1.90-1.88Ga arc magmatism of central Fennoscandia: geochemistry, U-Pb geochronology, Sm-Nd and Lu-Hf isotope systematics of plutonic-volcanic rocks from southern Finland
The earliest Svecofennian magmatism in southern Finland has been dated at 1.90-1.88Ga. As an example of this, the Orijärvi (ca. 1.89Ga) and Enklinge (ca. 1.88Ga) volcanic centres comprise bimodal plutonic batholiths surrounded by volcanic rocks of comparable ages and chemical compositions. Here, we...
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Universitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB)
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ftdoajarticles:oai:doaj.org/article:5df782e4a5f14be496fcc2c8a76aefa5 2023-11-12T04:17:02+01:00 1.90-1.88Ga arc magmatism of central Fennoscandia: geochemistry, U-Pb geochronology, Sm-Nd and Lu-Hf isotope systematics of plutonic-volcanic rocks from southern Finland J. KARA M. VÄISÄNEN Å. JOHANSSON Y. LAHAYE H. O'BRIEN O. EKLUND 2016-10-01T00:00:00Z https://doaj.org/article/5df782e4a5f14be496fcc2c8a76aefa5 EN eng Universitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB) https://revistes.ub.edu/index.php/GEOACTA/article/view/18249 https://doaj.org/toc/1696-5728 1696-5728 https://doaj.org/article/5df782e4a5f14be496fcc2c8a76aefa5 Geologica Acta, Vol 16, Iss 1 (2016) Fennoscandian shield Svecofennian orogeny Lu-Hf U-Pb Sm-Nd geochemistry Science Q Geology QE1-996.5 article 2016 ftdoajarticles 2023-10-22T00:36:06Z The earliest Svecofennian magmatism in southern Finland has been dated at 1.90-1.88Ga. As an example of this, the Orijärvi (ca. 1.89Ga) and Enklinge (ca. 1.88Ga) volcanic centres comprise bimodal plutonic batholiths surrounded by volcanic rocks of comparable ages and chemical compositions. Here, we report geochemical and Sm-Nd isotope data from intrusive and extrusive samples, combined with zircon U-Pb and Lu-Hf isotopes for granodiorites from both study areas. The samples range from gabbros to granites and indicate a subduction-related continental margin setting. The zircons from the Orijärvi granodiorite define an age of 1892±4Ma whereas the Enklinge granodiorite yields an age of 1882±6Ma. Several inherited ages of 2.25-1.95Ga as well as younger ages of 1.86-1.80Ga were found in the Enklinge granodiorite. The initial εNd values from the mafic rocks from both locations fall in the range +1.1 to +2.9 whereas the felsic rocks exhibit initial εNd values of -0.4 to +1.2. The magmatic zircons from the Orijärvi and Enklinge granodiorites show average initial εHf values of -1.1 (at 1892Ma) and zero (at 1882Ma), respectively, each with a spread of about 7 ε-units. The initial εHf values for the inherited zircons from Enklinge range from +3.5 to +7.6 with increasing age. The Sm-Nd data indicate that the mafic rocks were derived from a “mildly depleted” mantle source while the felsic rocks show larger crustal contribution. Also, the variation in εHf values indicates minor mixing between mildly depleted mantle derived magmas and crustal sources. U-Pb ages and Hf isotopes for inherited zircons in the Enklinge granodiorite suggest the presence of juvenile Svecofennian “proto-crust” at depth. Article in Journal/Newspaper Fennoscandia Fennoscandian Directory of Open Access Journals: DOAJ Articles |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Fennoscandian shield Svecofennian orogeny Lu-Hf U-Pb Sm-Nd geochemistry Science Q Geology QE1-996.5 |
spellingShingle |
Fennoscandian shield Svecofennian orogeny Lu-Hf U-Pb Sm-Nd geochemistry Science Q Geology QE1-996.5 J. KARA M. VÄISÄNEN Å. JOHANSSON Y. LAHAYE H. O'BRIEN O. EKLUND 1.90-1.88Ga arc magmatism of central Fennoscandia: geochemistry, U-Pb geochronology, Sm-Nd and Lu-Hf isotope systematics of plutonic-volcanic rocks from southern Finland |
topic_facet |
Fennoscandian shield Svecofennian orogeny Lu-Hf U-Pb Sm-Nd geochemistry Science Q Geology QE1-996.5 |
description |
The earliest Svecofennian magmatism in southern Finland has been dated at 1.90-1.88Ga. As an example of this, the Orijärvi (ca. 1.89Ga) and Enklinge (ca. 1.88Ga) volcanic centres comprise bimodal plutonic batholiths surrounded by volcanic rocks of comparable ages and chemical compositions. Here, we report geochemical and Sm-Nd isotope data from intrusive and extrusive samples, combined with zircon U-Pb and Lu-Hf isotopes for granodiorites from both study areas. The samples range from gabbros to granites and indicate a subduction-related continental margin setting. The zircons from the Orijärvi granodiorite define an age of 1892±4Ma whereas the Enklinge granodiorite yields an age of 1882±6Ma. Several inherited ages of 2.25-1.95Ga as well as younger ages of 1.86-1.80Ga were found in the Enklinge granodiorite. The initial εNd values from the mafic rocks from both locations fall in the range +1.1 to +2.9 whereas the felsic rocks exhibit initial εNd values of -0.4 to +1.2. The magmatic zircons from the Orijärvi and Enklinge granodiorites show average initial εHf values of -1.1 (at 1892Ma) and zero (at 1882Ma), respectively, each with a spread of about 7 ε-units. The initial εHf values for the inherited zircons from Enklinge range from +3.5 to +7.6 with increasing age. The Sm-Nd data indicate that the mafic rocks were derived from a “mildly depleted” mantle source while the felsic rocks show larger crustal contribution. Also, the variation in εHf values indicates minor mixing between mildly depleted mantle derived magmas and crustal sources. U-Pb ages and Hf isotopes for inherited zircons in the Enklinge granodiorite suggest the presence of juvenile Svecofennian “proto-crust” at depth. |
format |
Article in Journal/Newspaper |
author |
J. KARA M. VÄISÄNEN Å. JOHANSSON Y. LAHAYE H. O'BRIEN O. EKLUND |
author_facet |
J. KARA M. VÄISÄNEN Å. JOHANSSON Y. LAHAYE H. O'BRIEN O. EKLUND |
author_sort |
J. KARA |
title |
1.90-1.88Ga arc magmatism of central Fennoscandia: geochemistry, U-Pb geochronology, Sm-Nd and Lu-Hf isotope systematics of plutonic-volcanic rocks from southern Finland |
title_short |
1.90-1.88Ga arc magmatism of central Fennoscandia: geochemistry, U-Pb geochronology, Sm-Nd and Lu-Hf isotope systematics of plutonic-volcanic rocks from southern Finland |
title_full |
1.90-1.88Ga arc magmatism of central Fennoscandia: geochemistry, U-Pb geochronology, Sm-Nd and Lu-Hf isotope systematics of plutonic-volcanic rocks from southern Finland |
title_fullStr |
1.90-1.88Ga arc magmatism of central Fennoscandia: geochemistry, U-Pb geochronology, Sm-Nd and Lu-Hf isotope systematics of plutonic-volcanic rocks from southern Finland |
title_full_unstemmed |
1.90-1.88Ga arc magmatism of central Fennoscandia: geochemistry, U-Pb geochronology, Sm-Nd and Lu-Hf isotope systematics of plutonic-volcanic rocks from southern Finland |
title_sort |
1.90-1.88ga arc magmatism of central fennoscandia: geochemistry, u-pb geochronology, sm-nd and lu-hf isotope systematics of plutonic-volcanic rocks from southern finland |
publisher |
Universitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB) |
publishDate |
2016 |
url |
https://doaj.org/article/5df782e4a5f14be496fcc2c8a76aefa5 |
genre |
Fennoscandia Fennoscandian |
genre_facet |
Fennoscandia Fennoscandian |
op_source |
Geologica Acta, Vol 16, Iss 1 (2016) |
op_relation |
https://revistes.ub.edu/index.php/GEOACTA/article/view/18249 https://doaj.org/toc/1696-5728 1696-5728 https://doaj.org/article/5df782e4a5f14be496fcc2c8a76aefa5 |
_version_ |
1782334033639768064 |