Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny
Abstract The Fennoscandian Shield in central Sweden displays a complex structural and compositional architecture that is mainly related to the Proterozoic history of the Baltica paleocontinent. In its western parts, the Precambrian basement is covered by the allochthonous rocks of the Caledonide oro...
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ftoslouniv:oai:www.duo.uio.no:10852/100967 2023-05-15T16:12:55+02:00 Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny ENEngelskEnglishLarge-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny Lescoutre, Rodolphe Almqvist, Bjarne Koyi, Hemin Berthet, Théo Hedin, Peter Galland, Olivier Brahimi, Sonia Lorenz, Henning Juhlin, Christopher 2022-12-02T09:57:21Z http://hdl.handle.net/10852/100967 https://doi.org/10.1130/B36202.1 EN eng Lescoutre, Rodolphe Almqvist, Bjarne Koyi, Hemin Berthet, Théo Hedin, Peter Galland, Olivier Brahimi, Sonia Lorenz, Henning Juhlin, Christopher . Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny. Geological Society of America Bulletin. 2022, 134(11-12), 3022-3048 http://hdl.handle.net/10852/100967 2087597 info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Geological Society of America Bulletin&rft.volume=134&rft.spage=3022&rft.date=2022 Geological Society of America Bulletin 134 11-12 3022 3048 https://doi.org/10.1130/B36202.1 Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ CC-BY 0016-7606 Journal article Tidsskriftartikkel Peer reviewed PublishedVersion 2022 ftoslouniv https://doi.org/10.1130/B36202.1 2023-03-08T23:36:47Z Abstract The Fennoscandian Shield in central Sweden displays a complex structural and compositional architecture that is mainly related to the Proterozoic history of the Baltica paleocontinent. In its western parts, the Precambrian basement is covered by the allochthonous rocks of the Caledonide orogen, and direct information about the underlying crust is restricted to a few unevenly distributed basement windows in western Sweden and Norway. In this study, we use preliminary results from the second borehole of the Collisional Orogeny in the Scandinavian Caledonides project (COSC-2), new gravity data, forward gravity, and magnetic modeling and interpretation of seismic reflection profiles to assess the 3-D architecture of the basement. Our results reveal a wide (~100 km) and dense network of mainly flat-lying and saucer-shaped dolerites intruding the volcanic and granitic upper crustal rocks of the Transscandinavian Igneous Belt. Similar intrusion geometries related to 1.2 Ga dolerites can be recognized in the Fennoscandian Shield. We discuss that the formation of these sill complexes occurred in a lithologically and structurally heterogeneous crust during transtension, which is in disagreement with the current understanding of sill emplacement that involves crustal shortening, layering, or anisotropy of the host rock. Our seismic interpretation and the structural observations from the COSC-2 drilling show that part of the Caledonian-related basement deformation was localized along the margins of the dolerite sheets. We propose that the dolerite intrusion geometry, akin to a flat-ramp geometry, guided the basement deformation during the Caledonian orogeny. Article in Journal/Newspaper Fennoscandian Universitet i Oslo: Digitale utgivelser ved UiO (DUO) Norway GSA Bulletin 134 11-12 3022 3048 |
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Open Polar |
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Universitet i Oslo: Digitale utgivelser ved UiO (DUO) |
op_collection_id |
ftoslouniv |
language |
English |
description |
Abstract The Fennoscandian Shield in central Sweden displays a complex structural and compositional architecture that is mainly related to the Proterozoic history of the Baltica paleocontinent. In its western parts, the Precambrian basement is covered by the allochthonous rocks of the Caledonide orogen, and direct information about the underlying crust is restricted to a few unevenly distributed basement windows in western Sweden and Norway. In this study, we use preliminary results from the second borehole of the Collisional Orogeny in the Scandinavian Caledonides project (COSC-2), new gravity data, forward gravity, and magnetic modeling and interpretation of seismic reflection profiles to assess the 3-D architecture of the basement. Our results reveal a wide (~100 km) and dense network of mainly flat-lying and saucer-shaped dolerites intruding the volcanic and granitic upper crustal rocks of the Transscandinavian Igneous Belt. Similar intrusion geometries related to 1.2 Ga dolerites can be recognized in the Fennoscandian Shield. We discuss that the formation of these sill complexes occurred in a lithologically and structurally heterogeneous crust during transtension, which is in disagreement with the current understanding of sill emplacement that involves crustal shortening, layering, or anisotropy of the host rock. Our seismic interpretation and the structural observations from the COSC-2 drilling show that part of the Caledonian-related basement deformation was localized along the margins of the dolerite sheets. We propose that the dolerite intrusion geometry, akin to a flat-ramp geometry, guided the basement deformation during the Caledonian orogeny. |
format |
Article in Journal/Newspaper |
author |
Lescoutre, Rodolphe Almqvist, Bjarne Koyi, Hemin Berthet, Théo Hedin, Peter Galland, Olivier Brahimi, Sonia Lorenz, Henning Juhlin, Christopher |
spellingShingle |
Lescoutre, Rodolphe Almqvist, Bjarne Koyi, Hemin Berthet, Théo Hedin, Peter Galland, Olivier Brahimi, Sonia Lorenz, Henning Juhlin, Christopher Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny |
author_facet |
Lescoutre, Rodolphe Almqvist, Bjarne Koyi, Hemin Berthet, Théo Hedin, Peter Galland, Olivier Brahimi, Sonia Lorenz, Henning Juhlin, Christopher |
author_sort |
Lescoutre, Rodolphe |
title |
Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny |
title_short |
Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny |
title_full |
Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny |
title_fullStr |
Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny |
title_full_unstemmed |
Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny |
title_sort |
large-scale, flat-lying mafic intrusions in the baltican crust and their influence on basement deformation during the caledonian orogeny |
publishDate |
2022 |
url |
http://hdl.handle.net/10852/100967 https://doi.org/10.1130/B36202.1 |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Fennoscandian |
genre_facet |
Fennoscandian |
op_source |
0016-7606 |
op_relation |
Lescoutre, Rodolphe Almqvist, Bjarne Koyi, Hemin Berthet, Théo Hedin, Peter Galland, Olivier Brahimi, Sonia Lorenz, Henning Juhlin, Christopher . Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny. Geological Society of America Bulletin. 2022, 134(11-12), 3022-3048 http://hdl.handle.net/10852/100967 2087597 info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Geological Society of America Bulletin&rft.volume=134&rft.spage=3022&rft.date=2022 Geological Society of America Bulletin 134 11-12 3022 3048 https://doi.org/10.1130/B36202.1 |
op_rights |
Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1130/B36202.1 |
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GSA Bulletin |
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134 |
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11-12 |
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3022 |
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3048 |
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