Scientific results from the deepened Lopra-1 borehole, Faroe Islands: 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 thec. 6½ km thick basalt succession is also described. The polarity record of the Faroe Islands may now be...
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| Format: | Article |
| Language: | English |
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Geological Survey of Denmark and Greenland
2006-07-01
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| Series: | Geological Survey of Denmark and Greenland Bulletin |
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| Online Access: | http://www.geus.dk/publications/bull/nr9/nr9_p51-65.pdf |
| _version_ | 1818261901327466496 |
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| author | Abrahamsen, Niels |
| author_facet | Abrahamsen, Niels |
| author_sort | Abrahamsen, Niels |
| collection | DOAJ |
| 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 thec. 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 thelower 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 mostPalaeogene 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. |
| first_indexed | 2024-12-12T18:54:35Z |
| format | Article |
| id | doaj.art-d20c0702d63a4ecc9683bfa20f8a90e4 |
| institution | Directory Open Access Journal |
| issn | 1604-8156 |
| language | English |
| last_indexed | 2024-12-12T18:54:35Z |
| publishDate | 2006-07-01 |
| publisher | Geological Survey of Denmark and Greenland |
| record_format | Article |
| series | Geological Survey of Denmark and Greenland Bulletin |
| spelling | doaj.art-d20c0702d63a4ecc9683bfa20f8a90e42022-12-22T00:15:16ZengGeological Survey of Denmark and GreenlandGeological Survey of Denmark and Greenland Bulletin1604-81562006-07-01095165Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe IslandsAbrahamsen, NielsThe 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 thec. 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 thelower 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 mostPalaeogene 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.http://www.geus.dk/publications/bull/nr9/nr9_p51-65.pdfPalaeomagnetismrock magnetismmagnetic reversalsplate tectonicsFaroe IslandsLopra-1/1A wellNorth Atlanticlarge igneous province |
| spellingShingle | Abrahamsen, Niels Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands Geological Survey of Denmark and Greenland Bulletin Palaeomagnetism rock magnetism magnetic reversals plate tectonics Faroe Islands Lopra-1/1A well North Atlantic large igneous province |
| title | Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
| title_full | Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
| title_fullStr | Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
| title_full_unstemmed | Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
| title_short | Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Palaeomagnetic results from the Lopra-1/1A re-entry well, Faroe Islands |
| title_sort | scientific results from the deepened lopra 1 borehole faroe islands palaeomagnetic results from the lopra 1 1a re entry well faroe islands |
| topic | Palaeomagnetism rock magnetism magnetic reversals plate tectonics Faroe Islands Lopra-1/1A well North Atlantic large igneous province |
| url | http://www.geus.dk/publications/bull/nr9/nr9_p51-65.pdf |
| work_keys_str_mv | AT abrahamsenniels scientificresultsfromthedeepenedlopra1boreholefaroeislandspalaeomagneticresultsfromthelopra11areentrywellfaroeislands |