Post-Caledonian brittle deformation in the Bergen area, West Norway: results from K-Ar illite fault gouge dating
Post-Caledonian extension during orogenic collapse and Mesozoic rifting in the West Norway northern North Sea region was accommodated by the formation and repeated reactivation of ductile shear zones and brittle faults. Offshore, the Late Palaeozoic Mesozoic rift history is relatively well known; ex...
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Geological Soc Norway
2016
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Online Access: | https://resolver.sub.uni-goettingen.de/purl?gro-2/41721 https://resolver.sub.uni-goettingen.de/purl?gs-1/14300 https://doi.org/10.17850/njg96-3-06 |
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ftsubgoettingen:oai:publications.goettingen-research-online.de:2/41721 2023-09-05T13:21:45+02:00 Post-Caledonian brittle deformation in the Bergen area, West Norway: results from K-Ar illite fault gouge dating Ksienzyk, Anna K. Wemmer, Klaus Jacobs, Joachim Fossen, Haakon Schomberg, Anna C. Sussenberger, Annette Luensdorf, Nils Keno Bastesen, Eivind 2016 https://resolver.sub.uni-goettingen.de/purl?gro-2/41721 https://resolver.sub.uni-goettingen.de/purl?gs-1/14300 https://doi.org/10.17850/njg96-3-06 unknown Geological Soc Norway 0029-196X https://resolver.sub.uni-goettingen.de/purl?gro-2/41721 doi:10.17850/njg96-3-06 000390982500006 https://resolver.sub.uni-goettingen.de/purl?gs-1/14300 CC BY 4.0 https://creativecommons.org/licenses/by/4.0/ journal_article published yes published_version 2016 ftsubgoettingen https://doi.org/10.17850/njg96-3-06 2023-08-20T22:13:32Z Post-Caledonian extension during orogenic collapse and Mesozoic rifting in the West Norway northern North Sea region was accommodated by the formation and repeated reactivation of ductile shear zones and brittle faults. Offshore, the Late Palaeozoic Mesozoic rift history is relatively well known; extension occurred mainly during two rift phases in the Permo-Triassic (Phase 1) and Mid Late Jurassic (Phase 2). Normal faults in the northern North Sea, e.g., on the Horda Platform, in the East Shetland Basin and in the Viking Graben, were initiated or reactivated during both rift phases. Onshore, on the other hand, information on periods of tectonic activity is sparse as faults in crystalline basement rocks are difficult to date. K- Ar dating of illite that grows synkinematically in fine-grained fault rocks (gouge) can greatly help to determine the time of fault activity, and we apply the method to nine faults from the Bergen area. The K-Ar ages are complemented with X-ray diffraction analyses to determine the mineralogy, illite crystallinity and polytype composition of the samples. Based on these new data, four periods of onshore fault activity could be defined: (1) the earliest growth of fault-related illite in the Late Devonian Early Carboniferous (>340 Ma) marks the waning stages of orogenic collapse; (2) widespread latest Carboniferous-Mid Permian (305-270 Ma) fault activity is interpreted as the onset of Phase 1 rifting, contemporaneous with rift-related volcanism in the central North Sea and Oslo Rift; (3) a Late Triassic Early Jurassic (215-180 Ma) period of onshore fault activity postdates Phase 1 rifting and predates Phase 2 rifting and is currently poorly documented in offshore areas; and (4) Early Cretaceous (120-110 Ma) fault reactivation can be linked either to late Phase 2 North Sea rifting or to North Atlantic rifting. University of Bergen; VISTA; Academy of Science and Letters; Statoil Article in Journal/Newspaper North Atlantic Georg-August-Universität Göttingen: GoeScholar Norway Bergen Norwegian Journal of Geology |
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Georg-August-Universität Göttingen: GoeScholar |
op_collection_id |
ftsubgoettingen |
language |
unknown |
description |
Post-Caledonian extension during orogenic collapse and Mesozoic rifting in the West Norway northern North Sea region was accommodated by the formation and repeated reactivation of ductile shear zones and brittle faults. Offshore, the Late Palaeozoic Mesozoic rift history is relatively well known; extension occurred mainly during two rift phases in the Permo-Triassic (Phase 1) and Mid Late Jurassic (Phase 2). Normal faults in the northern North Sea, e.g., on the Horda Platform, in the East Shetland Basin and in the Viking Graben, were initiated or reactivated during both rift phases. Onshore, on the other hand, information on periods of tectonic activity is sparse as faults in crystalline basement rocks are difficult to date. K- Ar dating of illite that grows synkinematically in fine-grained fault rocks (gouge) can greatly help to determine the time of fault activity, and we apply the method to nine faults from the Bergen area. The K-Ar ages are complemented with X-ray diffraction analyses to determine the mineralogy, illite crystallinity and polytype composition of the samples. Based on these new data, four periods of onshore fault activity could be defined: (1) the earliest growth of fault-related illite in the Late Devonian Early Carboniferous (>340 Ma) marks the waning stages of orogenic collapse; (2) widespread latest Carboniferous-Mid Permian (305-270 Ma) fault activity is interpreted as the onset of Phase 1 rifting, contemporaneous with rift-related volcanism in the central North Sea and Oslo Rift; (3) a Late Triassic Early Jurassic (215-180 Ma) period of onshore fault activity postdates Phase 1 rifting and predates Phase 2 rifting and is currently poorly documented in offshore areas; and (4) Early Cretaceous (120-110 Ma) fault reactivation can be linked either to late Phase 2 North Sea rifting or to North Atlantic rifting. University of Bergen; VISTA; Academy of Science and Letters; Statoil |
format |
Article in Journal/Newspaper |
author |
Ksienzyk, Anna K. Wemmer, Klaus Jacobs, Joachim Fossen, Haakon Schomberg, Anna C. Sussenberger, Annette Luensdorf, Nils Keno Bastesen, Eivind |
spellingShingle |
Ksienzyk, Anna K. Wemmer, Klaus Jacobs, Joachim Fossen, Haakon Schomberg, Anna C. Sussenberger, Annette Luensdorf, Nils Keno Bastesen, Eivind Post-Caledonian brittle deformation in the Bergen area, West Norway: results from K-Ar illite fault gouge dating |
author_facet |
Ksienzyk, Anna K. Wemmer, Klaus Jacobs, Joachim Fossen, Haakon Schomberg, Anna C. Sussenberger, Annette Luensdorf, Nils Keno Bastesen, Eivind |
author_sort |
Ksienzyk, Anna K. |
title |
Post-Caledonian brittle deformation in the Bergen area, West Norway: results from K-Ar illite fault gouge dating |
title_short |
Post-Caledonian brittle deformation in the Bergen area, West Norway: results from K-Ar illite fault gouge dating |
title_full |
Post-Caledonian brittle deformation in the Bergen area, West Norway: results from K-Ar illite fault gouge dating |
title_fullStr |
Post-Caledonian brittle deformation in the Bergen area, West Norway: results from K-Ar illite fault gouge dating |
title_full_unstemmed |
Post-Caledonian brittle deformation in the Bergen area, West Norway: results from K-Ar illite fault gouge dating |
title_sort |
post-caledonian brittle deformation in the bergen area, west norway: results from k-ar illite fault gouge dating |
publisher |
Geological Soc Norway |
publishDate |
2016 |
url |
https://resolver.sub.uni-goettingen.de/purl?gro-2/41721 https://resolver.sub.uni-goettingen.de/purl?gs-1/14300 https://doi.org/10.17850/njg96-3-06 |
geographic |
Norway Bergen |
geographic_facet |
Norway Bergen |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
0029-196X https://resolver.sub.uni-goettingen.de/purl?gro-2/41721 doi:10.17850/njg96-3-06 000390982500006 https://resolver.sub.uni-goettingen.de/purl?gs-1/14300 |
op_rights |
CC BY 4.0 https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.17850/njg96-3-06 |
container_title |
Norwegian Journal of Geology |
_version_ |
1776202331644231680 |