Age and metamorphic conditions of the granulites from Capral-Jegessky synclinoria, Anabar shield
The paper presents the results of the isotope, geochemical and thermobarometric study of plagio-crystalline schist containing in the Upper Anabar series of the Anabar Shield. Granulite complexes of the paleoplatforms are the most important issue in addressing the fundamental problem of the Earth...
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| Format: | Article |
| Language: | English |
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Saint-Petersburg Mining University
2018-02-01
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| Series: | Записки Горного института |
| Online Access: | https://pmi.spmi.ru/index.php/pmi/article/view/11907?setLocale=en_US |
| _version_ | 1797947209969303552 |
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| author | L. Yu. Sergeeva A. V. Berezin N. I. Gusev S. G. Skublov A. E. Mel'nik |
| author_facet | L. Yu. Sergeeva A. V. Berezin N. I. Gusev S. G. Skublov A. E. Mel'nik |
| author_sort | L. Yu. Sergeeva |
| collection | DOAJ |
| description | The paper presents the results of the isotope, geochemical and thermobarometric study of plagio-crystalline schist containing in the Upper Anabar series of the Anabar Shield. Granulite complexes of the paleoplatforms are the most important issue in addressing the fundamental problem of the Earth's crust origin and its composition. The early stages of crust formation which correspond to the deeply metamorphosed rocks of the platform basements, available for study within the shields, are of particular interest. The study of the age and metamorphic conditions of granulites by the case of the Upper Ananbar series allows specifying the stages the Anabar Shield's ancient crust formation.
Isotope-geochemical (U-Pb geochronology for zircon and Sm-Nd for garnet-amphibole-WR) and thermoba-rometric (Theriak-Domino) studies of plagio-crystalline schist allowed to identify two Paleoproterozoic metamorphism stages within the territory of the Anabar Shield with an age of about 1997 and 1919 million years. The peak conditions of granulite metamorphism are determined as 775±35 С and 7.5±0.7 kbar, the parameters of the regressive stage are 700 C and 7 kbar. The sequence of the rocks metamorphic transformations can be assumed: high-thermal metamorphism of the granulite facies (T ≤ 810 C) and subsequent sub-isobaric (about 7 kbar) cooling to 700 C with a water activity increase and formation of Grt-Amp paragenesis corresponding to the transition from the granulite to amphibolite facies. Data on the REE and other trace elements distribution in zircon and rock-forming minerals obtained by the ion microprobe analysis contribute significantly to the isotope-geochemical data interpretation. |
| first_indexed | 2024-04-10T21:23:08Z |
| format | Article |
| id | doaj.art-b7dc858277be4a8faa66a03a9d3aca41 |
| institution | Directory Open Access Journal |
| issn | 2411-3336 2541-9404 |
| language | English |
| last_indexed | 2024-04-10T21:23:08Z |
| publishDate | 2018-02-01 |
| publisher | Saint-Petersburg Mining University |
| record_format | Article |
| series | Записки Горного института |
| spelling | doaj.art-b7dc858277be4a8faa66a03a9d3aca412023-01-20T02:04:56ZengSaint-Petersburg Mining UniversityЗаписки Горного института2411-33362541-94042018-02-01229131310.25515/pmi.2018.1.1311907Age and metamorphic conditions of the granulites from Capral-Jegessky synclinoria, Anabar shieldL. Yu. Sergeeva0A. V. Berezin1N. I. Gusev2S. G. Skublov3A. E. Mel'nik4A.P. Karpinsky Russian Geological Research InstituteInstitute of Precambrian Geology and Geochronology RASA.P. Karpinsky Russian Geological Research InstituteInstitute of Precambrian Geology and Geochronology RASInstitute of Precambrian Geology and Geochronology RASThe paper presents the results of the isotope, geochemical and thermobarometric study of plagio-crystalline schist containing in the Upper Anabar series of the Anabar Shield. Granulite complexes of the paleoplatforms are the most important issue in addressing the fundamental problem of the Earth's crust origin and its composition. The early stages of crust formation which correspond to the deeply metamorphosed rocks of the platform basements, available for study within the shields, are of particular interest. The study of the age and metamorphic conditions of granulites by the case of the Upper Ananbar series allows specifying the stages the Anabar Shield's ancient crust formation. Isotope-geochemical (U-Pb geochronology for zircon and Sm-Nd for garnet-amphibole-WR) and thermoba-rometric (Theriak-Domino) studies of plagio-crystalline schist allowed to identify two Paleoproterozoic metamorphism stages within the territory of the Anabar Shield with an age of about 1997 and 1919 million years. The peak conditions of granulite metamorphism are determined as 775±35 С and 7.5±0.7 kbar, the parameters of the regressive stage are 700 C and 7 kbar. The sequence of the rocks metamorphic transformations can be assumed: high-thermal metamorphism of the granulite facies (T ≤ 810 C) and subsequent sub-isobaric (about 7 kbar) cooling to 700 C with a water activity increase and formation of Grt-Amp paragenesis corresponding to the transition from the granulite to amphibolite facies. Data on the REE and other trace elements distribution in zircon and rock-forming minerals obtained by the ion microprobe analysis contribute significantly to the isotope-geochemical data interpretation.https://pmi.spmi.ru/index.php/pmi/article/view/11907?setLocale=en_US |
| spellingShingle | L. Yu. Sergeeva A. V. Berezin N. I. Gusev S. G. Skublov A. E. Mel'nik Age and metamorphic conditions of the granulites from Capral-Jegessky synclinoria, Anabar shield Записки Горного института |
| title | Age and metamorphic conditions of the granulites from Capral-Jegessky synclinoria, Anabar shield |
| title_full | Age and metamorphic conditions of the granulites from Capral-Jegessky synclinoria, Anabar shield |
| title_fullStr | Age and metamorphic conditions of the granulites from Capral-Jegessky synclinoria, Anabar shield |
| title_full_unstemmed | Age and metamorphic conditions of the granulites from Capral-Jegessky synclinoria, Anabar shield |
| title_short | Age and metamorphic conditions of the granulites from Capral-Jegessky synclinoria, Anabar shield |
| title_sort | age and metamorphic conditions of the granulites from capral jegessky synclinoria anabar shield |
| url | https://pmi.spmi.ru/index.php/pmi/article/view/11907?setLocale=en_US |
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