Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield
Arclogites, i.e., lower crustal gamet-pyroxenite cumulates, are suggested to play an important role in controlling magma differentiation in modem continental arcs. Until now, arclogite-related magmatism has only been described from the Phanerozoic Era. The Svecofennian orogen in the central Fennosca...
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2022
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/346369 2024-06-23T07:52:44+00:00 Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield Paleoproterotsooisten arclogiittien jäljillä - Muutos 1.88 Ga kalkkialkalisesta magmatismista 1.86 Ga korkean Nb:n ja adakiitti-tyyppiseen magmatismiin Fennoskandian kilven keskiosissa Kara, Jaakko Väisänen, Markku Heinonen, Jussi S. Lahaye, Yann O'Brien, Hugh Huhma, Hannu Petrology and Geochemistry Department of Geosciences and Geography 2022-07-22T22:03:12Z 21 application/pdf http://hdl.handle.net/10138/346369 eng eng Elsevier Scientific Publ. Co 10.1016/j.lithos.2020.105663 Kara , J , Väisänen , M , Heinonen , J S , Lahaye , Y , O'Brien , H & Huhma , H 2020 , ' Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield ' , Lithos , vol. 372 , 105663 . https://doi.org/10.1016/j.lithos.2020.105663 ORCID: /0000-0001-8998-4357/work/160774812 http://hdl.handle.net/10138/346369 db37506a-33da-41b6-8c66-287181a21e09 000571822300006 cc_by_nc_nd info:eu-repo/semantics/openAccess openAccess Geosciences Arclogite High-Nb gabbro Svecofennian orogen Geochemistry Sm-Nd isotopes Zircon U-Pb-Hf isotopes FINLAND GRANITOID COMPLEX PB ZIRCON AGES U-PB VOLCANIC-ROCKS SIERRA-NEVADA ELEMENT FRACTIONATION BASALTIC MAGMATISM CONTINENTAL-CRUST GARNET PYROXENITE HF ISOTOPES Article acceptedVersion 2022 ftunivhelsihelda 2024-06-04T14:34:43Z Arclogites, i.e., lower crustal gamet-pyroxenite cumulates, are suggested to play an important role in controlling magma differentiation in modem continental arcs. Until now, arclogite-related magmatism has only been described from the Phanerozoic Era. The Svecofennian orogen in the central Fennoscandian Shield hosts a rare association of 1.86 Ga igneous rocks geochemically distinct from the surrounding and much more abundant 1.90-1.87 Ga subduction-related talc-alkaline magmatism. The 1.86 Ga magmatic rocks are divided into three groups: 1) high-Nb gabbros (HNB) which are enriched in Fe2O3T, TiO2, P2O5, F. LILE, and HFSE (especially Nb: 18.9-44 ppm), show positive initial epsilon(Nd) value, and near-chondritic but variable initial zircon epsilon(Hf) values; 2) high-Mg gabbros (HMG) which are characterised by high MgO, CaO, Cr and Ni contents, slight enrichment in LILE, positive epsilon(Hf), and positive but variable zircon epsilon(Hf) values; 3) adakite-like rocks showing high Al2O3 and Na2O contents, slight enrichment in LILE, relative depletion in some HFSE, positive CNd value, and chondritic to negative zircon epsilon(Nd) values. The three groups yield zircon U-Pb ages of similar to 1.86 Ga and exhibit undeformed textures in contrast to the surrounding supracrustal rocks metamorphosed at similar to 1.88 Ga. The ages and compositions are dearly different from the adjacent 1.90-1.87 Ga arc-related igneous rocks suggesting a distinct origin. Despite similar ages and close spatial relationship, separate sources are required for each of the different 1.86 Ga rock groups. Trace element modelling of partial melting suggests that arclogites, with compositions similar to pyroxenite xenoliths found in the kimberlite pipes of eastern Finland, are the source for the HNB rocks. In contrast, subduction-modified mantle peridotite is the source for the HMG rocks, and a mafic lower crustal source is suggested for the adakite-like rocks. The following geodynamic model is suggested: (rutile-bearing) arclogite formation at ... Article in Journal/Newspaper Fennoscandian HELDA – University of Helsinki Open Repository Lithos 372-373 105663 |
institution |
Open Polar |
collection |
HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
Geosciences Arclogite High-Nb gabbro Svecofennian orogen Geochemistry Sm-Nd isotopes Zircon U-Pb-Hf isotopes FINLAND GRANITOID COMPLEX PB ZIRCON AGES U-PB VOLCANIC-ROCKS SIERRA-NEVADA ELEMENT FRACTIONATION BASALTIC MAGMATISM CONTINENTAL-CRUST GARNET PYROXENITE HF ISOTOPES |
spellingShingle |
Geosciences Arclogite High-Nb gabbro Svecofennian orogen Geochemistry Sm-Nd isotopes Zircon U-Pb-Hf isotopes FINLAND GRANITOID COMPLEX PB ZIRCON AGES U-PB VOLCANIC-ROCKS SIERRA-NEVADA ELEMENT FRACTIONATION BASALTIC MAGMATISM CONTINENTAL-CRUST GARNET PYROXENITE HF ISOTOPES Kara, Jaakko Väisänen, Markku Heinonen, Jussi S. Lahaye, Yann O'Brien, Hugh Huhma, Hannu Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield |
topic_facet |
Geosciences Arclogite High-Nb gabbro Svecofennian orogen Geochemistry Sm-Nd isotopes Zircon U-Pb-Hf isotopes FINLAND GRANITOID COMPLEX PB ZIRCON AGES U-PB VOLCANIC-ROCKS SIERRA-NEVADA ELEMENT FRACTIONATION BASALTIC MAGMATISM CONTINENTAL-CRUST GARNET PYROXENITE HF ISOTOPES |
description |
Arclogites, i.e., lower crustal gamet-pyroxenite cumulates, are suggested to play an important role in controlling magma differentiation in modem continental arcs. Until now, arclogite-related magmatism has only been described from the Phanerozoic Era. The Svecofennian orogen in the central Fennoscandian Shield hosts a rare association of 1.86 Ga igneous rocks geochemically distinct from the surrounding and much more abundant 1.90-1.87 Ga subduction-related talc-alkaline magmatism. The 1.86 Ga magmatic rocks are divided into three groups: 1) high-Nb gabbros (HNB) which are enriched in Fe2O3T, TiO2, P2O5, F. LILE, and HFSE (especially Nb: 18.9-44 ppm), show positive initial epsilon(Nd) value, and near-chondritic but variable initial zircon epsilon(Hf) values; 2) high-Mg gabbros (HMG) which are characterised by high MgO, CaO, Cr and Ni contents, slight enrichment in LILE, positive epsilon(Hf), and positive but variable zircon epsilon(Hf) values; 3) adakite-like rocks showing high Al2O3 and Na2O contents, slight enrichment in LILE, relative depletion in some HFSE, positive CNd value, and chondritic to negative zircon epsilon(Nd) values. The three groups yield zircon U-Pb ages of similar to 1.86 Ga and exhibit undeformed textures in contrast to the surrounding supracrustal rocks metamorphosed at similar to 1.88 Ga. The ages and compositions are dearly different from the adjacent 1.90-1.87 Ga arc-related igneous rocks suggesting a distinct origin. Despite similar ages and close spatial relationship, separate sources are required for each of the different 1.86 Ga rock groups. Trace element modelling of partial melting suggests that arclogites, with compositions similar to pyroxenite xenoliths found in the kimberlite pipes of eastern Finland, are the source for the HNB rocks. In contrast, subduction-modified mantle peridotite is the source for the HMG rocks, and a mafic lower crustal source is suggested for the adakite-like rocks. The following geodynamic model is suggested: (rutile-bearing) arclogite formation at ... |
author2 |
Petrology and Geochemistry Department of Geosciences and Geography |
format |
Article in Journal/Newspaper |
author |
Kara, Jaakko Väisänen, Markku Heinonen, Jussi S. Lahaye, Yann O'Brien, Hugh Huhma, Hannu |
author_facet |
Kara, Jaakko Väisänen, Markku Heinonen, Jussi S. Lahaye, Yann O'Brien, Hugh Huhma, Hannu |
author_sort |
Kara, Jaakko |
title |
Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield |
title_short |
Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield |
title_full |
Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield |
title_fullStr |
Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield |
title_full_unstemmed |
Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield |
title_sort |
tracing arclogites in the paleoproterozoic era - a shift from 1.88 ga calc-alkaline to 1.86 ga high-nb and adakite-like magmatism in central fennoscandian shield |
publisher |
Elsevier Scientific Publ. Co |
publishDate |
2022 |
url |
http://hdl.handle.net/10138/346369 |
genre |
Fennoscandian |
genre_facet |
Fennoscandian |
op_relation |
10.1016/j.lithos.2020.105663 Kara , J , Väisänen , M , Heinonen , J S , Lahaye , Y , O'Brien , H & Huhma , H 2020 , ' Tracing arclogites in the Paleoproterozoic Era - A shift from 1.88 Ga calc-alkaline to 1.86 Ga high-Nb and adakite-like magmatism in central Fennoscandian Shield ' , Lithos , vol. 372 , 105663 . https://doi.org/10.1016/j.lithos.2020.105663 ORCID: /0000-0001-8998-4357/work/160774812 http://hdl.handle.net/10138/346369 db37506a-33da-41b6-8c66-287181a21e09 000571822300006 |
op_rights |
cc_by_nc_nd info:eu-repo/semantics/openAccess openAccess |
container_title |
Lithos |
container_volume |
372-373 |
container_start_page |
105663 |
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1802644114854903808 |