U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphism
Zircons from a felsic volcanic rock in the Toija Formation and a synvolcanic gabbro intrusion in the Salittu Formation within the Orijärvi area were dated by U-Th-Pb SIMS in order to provide depositional constraints on these formations. Zircon crystals from the felsic rock preserve a two-stage cryst...
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| Format: | Article |
| Language: | English |
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Geological Society of Finland
2008-12-01
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| Series: | Bulletin of the Geological Society of Finland |
| Subjects: | |
| Online Access: | http://www.geologinenseura.fi/bulletin/Volume80/Vaisanen.pdf |
| _version_ | 1828774559656968192 |
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| author | M. Väisänen C.L. Kirkland |
| author_facet | M. Väisänen C.L. Kirkland |
| author_sort | M. Väisänen |
| collection | DOAJ |
| description | Zircons from a felsic volcanic rock in the Toija Formation and a synvolcanic gabbro intrusion in the Salittu Formation within the Orijärvi area were dated by U-Th-Pb SIMS in order to provide depositional constraints on these formations. Zircon crystals from the felsic rock preserve a two-stage crystallisation history with zoned core domains and homogeneous rim domains. Inner domains yield a 1878 ± 4 Ma concordia age, interpreted to determine the crystallisation of this rock. Rims yield a 1815 ± 3 Ma concordia age interpreted to determine the regional metamorphism. Small rounded zircon grains from the Salittu gabbro, located within the Jyly shear zone, yield a concordia age of 1792 ± 5 Ma. We interpret the grain textures to suggest that they recrystallised from inherited zircon seeds during the heat and fluid flow into the shear zone. Although no direct ages for the Salittu Formation have been recovered, field relationships imply that it was deposited between 1878−1875 Ma. |
| first_indexed | 2024-12-11T15:23:19Z |
| format | Article |
| id | doaj.art-d66f3df1c24c418f9d21400c7794e852 |
| institution | Directory Open Access Journal |
| issn | 0367-5211 1799-4632 |
| language | English |
| last_indexed | 2024-12-11T15:23:19Z |
| publishDate | 2008-12-01 |
| publisher | Geological Society of Finland |
| record_format | Article |
| series | Bulletin of the Geological Society of Finland |
| spelling | doaj.art-d66f3df1c24c418f9d21400c7794e8522022-12-22T01:00:17ZengGeological Society of FinlandBulletin of the Geological Society of Finland0367-52111799-46322008-12-01802738710.17741/bgsf/80.2.001U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphismM. VäisänenC.L. KirklandZircons from a felsic volcanic rock in the Toija Formation and a synvolcanic gabbro intrusion in the Salittu Formation within the Orijärvi area were dated by U-Th-Pb SIMS in order to provide depositional constraints on these formations. Zircon crystals from the felsic rock preserve a two-stage crystallisation history with zoned core domains and homogeneous rim domains. Inner domains yield a 1878 ± 4 Ma concordia age, interpreted to determine the crystallisation of this rock. Rims yield a 1815 ± 3 Ma concordia age interpreted to determine the regional metamorphism. Small rounded zircon grains from the Salittu gabbro, located within the Jyly shear zone, yield a concordia age of 1792 ± 5 Ma. We interpret the grain textures to suggest that they recrystallised from inherited zircon seeds during the heat and fluid flow into the shear zone. Although no direct ages for the Salittu Formation have been recovered, field relationships imply that it was deposited between 1878−1875 Ma.http://www.geologinenseura.fi/bulletin/Volume80/Vaisanen.pdfmetavolcanic rocksgabbrosvolcanismvolcanic arcsmetamorphismabsolute ageU/Th/PbzirconProterozoicPaleoproterozoicToijaOrijärviSalittuSuomusjärviFinland |
| spellingShingle | M. Väisänen C.L. Kirkland U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphism Bulletin of the Geological Society of Finland metavolcanic rocks gabbros volcanism volcanic arcs metamorphism absolute age U/Th/Pb zircon Proterozoic Paleoproterozoic Toija Orijärvi Salittu Suomusjärvi Finland |
| title | U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphism |
| title_full | U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphism |
| title_fullStr | U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphism |
| title_full_unstemmed | U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphism |
| title_short | U-Th-Pb zircon geochronology on igneous rocks in the Toija and Salittu Formations, Orijärvi area, southwestern Finland: Constraints on the age of volcanism and metamorphism |
| title_sort | u th pb zircon geochronology on igneous rocks in the toija and salittu formations orijarvi area southwestern finland constraints on the age of volcanism and metamorphism |
| topic | metavolcanic rocks gabbros volcanism volcanic arcs metamorphism absolute age U/Th/Pb zircon Proterozoic Paleoproterozoic Toija Orijärvi Salittu Suomusjärvi Finland |
| url | http://www.geologinenseura.fi/bulletin/Volume80/Vaisanen.pdf |
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