Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS): criteria for accepting palaeomagnetic data
SUMMARY Anisotropy of magnetic susceptibility data obtained from discrete subsamples recovered from two Integrated Ocean Drilling Program sites (Expedition 347 sites M0061 and M0062 in the Baltic Sea) by an Advanced Piston Corer are compared to results obtained on subsamples recovered by replicate 6...
Published in: | Geophysical Journal International |
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Online Access: | http://dx.doi.org/10.1093/gji/ggz075 http://academic.oup.com/gji/article-pdf/217/2/1089/32357946/ggz075.pdf |
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croxfordunivpr:10.1093/gji/ggz075 2024-09-15T18:07:27+00:00 Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS): criteria for accepting palaeomagnetic data Snowball, Ian Almqvist, Bjarne Lougheed, Bryan C Wiers, Steffen Obrochta, Stephen Herrero-Bervera, Emilio Swedish Research Council University of Hawaii National Science Foundation 2019 http://dx.doi.org/10.1093/gji/ggz075 http://academic.oup.com/gji/article-pdf/217/2/1089/32357946/ggz075.pdf en eng Oxford University Press (OUP) http://creativecommons.org/licenses/by/4.0/ Geophysical Journal International volume 217, issue 2, page 1089-1107 ISSN 0956-540X 1365-246X journal-article 2019 croxfordunivpr https://doi.org/10.1093/gji/ggz075 2024-07-22T04:26:51Z SUMMARY Anisotropy of magnetic susceptibility data obtained from discrete subsamples recovered from two Integrated Ocean Drilling Program sites (Expedition 347 sites M0061 and M0062 in the Baltic Sea) by an Advanced Piston Corer are compared to results obtained on subsamples recovered by replicate 6-m-long Kullenberg piston cores. Characteristic natural remanence directions were obtained from the total of 1097 subsamples using principal component analyses. The three principal anisotropy axes of subsamples taken from Advanced Piston Core liners align to the subsample axes, with the maximum axis (K1) parallel to the split core surfaces, possibly caused by outwards relaxation of the core-liners after splitting. A second anomalous anisotropy fabric is characterized by steep values of the angular difference between the inclination of the minimum anisotropy axes (K3) and that expected for horizontal bedding (90°). This fabric is confined to the upper 1–2 m of the Kullenberg cores and specific sections of the advanced piston cores, and we attribute it to conical deformation caused by either excessive penetration speeds and downwards dragging of sediment along the edge of the liner or stretching caused by undersampling. By using our data in an example, we present a protocol to accept palaeomagnetic secular variation data that uses (i) a threshold 90-K3 value of 15°, combined with a modelled, locally applicable minimum inclination of 65° and (ii) an A95 cone of confidence based on Fisher statistics applied to virtual geomagnetic pole distributions. Article in Journal/Newspaper Geomagnetic Pole Oxford University Press Geophysical Journal International 217 2 1089 1107 |
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Open Polar |
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Oxford University Press |
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croxfordunivpr |
language |
English |
description |
SUMMARY Anisotropy of magnetic susceptibility data obtained from discrete subsamples recovered from two Integrated Ocean Drilling Program sites (Expedition 347 sites M0061 and M0062 in the Baltic Sea) by an Advanced Piston Corer are compared to results obtained on subsamples recovered by replicate 6-m-long Kullenberg piston cores. Characteristic natural remanence directions were obtained from the total of 1097 subsamples using principal component analyses. The three principal anisotropy axes of subsamples taken from Advanced Piston Core liners align to the subsample axes, with the maximum axis (K1) parallel to the split core surfaces, possibly caused by outwards relaxation of the core-liners after splitting. A second anomalous anisotropy fabric is characterized by steep values of the angular difference between the inclination of the minimum anisotropy axes (K3) and that expected for horizontal bedding (90°). This fabric is confined to the upper 1–2 m of the Kullenberg cores and specific sections of the advanced piston cores, and we attribute it to conical deformation caused by either excessive penetration speeds and downwards dragging of sediment along the edge of the liner or stretching caused by undersampling. By using our data in an example, we present a protocol to accept palaeomagnetic secular variation data that uses (i) a threshold 90-K3 value of 15°, combined with a modelled, locally applicable minimum inclination of 65° and (ii) an A95 cone of confidence based on Fisher statistics applied to virtual geomagnetic pole distributions. |
author2 |
Swedish Research Council University of Hawaii National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Snowball, Ian Almqvist, Bjarne Lougheed, Bryan C Wiers, Steffen Obrochta, Stephen Herrero-Bervera, Emilio |
spellingShingle |
Snowball, Ian Almqvist, Bjarne Lougheed, Bryan C Wiers, Steffen Obrochta, Stephen Herrero-Bervera, Emilio Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS): criteria for accepting palaeomagnetic data |
author_facet |
Snowball, Ian Almqvist, Bjarne Lougheed, Bryan C Wiers, Steffen Obrochta, Stephen Herrero-Bervera, Emilio |
author_sort |
Snowball, Ian |
title |
Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS): criteria for accepting palaeomagnetic data |
title_short |
Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS): criteria for accepting palaeomagnetic data |
title_full |
Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS): criteria for accepting palaeomagnetic data |
title_fullStr |
Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS): criteria for accepting palaeomagnetic data |
title_full_unstemmed |
Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS): criteria for accepting palaeomagnetic data |
title_sort |
coring induced sediment fabrics at iodp expedition 347 sites m0061 and m0062 identified by anisotropy of magnetic susceptibility (ams): criteria for accepting palaeomagnetic data |
publisher |
Oxford University Press (OUP) |
publishDate |
2019 |
url |
http://dx.doi.org/10.1093/gji/ggz075 http://academic.oup.com/gji/article-pdf/217/2/1089/32357946/ggz075.pdf |
genre |
Geomagnetic Pole |
genre_facet |
Geomagnetic Pole |
op_source |
Geophysical Journal International volume 217, issue 2, page 1089-1107 ISSN 0956-540X 1365-246X |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1093/gji/ggz075 |
container_title |
Geophysical Journal International |
container_volume |
217 |
container_issue |
2 |
container_start_page |
1089 |
op_container_end_page |
1107 |
_version_ |
1810444826053705728 |