Coring induced sediment fabrics at IODP Expedition 347 Sites M0061 and M0062 identified by anisotropy of magnetic susceptibility (AMS) : criteria for accepting palaeomagnetic data
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...
Published in: | Geophysical Journal International |
---|---|
Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Uppsala universitet, Naturresurser och hållbar utveckling
2019
|
Subjects: | |
Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-376592 https://doi.org/10.1093/gji/ggz075 |
id |
ftuppsalauniv:oai:DiVA.org:uu-376592 |
---|---|
record_format |
openpolar |
spelling |
ftuppsalauniv:oai:DiVA.org:uu-376592 2023-05-15T16:19:40+02:00 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 2019 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-376592 https://doi.org/10.1093/gji/ggz075 eng eng Uppsala universitet, Naturresurser och hållbar utveckling Uppsala universitet, Geofysik Geophysical Journal International, 0956-540X, 2019, 217:2, s. 1089-1107 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-376592 doi:10.1093/gji/ggz075 ISI:000465608000024 info:eu-repo/semantics/openAccess Magnetic fabrics and anisotropy Palaeomagnetic secular variation Palaeomagnetism Geology Geologi Article in journal info:eu-repo/semantics/article text 2019 ftuppsalauniv https://doi.org/10.1093/gji/ggz075 2023-02-23T21:51:23Z 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. This article has been accepted for publication in Geophysical Journal International ©: 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Article in Journal/Newspaper Geomagnetic Pole Uppsala University: Publications (DiVA) Geophysical Journal International 217 2 1089 1107 |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Magnetic fabrics and anisotropy Palaeomagnetic secular variation Palaeomagnetism Geology Geologi |
spellingShingle |
Magnetic fabrics and anisotropy Palaeomagnetic secular variation Palaeomagnetism Geology Geologi 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 |
topic_facet |
Magnetic fabrics and anisotropy Palaeomagnetic secular variation Palaeomagnetism Geology Geologi |
description |
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. This article has been accepted for publication in Geophysical Journal International ©: 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
format |
Article in Journal/Newspaper |
author |
Snowball, Ian Almqvist, Bjarne Lougheed, Bryan C. Wiers, Steffen Obrochta, Stephen Herrero-Bervera, Emilio |
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 |
Uppsala universitet, Naturresurser och hållbar utveckling |
publishDate |
2019 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-376592 https://doi.org/10.1093/gji/ggz075 |
genre |
Geomagnetic Pole |
genre_facet |
Geomagnetic Pole |
op_relation |
Geophysical Journal International, 0956-540X, 2019, 217:2, s. 1089-1107 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-376592 doi:10.1093/gji/ggz075 ISI:000465608000024 |
op_rights |
info:eu-repo/semantics/openAccess |
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_ |
1766006086253412352 |