Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland
We have reconstructed chronology for the disturbed bottom parts of the GRIP and GISP2 ice cores using the combined paleoatmospheric records of CH₄ concentration and δ¹⁸O[subscript atm] in the trapped gases. Our reconstructed ages for basal ice samples are based on comparison of published measurement...
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ftoregonstate:ir.library.oregonstate.edu:8g84mr653 2024-09-15T18:09:35+00:00 Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland Suwa, Makoto von Fischer, Joseph C. Bender, Michael L. Landais, Amaelle Brook, Edward J. Geosciences https://ir.library.oregonstate.edu/concern/articles/8g84mr653 English [eng] eng unknown American Geophysical Union https://ir.library.oregonstate.edu/concern/articles/8g84mr653 In Copyright Article ftoregonstate 2024-07-22T18:06:06Z We have reconstructed chronology for the disturbed bottom parts of the GRIP and GISP2 ice cores using the combined paleoatmospheric records of CH₄ concentration and δ¹⁸O[subscript atm] in the trapped gases. Our reconstructed ages for basal ice samples are based on comparison of published measurements of CH₄ and δ¹⁸O[subscript atm] from the disturbed section of the GRIP and GISP2 cores with the same properties in the Vostok ice core. NGRIP δ¹⁸O[subscript ice] values are also used to constrain the chronology during the end of marine isotope stage 5e. For each sample, we assign an age that represents the unique or most probable time of gas trapping, given its gas composition. Of 157 samples with CH₄ and δ¹⁸O[subscript atm] data, 10 give unique ages. Twenty-five newly measured values of the triple isotope composition of O₂ from the disturbed section of the GISP2 core add a third time-dependent gas property that agrees with our reconstruction. Our reconstruction supports earlier conclusions of Landais et al. (2003) that the disturbed section primarily includes ice from the last interglacial (MIS 5e) and the penultimate glacial period (MIS 6). The oldest ice in the basal layer of GISP2 and GRIP has an age ≥237 ka. The climate history we derive suggests that the last interglacial at Summit, Greenland, around 127 ka was slightly warmer than the current interglacial period. Reduction of various ion concentrations in ice and thickening of the ice sheet during Termination II was similar to that in Termination I. Keywords: chronology, Termination II, ice core Article in Journal/Newspaper Greenland GRIP ice core Ice Sheet NGRIP ScholarsArchive@OSU (Oregon State University) |
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Open Polar |
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ScholarsArchive@OSU (Oregon State University) |
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ftoregonstate |
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English unknown |
description |
We have reconstructed chronology for the disturbed bottom parts of the GRIP and GISP2 ice cores using the combined paleoatmospheric records of CH₄ concentration and δ¹⁸O[subscript atm] in the trapped gases. Our reconstructed ages for basal ice samples are based on comparison of published measurements of CH₄ and δ¹⁸O[subscript atm] from the disturbed section of the GRIP and GISP2 cores with the same properties in the Vostok ice core. NGRIP δ¹⁸O[subscript ice] values are also used to constrain the chronology during the end of marine isotope stage 5e. For each sample, we assign an age that represents the unique or most probable time of gas trapping, given its gas composition. Of 157 samples with CH₄ and δ¹⁸O[subscript atm] data, 10 give unique ages. Twenty-five newly measured values of the triple isotope composition of O₂ from the disturbed section of the GISP2 core add a third time-dependent gas property that agrees with our reconstruction. Our reconstruction supports earlier conclusions of Landais et al. (2003) that the disturbed section primarily includes ice from the last interglacial (MIS 5e) and the penultimate glacial period (MIS 6). The oldest ice in the basal layer of GISP2 and GRIP has an age ≥237 ka. The climate history we derive suggests that the last interglacial at Summit, Greenland, around 127 ka was slightly warmer than the current interglacial period. Reduction of various ion concentrations in ice and thickening of the ice sheet during Termination II was similar to that in Termination I. Keywords: chronology, Termination II, ice core |
author2 |
Geosciences |
format |
Article in Journal/Newspaper |
author |
Suwa, Makoto von Fischer, Joseph C. Bender, Michael L. Landais, Amaelle Brook, Edward J. |
spellingShingle |
Suwa, Makoto von Fischer, Joseph C. Bender, Michael L. Landais, Amaelle Brook, Edward J. Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland |
author_facet |
Suwa, Makoto von Fischer, Joseph C. Bender, Michael L. Landais, Amaelle Brook, Edward J. |
author_sort |
Suwa, Makoto |
title |
Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland |
title_short |
Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland |
title_full |
Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland |
title_fullStr |
Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland |
title_full_unstemmed |
Chronology reconstruction for the disturbed bottom section of the GISP2 and the GRIP ice cores: Implications for Termination II in Greenland |
title_sort |
chronology reconstruction for the disturbed bottom section of the gisp2 and the grip ice cores: implications for termination ii in greenland |
publisher |
American Geophysical Union |
url |
https://ir.library.oregonstate.edu/concern/articles/8g84mr653 |
genre |
Greenland GRIP ice core Ice Sheet NGRIP |
genre_facet |
Greenland GRIP ice core Ice Sheet NGRIP |
op_relation |
https://ir.library.oregonstate.edu/concern/articles/8g84mr653 |
op_rights |
In Copyright |
_version_ |
1810447155752599552 |