic transformation of these rocks based on oxygen and car...
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| Format: | Article |
| Language: | English |
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Saint-Petersburg Mining University
2024-02-01
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| Series: | Записки Горного института |
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| Online Access: | https://pmi.spmi.ru/pmi/article/view/16150?setLocale=en_US |
| _version_ | 1797279045773164544 |
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| author | Dmitrii P. Krylov Ekaterina V. Klimova |
| author_facet | Dmitrii P. Krylov Ekaterina V. Klimova |
| author_sort | Dmitrii P. Krylov |
| collection | DOAJ |
| description | Carbonate-silicate rocks of unclear origin have been observed in granulites of the Porya Guba of the Lapland-Kolvitsa Belt within the Fennoscandinavian Shield. The present work aims to reconstruct possible protoliths and conditions of metamorphic transformation of these rocks based on oxygen and carbon isotopic ratios combined with phase equilibria modeling. Isotope analysis and lithochemical reconstructions suggest that carbonate-silicate rocks of the Porya Guba represent metamorphosed sediments (possibly marls) with the isotopic composition corresponding to the Precambrian diagenetically transformed carbonates (δ18O ≈ 17.9 ‰, SMOW and δ13C ≈ –3.4 ‰, PDB). The chemical composition varies depending on the balance among the carbonate, clay, and clastic components. Significant changes of the isotopic composition during metamorphism are caused by decomposition reactions of primary carbonates (dolomite, siderite, and ankerite) producing CO2 followed by degassing. These reactions are accompanied by δ18O and δ13C decrease of calcite in isotopic equilibrium with CO2 down to 15 ‰ (SMOW) and –6 ‰ (PDB), respectively. The isotopic composition is buffered by local reactions within individual rock varieties, thus excluding any pronounced influence of magmatic and/or metasomatic processes. |
| first_indexed | 2024-03-07T16:17:45Z |
| format | Article |
| id | doaj.art-4f9355627b074d729254ac67b1f2c41a |
| institution | Directory Open Access Journal |
| issn | 2411-3336 2541-9404 |
| language | English |
| last_indexed | 2024-03-07T16:17:45Z |
| publishDate | 2024-02-01 |
| publisher | Saint-Petersburg Mining University |
| record_format | Article |
| series | Записки Горного института |
| spelling | doaj.art-4f9355627b074d729254ac67b1f2c41a2024-03-04T10:04:53ZengSaint-Petersburg Mining UniversityЗаписки Горного института2411-33362541-94042024-02-0126531516150Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C)Dmitrii P. Krylov0https://orcid.org/0000-0001-6654-8659Ekaterina V. Klimova1https://orcid.org/0000-0002-9771-9518Institute of Precambrian Geology and Geochronology RASInstitute of Precambrian Geology and Geochronology RASCarbonate-silicate rocks of unclear origin have been observed in granulites of the Porya Guba of the Lapland-Kolvitsa Belt within the Fennoscandinavian Shield. The present work aims to reconstruct possible protoliths and conditions of metamorphic transformation of these rocks based on oxygen and carbon isotopic ratios combined with phase equilibria modeling. Isotope analysis and lithochemical reconstructions suggest that carbonate-silicate rocks of the Porya Guba represent metamorphosed sediments (possibly marls) with the isotopic composition corresponding to the Precambrian diagenetically transformed carbonates (δ18O ≈ 17.9 ‰, SMOW and δ13C ≈ –3.4 ‰, PDB). The chemical composition varies depending on the balance among the carbonate, clay, and clastic components. Significant changes of the isotopic composition during metamorphism are caused by decomposition reactions of primary carbonates (dolomite, siderite, and ankerite) producing CO2 followed by degassing. These reactions are accompanied by δ18O and δ13C decrease of calcite in isotopic equilibrium with CO2 down to 15 ‰ (SMOW) and –6 ‰ (PDB), respectively. The isotopic composition is buffered by local reactions within individual rock varieties, thus excluding any pronounced influence of magmatic and/or metasomatic processes.https://pmi.spmi.ru/pmi/article/view/16150?setLocale=en_UScarbonate-silicate rocksstable isotopesmetamorphisminorganic carbon cycleisotope fractionationrayleigh distillation |
| spellingShingle | Dmitrii P. Krylov Ekaterina V. Klimova Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C) Записки Горного института carbonate-silicate rocks stable isotopes metamorphism inorganic carbon cycle isotope fractionation rayleigh distillation |
| title | Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C) |
| title_full | Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C) |
| title_fullStr | Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C) |
| title_full_unstemmed | Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C) |
| title_short | Origin of carbonate-silicate rocks of the Porya Guba (the Lapland-Kolvitsa Granulite Belt) revealed by stable isotope analysis (δ18O, δ13C) |
| title_sort | origin of carbonate silicate rocks of the porya guba the lapland kolvitsa granulite belt revealed by stable isotope analysis δ18o δ13c |
| topic | carbonate-silicate rocks stable isotopes metamorphism inorganic carbon cycle isotope fractionation rayleigh distillation |
| url | https://pmi.spmi.ru/pmi/article/view/16150?setLocale=en_US |
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