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Geomagnetic dipole moment variations for the last glacial period inferred from cosmogenic radionuclides in Greenland ice cores via disentangling the climate and production signals

Zheng, Minjie LU ; Sturevik-Storm, Anna ; Nilsson, Andreas LU ; Adolphi, Florian LU ; Aldahan, Ala ; Possnert, Göran and Muscheler, Raimund LU (2021) In Quaternary Science Reviews 258.
Abstract

The geomagnetic dipole moment (GDM) modulates the production rates of cosmogenic radionuclides via the shielding of galactic cosmic rays. Therefore, it is possible to use this linkage to reconstruct past changes in the GDM based on cosmogenic radionuclide records from natural archives such as ice cores. Here we present a GDM reconstruction based on 10Be and 36Cl data from two Greenland ice cores from 11.7 ka to 108 ka b2k (before A.D. 2000). We find that the cosmogenic radionuclide records reflect a mixture of climate and production effects that require separation to evaluate the changes in the GDM. To minimize climate-related variations on isotope data, we applied a multi-linear correction method by removing... (More)

The geomagnetic dipole moment (GDM) modulates the production rates of cosmogenic radionuclides via the shielding of galactic cosmic rays. Therefore, it is possible to use this linkage to reconstruct past changes in the GDM based on cosmogenic radionuclide records from natural archives such as ice cores. Here we present a GDM reconstruction based on 10Be and 36Cl data from two Greenland ice cores from 11.7 ka to 108 ka b2k (before A.D. 2000). We find that the cosmogenic radionuclide records reflect a mixture of climate and production effects that require separation to evaluate the changes in the GDM. To minimize climate-related variations on isotope data, we applied a multi-linear correction method by removing common variability between 10Be and 36Cl and climate parameters (accumulation rates, δ18O and ion data) from radionuclide records. The resulting “climate corrected” radionuclide data are converted to GDM using a theoretical production model. Comparison of “climate corrected” radionuclides based GDM reconstructions with independent paleomagnetic-derived GDM records shows a good agreement. Furthermore, the “climate correction” leads to an improved agreement with GDM reconstructions than simply using radionuclide fluxes, lending support to the validity of our correction method to isolate production rate changes from ice core radionuclide records. With this correction method, we can extend the GDM reconstructions based on the cosmogenic radionuclides in ice cores to a period when there is a strong climate signal in the data.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cosmogenic isotopes, Geomagnetic dipole moment reconstruction, Glaciology, Greenland ice cores, Multi-linear correction, Quaternary
in
Quaternary Science Reviews
volume
258
article number
106881
publisher
Elsevier
external identifiers
  • scopus:85102865961
ISSN
0277-3791
DOI
10.1016/j.quascirev.2021.106881
language
English
LU publication?
yes
id
3cc06358-56ea-49fd-9748-dd252be05845
date added to LUP
2021-03-30 13:24:57
date last changed
2021-03-30 13:24:57
@article{3cc06358-56ea-49fd-9748-dd252be05845,
  abstract     = {<p>The geomagnetic dipole moment (GDM) modulates the production rates of cosmogenic radionuclides via the shielding of galactic cosmic rays. Therefore, it is possible to use this linkage to reconstruct past changes in the GDM based on cosmogenic radionuclide records from natural archives such as ice cores. Here we present a GDM reconstruction based on <sup>10</sup>Be and <sup>36</sup>Cl data from two Greenland ice cores from 11.7 ka to 108 ka b2k (before A.D. 2000). We find that the cosmogenic radionuclide records reflect a mixture of climate and production effects that require separation to evaluate the changes in the GDM. To minimize climate-related variations on isotope data, we applied a multi-linear correction method by removing common variability between <sup>10</sup>Be and <sup>36</sup>Cl and climate parameters (accumulation rates, δ<sup>18</sup>O and ion data) from radionuclide records. The resulting “climate corrected” radionuclide data are converted to GDM using a theoretical production model. Comparison of “climate corrected” radionuclides based GDM reconstructions with independent paleomagnetic-derived GDM records shows a good agreement. Furthermore, the “climate correction” leads to an improved agreement with GDM reconstructions than simply using radionuclide fluxes, lending support to the validity of our correction method to isolate production rate changes from ice core radionuclide records. With this correction method, we can extend the GDM reconstructions based on the cosmogenic radionuclides in ice cores to a period when there is a strong climate signal in the data.</p>},
  author       = {Zheng, Minjie and Sturevik-Storm, Anna and Nilsson, Andreas and Adolphi, Florian and Aldahan, Ala and Possnert, Göran and Muscheler, Raimund},
  issn         = {0277-3791},
  language     = {eng},
  publisher    = {Elsevier},
  series       = {Quaternary Science Reviews},
  title        = {Geomagnetic dipole moment variations for the last glacial period inferred from cosmogenic radionuclides in Greenland ice cores via disentangling the climate and production signals},
  url          = {http://dx.doi.org/10.1016/j.quascirev.2021.106881},
  doi          = {10.1016/j.quascirev.2021.106881},
  volume       = {258},
  year         = {2021},
}