Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding
Early Precambrian retrogressed eclogites are abundant in the central and northern parts of the Belomorian Province of the Fennoscandian Shield (Gridino + Keret and Salma + Kuru-Vaara study areas, respectively). Older and younger eclogites are recognized and their Archean and Paleoproterozoic ages ar...
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2021
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ftdoajarticles:oai:doaj.org/article:b5de6c4275ce4830802d8bc502838200 2023-05-15T16:12:54+02:00 Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding Oleg I. Volodichev Oleg A. Maksimov Tatiana I. Kuzenko Alexander I. Slabunov 2021-09-01T00:00:00Z https://doi.org/10.3390/min11101029 https://doaj.org/article/b5de6c4275ce4830802d8bc502838200 EN eng MDPI AG https://www.mdpi.com/2075-163X/11/10/1029 https://doaj.org/toc/2075-163X doi:10.3390/min11101029 2075-163X https://doaj.org/article/b5de6c4275ce4830802d8bc502838200 Minerals, Vol 11, Iss 1029, p 1029 (2021) Archean eclogite zircon omphacite geochronology geochemistry Mineralogy QE351-399.2 article 2021 ftdoajarticles https://doi.org/10.3390/min11101029 2022-12-31T07:46:49Z Early Precambrian retrogressed eclogites are abundant in the central and northern parts of the Belomorian Province of the Fennoscandian Shield (Gridino + Keret and Salma + Kuru-Vaara study areas, respectively). Older and younger eclogites are recognized and their Archean and Paleoproterozoic ages are argued. Archean eclogites are intensely retrogressed and occur in amphibolite boudins in the tonalite-trondhjemite-granodiorite (TTG) gneiss matrix of the Archean Gridino eclogite-bearing mélange. Less retrogressed Paleoproterozoic eclogites form patches in mafic dikes and some amphibolite boudins; their Paleoproterozoic age is supported by U-Pb/SIMS data on zircons depleted in heavy rare earth elements (REE) with omphacite, garnet, and kyanite inclusions, and Sm-Nd and Lu-Hf mineral isochrons. Archean eclogites contain Archean heavy rare-earth elements (REE)-depleted zircons with garnet and zoisite inclusions and Archean garnets. No omphacite inclusions were found in these zircons, and this fact was considered as evidence against the existence of Archean eclogites. This study reports on the first finding of omphacite (23–25% Jd ) inclusions in 2.68 Ga metamorphic zircons from eclogites from the Gridino eclogite-bearing mélange. The zircons are poorly enriched in heavy REE and display a weak negative Eu-anomaly but a poor positive Ce-anomaly typical of eclogitic zircons. Thus, zircons with these decisive features provide evidence for an Archean eclogite-facies metamorphism. Article in Journal/Newspaper Fennoscandian Directory of Open Access Journals: DOAJ Articles Gridino ENVELOPE(34.675,34.675,65.923,65.923) Keret ENVELOPE(33.567,33.567,66.283,66.283) Keret’ ENVELOPE(32.900,32.900,66.196,66.196) Salma ENVELOPE(32.133,32.133,65.817,65.817) Vaara ENVELOPE(24.886,24.886,67.360,67.360) Minerals 11 10 1029 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Archean eclogite zircon omphacite geochronology geochemistry Mineralogy QE351-399.2 |
spellingShingle |
Archean eclogite zircon omphacite geochronology geochemistry Mineralogy QE351-399.2 Oleg I. Volodichev Oleg A. Maksimov Tatiana I. Kuzenko Alexander I. Slabunov Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding |
topic_facet |
Archean eclogite zircon omphacite geochronology geochemistry Mineralogy QE351-399.2 |
description |
Early Precambrian retrogressed eclogites are abundant in the central and northern parts of the Belomorian Province of the Fennoscandian Shield (Gridino + Keret and Salma + Kuru-Vaara study areas, respectively). Older and younger eclogites are recognized and their Archean and Paleoproterozoic ages are argued. Archean eclogites are intensely retrogressed and occur in amphibolite boudins in the tonalite-trondhjemite-granodiorite (TTG) gneiss matrix of the Archean Gridino eclogite-bearing mélange. Less retrogressed Paleoproterozoic eclogites form patches in mafic dikes and some amphibolite boudins; their Paleoproterozoic age is supported by U-Pb/SIMS data on zircons depleted in heavy rare earth elements (REE) with omphacite, garnet, and kyanite inclusions, and Sm-Nd and Lu-Hf mineral isochrons. Archean eclogites contain Archean heavy rare-earth elements (REE)-depleted zircons with garnet and zoisite inclusions and Archean garnets. No omphacite inclusions were found in these zircons, and this fact was considered as evidence against the existence of Archean eclogites. This study reports on the first finding of omphacite (23–25% Jd ) inclusions in 2.68 Ga metamorphic zircons from eclogites from the Gridino eclogite-bearing mélange. The zircons are poorly enriched in heavy REE and display a weak negative Eu-anomaly but a poor positive Ce-anomaly typical of eclogitic zircons. Thus, zircons with these decisive features provide evidence for an Archean eclogite-facies metamorphism. |
format |
Article in Journal/Newspaper |
author |
Oleg I. Volodichev Oleg A. Maksimov Tatiana I. Kuzenko Alexander I. Slabunov |
author_facet |
Oleg I. Volodichev Oleg A. Maksimov Tatiana I. Kuzenko Alexander I. Slabunov |
author_sort |
Oleg I. Volodichev |
title |
Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding |
title_short |
Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding |
title_full |
Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding |
title_fullStr |
Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding |
title_full_unstemmed |
Archean Zircons with Omphacite Inclusions from Eclogites of the Belomorian Province, Fennoscandian Shield: The First Finding |
title_sort |
archean zircons with omphacite inclusions from eclogites of the belomorian province, fennoscandian shield: the first finding |
publisher |
MDPI AG |
publishDate |
2021 |
url |
https://doi.org/10.3390/min11101029 https://doaj.org/article/b5de6c4275ce4830802d8bc502838200 |
long_lat |
ENVELOPE(34.675,34.675,65.923,65.923) ENVELOPE(33.567,33.567,66.283,66.283) ENVELOPE(32.900,32.900,66.196,66.196) ENVELOPE(32.133,32.133,65.817,65.817) ENVELOPE(24.886,24.886,67.360,67.360) |
geographic |
Gridino Keret Keret’ Salma Vaara |
geographic_facet |
Gridino Keret Keret’ Salma Vaara |
genre |
Fennoscandian |
genre_facet |
Fennoscandian |
op_source |
Minerals, Vol 11, Iss 1029, p 1029 (2021) |
op_relation |
https://www.mdpi.com/2075-163X/11/10/1029 https://doaj.org/toc/2075-163X doi:10.3390/min11101029 2075-163X https://doaj.org/article/b5de6c4275ce4830802d8bc502838200 |
op_doi |
https://doi.org/10.3390/min11101029 |
container_title |
Minerals |
container_volume |
11 |
container_issue |
10 |
container_start_page |
1029 |
_version_ |
1765998504732262400 |