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The ST22 chronology for the Skytrain Ice Rise ice core - Part 2 : An age model to the last interglacial and disturbed deep stratigraphy

Mulvaney, Robert ; Wolff, Eric W. ; Grieman, Mackenzie M. ; Hoffmann, Helene H. ; Humby, Jack D. ; Nehrbass-Ahles, Christoph ; Rhodes, Rachael H. ; Rowell, Isobel F. ; Parrenin, Frédéric and Schmidely, Loïc , et al. (2023) In Climate of the Past 19(4). p.851-864
Abstract

We present an age model for the 651g€¯m deep ice core from Skytrain Ice Rise, situated inland of the Ronne Ice Shelf, Antarctica. The top 2000 years have previously been dated using age markers interpolated through annual layer counting. Below this, we align the Skytrain core to the AICC2012 age model using tie points in the ice and air phase, and we apply the Paleochrono program to obtain the best fit to the tie points and glaciological constraints. In the gas phase, ties are made using methane and, in critical sections, δ18Oair; in the ice phase ties are through 10Be across the Laschamps event and through ice chemistry related to long-range dust transport and deposition. This strategy provides a good outcome to about 108g€¯ka... (More)

We present an age model for the 651g€¯m deep ice core from Skytrain Ice Rise, situated inland of the Ronne Ice Shelf, Antarctica. The top 2000 years have previously been dated using age markers interpolated through annual layer counting. Below this, we align the Skytrain core to the AICC2012 age model using tie points in the ice and air phase, and we apply the Paleochrono program to obtain the best fit to the tie points and glaciological constraints. In the gas phase, ties are made using methane and, in critical sections, δ18Oair; in the ice phase ties are through 10Be across the Laschamps event and through ice chemistry related to long-range dust transport and deposition. This strategy provides a good outcome to about 108g€¯ka (g1/4g€¯605g€¯m). Beyond that there are signs of flow disturbance, with a section of ice probably repeated. Nonetheless values of CH4 and δ18Oair confirm that part of the last interglacial (LIG), from about 117-126g€¯ka (617-627g€¯m), is present and in chronological order. Below this there are clear signs of stratigraphic disturbance, with rapid oscillation of values in both the ice and gas phase at the base of the LIG section, below 628g€¯m. Based on methane values, the warmest part of the LIG and the coldest part of the penultimate glacial are missing from our record. Ice below 631g€¯m appears to be of ageg€¯>g€¯150g€¯ka.

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publishing date
type
Contribution to journal
publication status
published
subject
in
Climate of the Past
volume
19
issue
4
pages
14 pages
publisher
Copernicus GmbH
external identifiers
  • scopus:85158077804
ISSN
1814-9324
DOI
10.5194/cp-19-851-2023
language
English
LU publication?
yes
id
59a39a59-1eb8-4f16-9f9a-a8ca52132889
date added to LUP
2023-08-11 13:02:10
date last changed
2024-05-29 11:17:32
@article{59a39a59-1eb8-4f16-9f9a-a8ca52132889,
  abstract     = {{<p>We present an age model for the 651g€¯m deep ice core from Skytrain Ice Rise, situated inland of the Ronne Ice Shelf, Antarctica. The top 2000 years have previously been dated using age markers interpolated through annual layer counting. Below this, we align the Skytrain core to the AICC2012 age model using tie points in the ice and air phase, and we apply the Paleochrono program to obtain the best fit to the tie points and glaciological constraints. In the gas phase, ties are made using methane and, in critical sections, δ18Oair; in the ice phase ties are through 10Be across the Laschamps event and through ice chemistry related to long-range dust transport and deposition. This strategy provides a good outcome to about 108g€¯ka (g1/4g€¯605g€¯m). Beyond that there are signs of flow disturbance, with a section of ice probably repeated. Nonetheless values of CH4 and δ18Oair confirm that part of the last interglacial (LIG), from about 117-126g€¯ka (617-627g€¯m), is present and in chronological order. Below this there are clear signs of stratigraphic disturbance, with rapid oscillation of values in both the ice and gas phase at the base of the LIG section, below 628g€¯m. Based on methane values, the warmest part of the LIG and the coldest part of the penultimate glacial are missing from our record. Ice below 631g€¯m appears to be of ageg€¯&gt;g€¯150g€¯ka.</p>}},
  author       = {{Mulvaney, Robert and Wolff, Eric W. and Grieman, Mackenzie M. and Hoffmann, Helene H. and Humby, Jack D. and Nehrbass-Ahles, Christoph and Rhodes, Rachael H. and Rowell, Isobel F. and Parrenin, Frédéric and Schmidely, Loïc and Fischer, Hubertus and Stocker, Thomas F. and Christl, Marcus and Muscheler, Raimund and Landais, Amaelle and Prié, Frédéric}},
  issn         = {{1814-9324}},
  language     = {{eng}},
  month        = {{04}},
  number       = {{4}},
  pages        = {{851--864}},
  publisher    = {{Copernicus GmbH}},
  series       = {{Climate of the Past}},
  title        = {{The ST22 chronology for the Skytrain Ice Rise ice core - Part 2 : An age model to the last interglacial and disturbed deep stratigraphy}},
  url          = {{http://dx.doi.org/10.5194/cp-19-851-2023}},
  doi          = {{10.5194/cp-19-851-2023}},
  volume       = {{19}},
  year         = {{2023}},
}