Assessing the reliability of Holocene relative palaeointensity estimates: a case study from Swedish varved lake sediments
We present palaeomagnetic secular variation and relative palaeointensity estimates from multiple sediment cores recovered from a varved lake sediment sequence in Kalksjon, a lake in central west Sweden. Alternating field demagnetization of discrete samples reveals natural remanent magnetizations dom...
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Oxford University Press
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Online Access: | https://lup.lub.lu.se/record/2239710 https://doi.org/10.1111/j.1365-246X.2011.05049.x |
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ftulundlup:oai:lup.lub.lu.se:eed73ed9-fd93-4dd0-bdc0-3b9cef986037 2023-05-15T16:13:08+02:00 Assessing the reliability of Holocene relative palaeointensity estimates: a case study from Swedish varved lake sediments Stanton, Tania Nilsson, Andreas Snowball, Ian Muscheler, Raimund 2011 https://lup.lub.lu.se/record/2239710 https://doi.org/10.1111/j.1365-246X.2011.05049.x eng eng Oxford University Press https://lup.lub.lu.se/record/2239710 http://dx.doi.org/10.1111/j.1365-246X.2011.05049.x wos:000297114400010 scopus:81755173465 Geophysical Journal International; 187(3), pp 1195-1214 (2011) ISSN: 0956-540X Geology Environmental magnetism Magnetic field Palaeointensity Palaeomagnetic secular variation Rock and mineral magnetism Europe contributiontojournal/article info:eu-repo/semantics/article text 2011 ftulundlup https://doi.org/10.1111/j.1365-246X.2011.05049.x 2023-02-01T23:29:05Z We present palaeomagnetic secular variation and relative palaeointensity estimates from multiple sediment cores recovered from a varved lake sediment sequence in Kalksjon, a lake in central west Sweden. Alternating field demagnetization of discrete samples reveals natural remanent magnetizations dominated by a stable, single component. Magnetic grain size indicators-which include Day plots and first-order reversal curves-indicate that the main carrier of the natural remanence is single-domain magnetite throughout the varved sequence, which extends to similar to 9200 cal. yr BP. The millennial-scale features of the Kalksjon relative palaeointensity, inclination and declination data are well matched against the Fennoscandian master curves FENNORPIS and FENNOSTACK, and a global dipole moment reconstruction curve. There is evidence, however, of environmental bias in the relative palaeointensity estimates during specific time intervals. We find that bias is particularly pronounced during the early Holocene, specifically between similar to 9000 and 7800 cal. yr BP. During this period the bias is apparent as a series of relative palaeointensity cycles, with a wavelength of similar to 300 years. Some bias is also evident between 7800 and 3200 cal. yr BP. By comparing Kalksjon's smoothed relative palaeointensity data with the reconstructed geomagnetic field intensity from C-14 on timescales longer than 500 years-thereby removing the effect of relatively high frequency environmental bias in the early Holocene-we suggest that a distinct peak in intensity at centred on similar to 8700 cal. yr BP is a true feature of the geomagnetic field. A minimum at similar to 7400 cal. yr BP and a maximum at similar to 2500 cal. yr BP are also robust features. Our main conclusion is that sedimentary-based relative palaeointensity reconstructions must be carefully assessed if short-term, centennial variations are to be examined. Article in Journal/Newspaper Fennoscandian Lund University Publications (LUP) Geophysical Journal International 187 3 1195 1214 |
institution |
Open Polar |
collection |
Lund University Publications (LUP) |
op_collection_id |
ftulundlup |
language |
English |
topic |
Geology Environmental magnetism Magnetic field Palaeointensity Palaeomagnetic secular variation Rock and mineral magnetism Europe |
spellingShingle |
Geology Environmental magnetism Magnetic field Palaeointensity Palaeomagnetic secular variation Rock and mineral magnetism Europe Stanton, Tania Nilsson, Andreas Snowball, Ian Muscheler, Raimund Assessing the reliability of Holocene relative palaeointensity estimates: a case study from Swedish varved lake sediments |
topic_facet |
Geology Environmental magnetism Magnetic field Palaeointensity Palaeomagnetic secular variation Rock and mineral magnetism Europe |
description |
We present palaeomagnetic secular variation and relative palaeointensity estimates from multiple sediment cores recovered from a varved lake sediment sequence in Kalksjon, a lake in central west Sweden. Alternating field demagnetization of discrete samples reveals natural remanent magnetizations dominated by a stable, single component. Magnetic grain size indicators-which include Day plots and first-order reversal curves-indicate that the main carrier of the natural remanence is single-domain magnetite throughout the varved sequence, which extends to similar to 9200 cal. yr BP. The millennial-scale features of the Kalksjon relative palaeointensity, inclination and declination data are well matched against the Fennoscandian master curves FENNORPIS and FENNOSTACK, and a global dipole moment reconstruction curve. There is evidence, however, of environmental bias in the relative palaeointensity estimates during specific time intervals. We find that bias is particularly pronounced during the early Holocene, specifically between similar to 9000 and 7800 cal. yr BP. During this period the bias is apparent as a series of relative palaeointensity cycles, with a wavelength of similar to 300 years. Some bias is also evident between 7800 and 3200 cal. yr BP. By comparing Kalksjon's smoothed relative palaeointensity data with the reconstructed geomagnetic field intensity from C-14 on timescales longer than 500 years-thereby removing the effect of relatively high frequency environmental bias in the early Holocene-we suggest that a distinct peak in intensity at centred on similar to 8700 cal. yr BP is a true feature of the geomagnetic field. A minimum at similar to 7400 cal. yr BP and a maximum at similar to 2500 cal. yr BP are also robust features. Our main conclusion is that sedimentary-based relative palaeointensity reconstructions must be carefully assessed if short-term, centennial variations are to be examined. |
format |
Article in Journal/Newspaper |
author |
Stanton, Tania Nilsson, Andreas Snowball, Ian Muscheler, Raimund |
author_facet |
Stanton, Tania Nilsson, Andreas Snowball, Ian Muscheler, Raimund |
author_sort |
Stanton, Tania |
title |
Assessing the reliability of Holocene relative palaeointensity estimates: a case study from Swedish varved lake sediments |
title_short |
Assessing the reliability of Holocene relative palaeointensity estimates: a case study from Swedish varved lake sediments |
title_full |
Assessing the reliability of Holocene relative palaeointensity estimates: a case study from Swedish varved lake sediments |
title_fullStr |
Assessing the reliability of Holocene relative palaeointensity estimates: a case study from Swedish varved lake sediments |
title_full_unstemmed |
Assessing the reliability of Holocene relative palaeointensity estimates: a case study from Swedish varved lake sediments |
title_sort |
assessing the reliability of holocene relative palaeointensity estimates: a case study from swedish varved lake sediments |
publisher |
Oxford University Press |
publishDate |
2011 |
url |
https://lup.lub.lu.se/record/2239710 https://doi.org/10.1111/j.1365-246X.2011.05049.x |
genre |
Fennoscandian |
genre_facet |
Fennoscandian |
op_source |
Geophysical Journal International; 187(3), pp 1195-1214 (2011) ISSN: 0956-540X |
op_relation |
https://lup.lub.lu.se/record/2239710 http://dx.doi.org/10.1111/j.1365-246X.2011.05049.x wos:000297114400010 scopus:81755173465 |
op_doi |
https://doi.org/10.1111/j.1365-246X.2011.05049.x |
container_title |
Geophysical Journal International |
container_volume |
187 |
container_issue |
3 |
container_start_page |
1195 |
op_container_end_page |
1214 |
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1765998744568856576 |