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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ftuabarcelonapb:oai:ddd.uab.cat:188597 2024-09-15T18:06:01+00:00 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 Kara, J. Väisänen, M. Johansson, A. Lahaye, Y. O'Brien, H. Eklund, O. 2018 application/pdf https://ddd.uab.cat/record/188597 eng eng Geologica acta Vol. 16 Núm. 1 (March 2018), p. 1-23 https://ddd.uab.cat/record/188597 urn:10.1344/GeologicaActa2018.16.1.1 urn:oai:ddd.uab.cat:188597 urn:oai:raco.cat:article/335933 urn:scopus_id:85044603633 urn:wos_id:000428895300001 urn:oai:revistes.ub.edu:article/18249 open access Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original. https://creativecommons.org/licenses/by-sa/4.0/ Fennoscandian shield Svecofennian orogeny Lu-Hf U-Pb Sm-Nd Geochemistry Article 2018 ftuabarcelonapb 2024-08-06T14:30:49Z 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 Universitat Autònoma de Barcelona: Dipòsit Digital de Documents de la UAB |
institution |
Open Polar |
collection |
Universitat Autònoma de Barcelona: Dipòsit Digital de Documents de la UAB |
op_collection_id |
ftuabarcelonapb |
language |
English |
topic |
Fennoscandian shield Svecofennian orogeny Lu-Hf U-Pb Sm-Nd Geochemistry |
spellingShingle |
Fennoscandian shield Svecofennian orogeny Lu-Hf U-Pb Sm-Nd Geochemistry Kara, J. Väisänen, M. Johansson, A. Lahaye, Y. O'Brien, H. Eklund, O. 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 |
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 |
Kara, J. Väisänen, M. Johansson, A. Lahaye, Y. O'Brien, H. Eklund, O. |
author_facet |
Kara, J. Väisänen, M. Johansson, A. Lahaye, Y. O'Brien, H. Eklund, O. |
author_sort |
Kara, J. |
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 |
publishDate |
2018 |
url |
https://ddd.uab.cat/record/188597 |
genre |
Fennoscandia Fennoscandian |
genre_facet |
Fennoscandia Fennoscandian |
op_relation |
Geologica acta Vol. 16 Núm. 1 (March 2018), p. 1-23 https://ddd.uab.cat/record/188597 urn:10.1344/GeologicaActa2018.16.1.1 urn:oai:ddd.uab.cat:188597 urn:oai:raco.cat:article/335933 urn:scopus_id:85044603633 urn:wos_id:000428895300001 urn:oai:revistes.ub.edu:article/18249 |
op_rights |
open access Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original. https://creativecommons.org/licenses/by-sa/4.0/ |
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1810443531150426112 |