Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands
The palaeomagnetic dating and evolution of the Faroe Islands are discussed in the context of new density and rock magnetic results from the deepened Lopra-1/1A well. The reversal chronology of the c. 6½ km thick basalt succession is also described. The polarity record of the Faroe Islands may now be...
Published in: | Geological Survey of Denmark and Greenland (GEUS) Bulletin |
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Geological Survey of Denmark and Greenland (GEUS)
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Online Access: | https://geusbulletin.org/index.php/geusb/article/view/4859 https://doi.org/10.34194/geusb.v9.4859 |
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ftjgeusbullet:oai:geusjournals.org:article/4859 2023-05-15T16:10:32+02:00 Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands Abrahamsen, Niels 2006-05-31 application/pdf https://geusbulletin.org/index.php/geusb/article/view/4859 https://doi.org/10.34194/geusb.v9.4859 eng eng Geological Survey of Denmark and Greenland (GEUS) https://geusbulletin.org/index.php/geusb/article/view/4859/10492 https://geusbulletin.org/index.php/geusb/article/view/4859 doi:10.34194/geusb.v9.4859 GEUS Bulletin; Vol. 9 (2006): Scientific results from the deepened Lopra-1 borehole, Faroe Islands; 51-65 2597-2154 2597-2162 Palaeomagnetism rock magnetism magnetic reversals plate tectonics Faroe Islands Lopra-1/1A well North Atlantic large igneous province info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article. 2006 ftjgeusbullet https://doi.org/10.34194/geusb.v9.4859 2022-03-15T17:22:19Z The palaeomagnetic dating and evolution of the Faroe Islands are discussed in the context of new density and rock magnetic results from the deepened Lopra-1/1A well. The reversal chronology of the c. 6½ km thick basalt succession is also described. The polarity record of the Faroe Islands may now be correlated in detail with the Geomagnetic Polarity Time Scale. The lowermost (hidden) part of the lower basalt formation correlates with Chron C26r (Selandian age), the top (exposed) part of the lower basalt formation correlates with Chrons C26n, C25r and C25n (Selandian and Thanetian age) and the middle and upper basalt formations correlate with Chron C24n.3r (Ypresian). Inclinations indicate a far-sided position of the palaeomagnetic poles, which is characteristic of results from most Palaeogene volcanics from the northern North Atlantic region. The density, magnetic susceptibility and magnetic remanence of 20 specimens from one solid core (1½ m in length) and 26 sidewall cores from the well between –2219 and –3531 m below sea level (b.s.l.) suggest that the volcanic materials can be divided into two characteristic groups: solid unaltered basalts and altered basalts and tuffs. The magnetic properties are typically log-normally distributed and the carriers of remanence are Ti-poor Ti-magnetites with Curie temperatures close to 580°C. The inclination of the 1½ m core at 2380 m b.s.l. is dominantly negative (two plugs at the very top of the core do show normal polarity, but they are likely to be misoriented as all specimens appear to be from one flow). Magnetic logging (magnetic susceptibility and field intensity) down to 3515 m b.s.l. was made in Lopra-1/1A together with other geophysical logs but did not yield conclusive inclination data. Article in Journal/Newspaper Faroe Islands North Atlantic GEUS Bulletin (Geological Survey of Denmark and Greenland) Faroe Islands Lopra ENVELOPE(-6.771,-6.771,61.444,61.444) Geological Survey of Denmark and Greenland (GEUS) Bulletin 9 51 65 |
institution |
Open Polar |
collection |
GEUS Bulletin (Geological Survey of Denmark and Greenland) |
op_collection_id |
ftjgeusbullet |
language |
English |
topic |
Palaeomagnetism rock magnetism magnetic reversals plate tectonics Faroe Islands Lopra-1/1A well North Atlantic large igneous province |
spellingShingle |
Palaeomagnetism rock magnetism magnetic reversals plate tectonics Faroe Islands Lopra-1/1A well North Atlantic large igneous province Abrahamsen, Niels Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
topic_facet |
Palaeomagnetism rock magnetism magnetic reversals plate tectonics Faroe Islands Lopra-1/1A well North Atlantic large igneous province |
description |
The palaeomagnetic dating and evolution of the Faroe Islands are discussed in the context of new density and rock magnetic results from the deepened Lopra-1/1A well. The reversal chronology of the c. 6½ km thick basalt succession is also described. The polarity record of the Faroe Islands may now be correlated in detail with the Geomagnetic Polarity Time Scale. The lowermost (hidden) part of the lower basalt formation correlates with Chron C26r (Selandian age), the top (exposed) part of the lower basalt formation correlates with Chrons C26n, C25r and C25n (Selandian and Thanetian age) and the middle and upper basalt formations correlate with Chron C24n.3r (Ypresian). Inclinations indicate a far-sided position of the palaeomagnetic poles, which is characteristic of results from most Palaeogene volcanics from the northern North Atlantic region. The density, magnetic susceptibility and magnetic remanence of 20 specimens from one solid core (1½ m in length) and 26 sidewall cores from the well between –2219 and –3531 m below sea level (b.s.l.) suggest that the volcanic materials can be divided into two characteristic groups: solid unaltered basalts and altered basalts and tuffs. The magnetic properties are typically log-normally distributed and the carriers of remanence are Ti-poor Ti-magnetites with Curie temperatures close to 580°C. The inclination of the 1½ m core at 2380 m b.s.l. is dominantly negative (two plugs at the very top of the core do show normal polarity, but they are likely to be misoriented as all specimens appear to be from one flow). Magnetic logging (magnetic susceptibility and field intensity) down to 3515 m b.s.l. was made in Lopra-1/1A together with other geophysical logs but did not yield conclusive inclination data. |
format |
Article in Journal/Newspaper |
author |
Abrahamsen, Niels |
author_facet |
Abrahamsen, Niels |
author_sort |
Abrahamsen, Niels |
title |
Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
title_short |
Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
title_full |
Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
title_fullStr |
Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
title_full_unstemmed |
Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
title_sort |
palaeomagnetic results from the lopra-1/1a re-entry well, faroe islands |
publisher |
Geological Survey of Denmark and Greenland (GEUS) |
publishDate |
2006 |
url |
https://geusbulletin.org/index.php/geusb/article/view/4859 https://doi.org/10.34194/geusb.v9.4859 |
long_lat |
ENVELOPE(-6.771,-6.771,61.444,61.444) |
geographic |
Faroe Islands Lopra |
geographic_facet |
Faroe Islands Lopra |
genre |
Faroe Islands North Atlantic |
genre_facet |
Faroe Islands North Atlantic |
op_source |
GEUS Bulletin; Vol. 9 (2006): Scientific results from the deepened Lopra-1 borehole, Faroe Islands; 51-65 2597-2154 2597-2162 |
op_relation |
https://geusbulletin.org/index.php/geusb/article/view/4859/10492 https://geusbulletin.org/index.php/geusb/article/view/4859 doi:10.34194/geusb.v9.4859 |
op_doi |
https://doi.org/10.34194/geusb.v9.4859 |
container_title |
Geological Survey of Denmark and Greenland (GEUS) Bulletin |
container_volume |
9 |
container_start_page |
51 |
op_container_end_page |
65 |
_version_ |
1765995716644175872 |