Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea
The SW Barents Sea margin experienced a pulse of extensional deformation in the Middle–Late Devonian through the Carboniferous, after the Caledonian Orogeny terminated. These events marked the initial stages of formation of major offshore basins such as the Hammerfest and Nordkapp basin...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2018-03-01
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| Series: | Solid Earth |
| Online Access: | https://www.solid-earth.net/9/341/2018/se-9-341-2018.pdf |
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| author | J.-B. P. Koehl J.-B. P. Koehl S. G. Bergh S. G. Bergh T. Henningsen J. I. Faleide J. I. Faleide |
| author_facet | J.-B. P. Koehl J.-B. P. Koehl S. G. Bergh S. G. Bergh T. Henningsen J. I. Faleide J. I. Faleide |
| author_sort | J.-B. P. Koehl |
| collection | DOAJ |
| description | The SW Barents Sea margin experienced a pulse of extensional deformation in the
Middle–Late Devonian through the Carboniferous, after the Caledonian Orogeny terminated. These events marked the initial stages of formation of major
offshore basins such as the Hammerfest and Nordkapp
basins. We mapped and analyzed three major fault complexes, (i) the Måsøy Fault Complex, (ii) the Rolvsøya fault, and (iii) the Troms–Finnmark Fault
Complex. We discuss the formation of the Måsøy Fault Complex as a possible extensional splay of an overall NE–SW-trending, NW-dipping, basement-seated Caledonian shear zone, the Sørøya–Ingøya shear zone, which was partly inverted during the collapse of the Caledonides and accommodated top–NW normal displacement in Middle to Late Devonian–Carboniferous times. The Troms–Finnmark Fault Complex displays a zigzag-shaped pattern of NNE–SSW- and ENE–WSW-trending extensional faults before it terminates to the north as a WNW–ESE-trending, NE-dipping normal fault that separates the southwesternmost Nordkapp basin in the northeast from the western Finnmark Platform and the Gjesvær Low in the southwest. The WNW–ESE-trending, margin-oblique segment of the Troms–Finnmark Fault Complex is considered to represent the offshore prolongation of a major Neoproterozoic fault complex, the Trollfjorden–Komagelva Fault Zone, which is made of WNW–ESE-trending, subvertical faults that crop out on the island of Magerøya in NW Finnmark. Our results suggest that the Trollfjorden–Komagelva Fault Zone dies out to the northwest before reaching the western Finnmark Platform. We propose an alternative model for the origin of the WNW–ESE-trending
segment of the Troms–Finnmark Fault Complex as a possible hard-linked,
accommodation cross fault that developed along the
Sørøy–Ingøya shear zone.
This brittle fault decoupled the western Finnmark Platform from the
southwesternmost Nordkapp basin and merged with the Måsøy Fault
Complex in Carboniferous times. Seismic data over the Gjesvær Low and
southwesternmost Nordkapp basin show that the low-gravity anomaly observed in
these areas may result from the presence of Middle to
Upper Devonian sedimentary units resembling those in Middle Devonian,
spoon-shaped, late- to post-orogenic collapse basins in western and
mid-Norway. We propose a model for the formation of the southwesternmost
Nordkapp basin and its counterpart Devonian basin in the Gjesvær Low by
exhumation of narrow, ENE–WSW- to NE–SW-trending basement ridges along a
bowed portion of the Sørøya-Ingøya shear zone in the Middle to Late
Devonian–early Carboniferous. Exhumation may have involved part of a
large-scale metamorphic core complex that potentially included the Lofoten
Ridge, the West Troms Basement Complex and the Norsel High. Finally, we argue
that the Sørøya–Ingøya shear zone truncated and decapitated the
Trollfjorden–Komagelva Fault Zone during the Caledonian Orogeny and that the
western continuation of the Trollfjorden–Komagelva Fault Zone was mostly
eroded and potentially partly preserved in basement highs in the SW Barents
Sea. |
| first_indexed | 2024-04-12T05:30:02Z |
| format | Article |
| id | doaj.art-4de3fb23792740aebe042693a92ea128 |
| institution | Directory Open Access Journal |
| issn | 1869-9510 1869-9529 |
| language | English |
| last_indexed | 2024-04-12T05:30:02Z |
| publishDate | 2018-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Solid Earth |
| spelling | doaj.art-4de3fb23792740aebe042693a92ea1282022-12-22T03:46:06ZengCopernicus PublicationsSolid Earth1869-95101869-95292018-03-01934137210.5194/se-9-341-2018Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents SeaJ.-B. P. Koehl0J.-B. P. Koehl1S. G. Bergh2S. G. Bergh3T. Henningsen4J. I. Faleide5J. I. Faleide6Department of Geosciences, UiT The Arctic University of Norway in Tromsø, 9037 Tromsø, NorwayResearch Centre for Arctic Petroleum Exploration (ARCEx), UiT The Arctic University of Norway in Tromsø, 9037 Tromsø, NorwayDepartment of Geosciences, UiT The Arctic University of Norway in Tromsø, 9037 Tromsø, NorwayResearch Centre for Arctic Petroleum Exploration (ARCEx), UiT The Arctic University of Norway in Tromsø, 9037 Tromsø, NorwayDepartment of Geosciences, UiT The Arctic University of Norway in Tromsø, 9037 Tromsø, NorwayResearch Centre for Arctic Petroleum Exploration (ARCEx), UiT The Arctic University of Norway in Tromsø, 9037 Tromsø, NorwayDepartment of Geosciences, University of Oslo, P.O. Box 1047 Blindern, 0316 Oslo, NorwayThe SW Barents Sea margin experienced a pulse of extensional deformation in the Middle–Late Devonian through the Carboniferous, after the Caledonian Orogeny terminated. These events marked the initial stages of formation of major offshore basins such as the Hammerfest and Nordkapp basins. We mapped and analyzed three major fault complexes, (i) the Måsøy Fault Complex, (ii) the Rolvsøya fault, and (iii) the Troms–Finnmark Fault Complex. We discuss the formation of the Måsøy Fault Complex as a possible extensional splay of an overall NE–SW-trending, NW-dipping, basement-seated Caledonian shear zone, the Sørøya–Ingøya shear zone, which was partly inverted during the collapse of the Caledonides and accommodated top–NW normal displacement in Middle to Late Devonian–Carboniferous times. The Troms–Finnmark Fault Complex displays a zigzag-shaped pattern of NNE–SSW- and ENE–WSW-trending extensional faults before it terminates to the north as a WNW–ESE-trending, NE-dipping normal fault that separates the southwesternmost Nordkapp basin in the northeast from the western Finnmark Platform and the Gjesvær Low in the southwest. The WNW–ESE-trending, margin-oblique segment of the Troms–Finnmark Fault Complex is considered to represent the offshore prolongation of a major Neoproterozoic fault complex, the Trollfjorden–Komagelva Fault Zone, which is made of WNW–ESE-trending, subvertical faults that crop out on the island of Magerøya in NW Finnmark. Our results suggest that the Trollfjorden–Komagelva Fault Zone dies out to the northwest before reaching the western Finnmark Platform. We propose an alternative model for the origin of the WNW–ESE-trending segment of the Troms–Finnmark Fault Complex as a possible hard-linked, accommodation cross fault that developed along the Sørøy–Ingøya shear zone. This brittle fault decoupled the western Finnmark Platform from the southwesternmost Nordkapp basin and merged with the Måsøy Fault Complex in Carboniferous times. Seismic data over the Gjesvær Low and southwesternmost Nordkapp basin show that the low-gravity anomaly observed in these areas may result from the presence of Middle to Upper Devonian sedimentary units resembling those in Middle Devonian, spoon-shaped, late- to post-orogenic collapse basins in western and mid-Norway. We propose a model for the formation of the southwesternmost Nordkapp basin and its counterpart Devonian basin in the Gjesvær Low by exhumation of narrow, ENE–WSW- to NE–SW-trending basement ridges along a bowed portion of the Sørøya-Ingøya shear zone in the Middle to Late Devonian–early Carboniferous. Exhumation may have involved part of a large-scale metamorphic core complex that potentially included the Lofoten Ridge, the West Troms Basement Complex and the Norsel High. Finally, we argue that the Sørøya–Ingøya shear zone truncated and decapitated the Trollfjorden–Komagelva Fault Zone during the Caledonian Orogeny and that the western continuation of the Trollfjorden–Komagelva Fault Zone was mostly eroded and potentially partly preserved in basement highs in the SW Barents Sea.https://www.solid-earth.net/9/341/2018/se-9-341-2018.pdf |
| spellingShingle | J.-B. P. Koehl J.-B. P. Koehl S. G. Bergh S. G. Bergh T. Henningsen J. I. Faleide J. I. Faleide Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea Solid Earth |
| title | Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea |
| title_full | Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea |
| title_fullStr | Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea |
| title_full_unstemmed | Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea |
| title_short | Middle to Late Devonian–Carboniferous collapse basins on the Finnmark Platform and in the southwesternmost Nordkapp basin, SW Barents Sea |
| title_sort | middle to late devonian ndash carboniferous collapse basins on the finnmark platform and in the southwesternmost nordkapp basin sw barents sea |
| url | https://www.solid-earth.net/9/341/2018/se-9-341-2018.pdf |
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