Interpretation of potential field data along the Lofoten continental margin, part I
Aeromagnetic data from the Røst Basin (RAS-03) were acquired in 2003 and compiled with neighbouring data-sets. The new Ra 3 compilation (Røst Aeromagnetics 2003 consisting of LAS-89, NAS-94, VAS-98 and RAS-3) has been reprocessed and subsequently merged with the SPT-93, NGU-69, NGU-73 and NRL-73 sur...
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ftnorgesgu:oai:openarchive.ngu.no:11250/2665055 2023-05-15T16:17:24+02:00 Interpretation of potential field data along the Lofoten continental margin, part I Lundin, Erik Olesen, Odleiv Ebbing, Jörg Skilbrei, Jan Reidar NORDLAND TROMS 2003 application/pdf https://hdl.handle.net/11250/2665055 eng eng NGU-Rapport (2003.089) urn:issn:0800-3416 https://hdl.handle.net/11250/2665055 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no CC-BY 68 KONTINENTALSOKKEL MAGNETOMETRI GRAVIMETRI TOLKNING FORKASTNING GEOFYSIKK BERGGRUNNSGEOLOGI Report 2003 ftnorgesgu 2022-07-03T15:26:15Z Aeromagnetic data from the Røst Basin (RAS-03) were acquired in 2003 and compiled with neighbouring data-sets. The new Ra 3 compilation (Røst Aeromagnetics 2003 consisting of LAS-89, NAS-94, VAS-98 and RAS-3) has been reprocessed and subsequently merged with the SPT-93, NGU-69, NGU-73 and NRL-73 surveys in addition to the mainland of Norway aeromagnetic grid data. A compilation of the existing gravity data in the area has also been carried out. Forward 3D modelling along 14 profiles is constrained by available data on density, magnetic properties and reflection and refraction (OBS) seismics. The new data show that the previously interpreted oceanic fracture zones (Bivrost, Jenegga and Vesterålen) do not exist. Apparent offsets in the oceanic spreading anomalies were caused by poor navigation and wide line spacing of the vintage datasets. Consequently, opening of the Norwegian-Greenland Sea occurred along a stable axis without offsets of the oceanic spreading anomalies. A basement structure map has been compiled, and contains depth to magnetic basement, regional basement faults, and transfer zones. The Sandflesa and Flakstad basement highs at depths of approximately 6 km occur to the southwest and west of the Utrøst Ridge. The Bivrost, Vesterålen and Lenvik transfer zones define the regional segmentation of the Lofoten margin. The local Mosken and Melbu transfer zones are also located where shifts in polarity occur along faults and separate individual rotated fault blocks. The transfer zones are not spatially connected to younger oceanic fracture zones as previously interpreted. Depths to magnetic basement are locally larger than the depths obtained from gravity and seismic data (e.g. in the Helgeland and Vestfjorden basins and the Nordland Ridge). We interpret these to represent down-faulted Caledonian nappes, Devonian sediments or low-magnetic (amphibolite facies) Precambrian rocks. Voluminous mafic intrusions occur in both the basement and the overlying sediments in the Sandflesa high area and cause large ... Report Flakstad Greenland Greenland Sea Helgeland Lenvik Lofoten Nordland Nordland Røst Vesterålen Vestfjorden Nordland Troms NGU Open Archive (Geological Survey of Norway) Greenland Helgeland Lenvik ENVELOPE(17.987,17.987,69.231,69.231) Lofoten Mosken ENVELOPE(12.755,12.755,67.746,67.746) Norway Røst ENVELOPE(11.983,11.983,67.467,67.467) Sandflesa ENVELOPE(8.256,8.256,63.475,63.475) Vesterålen ENVELOPE(14.939,14.939,68.754,68.754) |
institution |
Open Polar |
collection |
NGU Open Archive (Geological Survey of Norway) |
op_collection_id |
ftnorgesgu |
language |
English |
topic |
KONTINENTALSOKKEL MAGNETOMETRI GRAVIMETRI TOLKNING FORKASTNING GEOFYSIKK BERGGRUNNSGEOLOGI |
spellingShingle |
KONTINENTALSOKKEL MAGNETOMETRI GRAVIMETRI TOLKNING FORKASTNING GEOFYSIKK BERGGRUNNSGEOLOGI Lundin, Erik Olesen, Odleiv Ebbing, Jörg Skilbrei, Jan Reidar Interpretation of potential field data along the Lofoten continental margin, part I |
topic_facet |
KONTINENTALSOKKEL MAGNETOMETRI GRAVIMETRI TOLKNING FORKASTNING GEOFYSIKK BERGGRUNNSGEOLOGI |
description |
Aeromagnetic data from the Røst Basin (RAS-03) were acquired in 2003 and compiled with neighbouring data-sets. The new Ra 3 compilation (Røst Aeromagnetics 2003 consisting of LAS-89, NAS-94, VAS-98 and RAS-3) has been reprocessed and subsequently merged with the SPT-93, NGU-69, NGU-73 and NRL-73 surveys in addition to the mainland of Norway aeromagnetic grid data. A compilation of the existing gravity data in the area has also been carried out. Forward 3D modelling along 14 profiles is constrained by available data on density, magnetic properties and reflection and refraction (OBS) seismics. The new data show that the previously interpreted oceanic fracture zones (Bivrost, Jenegga and Vesterålen) do not exist. Apparent offsets in the oceanic spreading anomalies were caused by poor navigation and wide line spacing of the vintage datasets. Consequently, opening of the Norwegian-Greenland Sea occurred along a stable axis without offsets of the oceanic spreading anomalies. A basement structure map has been compiled, and contains depth to magnetic basement, regional basement faults, and transfer zones. The Sandflesa and Flakstad basement highs at depths of approximately 6 km occur to the southwest and west of the Utrøst Ridge. The Bivrost, Vesterålen and Lenvik transfer zones define the regional segmentation of the Lofoten margin. The local Mosken and Melbu transfer zones are also located where shifts in polarity occur along faults and separate individual rotated fault blocks. The transfer zones are not spatially connected to younger oceanic fracture zones as previously interpreted. Depths to magnetic basement are locally larger than the depths obtained from gravity and seismic data (e.g. in the Helgeland and Vestfjorden basins and the Nordland Ridge). We interpret these to represent down-faulted Caledonian nappes, Devonian sediments or low-magnetic (amphibolite facies) Precambrian rocks. Voluminous mafic intrusions occur in both the basement and the overlying sediments in the Sandflesa high area and cause large ... |
format |
Report |
author |
Lundin, Erik Olesen, Odleiv Ebbing, Jörg Skilbrei, Jan Reidar |
author_facet |
Lundin, Erik Olesen, Odleiv Ebbing, Jörg Skilbrei, Jan Reidar |
author_sort |
Lundin, Erik |
title |
Interpretation of potential field data along the Lofoten continental margin, part I |
title_short |
Interpretation of potential field data along the Lofoten continental margin, part I |
title_full |
Interpretation of potential field data along the Lofoten continental margin, part I |
title_fullStr |
Interpretation of potential field data along the Lofoten continental margin, part I |
title_full_unstemmed |
Interpretation of potential field data along the Lofoten continental margin, part I |
title_sort |
interpretation of potential field data along the lofoten continental margin, part i |
publishDate |
2003 |
url |
https://hdl.handle.net/11250/2665055 |
op_coverage |
NORDLAND TROMS |
long_lat |
ENVELOPE(17.987,17.987,69.231,69.231) ENVELOPE(12.755,12.755,67.746,67.746) ENVELOPE(11.983,11.983,67.467,67.467) ENVELOPE(8.256,8.256,63.475,63.475) ENVELOPE(14.939,14.939,68.754,68.754) |
geographic |
Greenland Helgeland Lenvik Lofoten Mosken Norway Røst Sandflesa Vesterålen |
geographic_facet |
Greenland Helgeland Lenvik Lofoten Mosken Norway Røst Sandflesa Vesterålen |
genre |
Flakstad Greenland Greenland Sea Helgeland Lenvik Lofoten Nordland Nordland Røst Vesterålen Vestfjorden Nordland Troms |
genre_facet |
Flakstad Greenland Greenland Sea Helgeland Lenvik Lofoten Nordland Nordland Røst Vesterålen Vestfjorden Nordland Troms |
op_source |
68 |
op_relation |
NGU-Rapport (2003.089) urn:issn:0800-3416 https://hdl.handle.net/11250/2665055 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no |
op_rightsnorm |
CC-BY |
_version_ |
1766003249422270464 |