An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash:Implications for the Greenland ice core timescale
Timescales based on counted annual ice layers underpin the interpretation of late Quaternary rapid climatic oscillations recorded in the Greenland ice cores and their correlation to tropical and Antarctic climate archives. An inherent problem in the annual counted ice layer dating method is the larg...
Published in: | Quaternary Science Reviews |
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Language: | English |
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2022
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Online Access: | https://curis.ku.dk/portal/da/publications/an-astronomically-calibrated-40ar39ar-age-for-the-north-atlantic-z2-ash(42a46f6f-4677-4307-91f0-5e676c08fab9).html https://doi.org/10.1016/j.quascirev.2022.107526 https://curis.ku.dk/ws/files/321278855/1_s2.0_S0277379122001573_main.pdf |
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ftcopenhagenunip:oai:pure.atira.dk:publications/42a46f6f-4677-4307-91f0-5e676c08fab9 2024-06-09T07:40:12+00:00 An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash:Implications for the Greenland ice core timescale Groen, Mirek Storey, Michael 2022 application/pdf https://curis.ku.dk/portal/da/publications/an-astronomically-calibrated-40ar39ar-age-for-the-north-atlantic-z2-ash(42a46f6f-4677-4307-91f0-5e676c08fab9).html https://doi.org/10.1016/j.quascirev.2022.107526 https://curis.ku.dk/ws/files/321278855/1_s2.0_S0277379122001573_main.pdf eng eng info:eu-repo/semantics/openAccess Groen , M & Storey , M 2022 , ' An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash : Implications for the Greenland ice core timescale ' , Quaternary Science Reviews , vol. 293 , 107526 . https://doi.org/10.1016/j.quascirev.2022.107526 Ar/Ar dating GICC05 Iceland volcanism NAAZ II NGRIP Thórsmörk ignimbrite Z2 ash article 2022 ftcopenhagenunip https://doi.org/10.1016/j.quascirev.2022.107526 2024-05-16T11:29:25Z Timescales based on counted annual ice layers underpin the interpretation of late Quaternary rapid climatic oscillations recorded in the Greenland ice cores and their correlation to tropical and Antarctic climate archives. An inherent problem in the annual counted ice layer dating method is the large accumulated age uncertainties for the older part of the Greenland ice core timescale due to so called uncertain annual ice layers. Annual ice layers become thinner with depth due to increased compaction. Thus, the occurrence of uncertain annual layers becomes more frequent, such that by a depth of ∼2150 m (43 ka) in the NGRIP ice core the accumulated uncertainty on the age is > 2%. Radio-isotopic age determination of interbedded volcanic ash layers can provide independent verification of the Greenland counted annual ice layer ages along with the possibility of improved precision for the older part of this important timescale. Here we report an astronomically calibrated Ar40/Ar39 age of 56.14 ± 0.44 ka (2σ) for the widespread North Atlantic Z2 ash forming Icelandic Thórsmörk peralkaline rhyolitic eruption. The Z2 ash is found at a depth of 2359.45 m in the NGRIP ice core and has an annual layer counted age of 55.38 ± 2.37 ka (2σ, b2k). Our radio-isotopic age for the Z2 eruption is > 5 times more precise than the one based on counted annual ice layers and when referenced relative to b2k indicates that the oldest part of the GICC05 timescale is systematically too young by approximately 740 years. We use our Z2 eruption age to calculate refined astronomically calibrated ages for Greenland Interstadials (GI) 11 to 17 which results in reducing the age uncertainties on the majority of these events from the millennial to the centennial level. Our refined ages for GI 11–17 generally show good agreement with the NALPS U–Th stalagmite record that covers this same interval and together these high-precision radio-isotopic timescales provide firmer constraints for testing for synchronicity, or leads and lags between ... Article in Journal/Newspaper Antarc* Antarctic Greenland Greenland ice core Greenland ice cores ice core Iceland NGRIP North Atlantic University of Copenhagen: Research Antarctic Greenland Quaternary Science Reviews 293 107526 |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
topic |
Ar/Ar dating GICC05 Iceland volcanism NAAZ II NGRIP Thórsmörk ignimbrite Z2 ash |
spellingShingle |
Ar/Ar dating GICC05 Iceland volcanism NAAZ II NGRIP Thórsmörk ignimbrite Z2 ash Groen, Mirek Storey, Michael An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash:Implications for the Greenland ice core timescale |
topic_facet |
Ar/Ar dating GICC05 Iceland volcanism NAAZ II NGRIP Thórsmörk ignimbrite Z2 ash |
description |
Timescales based on counted annual ice layers underpin the interpretation of late Quaternary rapid climatic oscillations recorded in the Greenland ice cores and their correlation to tropical and Antarctic climate archives. An inherent problem in the annual counted ice layer dating method is the large accumulated age uncertainties for the older part of the Greenland ice core timescale due to so called uncertain annual ice layers. Annual ice layers become thinner with depth due to increased compaction. Thus, the occurrence of uncertain annual layers becomes more frequent, such that by a depth of ∼2150 m (43 ka) in the NGRIP ice core the accumulated uncertainty on the age is > 2%. Radio-isotopic age determination of interbedded volcanic ash layers can provide independent verification of the Greenland counted annual ice layer ages along with the possibility of improved precision for the older part of this important timescale. Here we report an astronomically calibrated Ar40/Ar39 age of 56.14 ± 0.44 ka (2σ) for the widespread North Atlantic Z2 ash forming Icelandic Thórsmörk peralkaline rhyolitic eruption. The Z2 ash is found at a depth of 2359.45 m in the NGRIP ice core and has an annual layer counted age of 55.38 ± 2.37 ka (2σ, b2k). Our radio-isotopic age for the Z2 eruption is > 5 times more precise than the one based on counted annual ice layers and when referenced relative to b2k indicates that the oldest part of the GICC05 timescale is systematically too young by approximately 740 years. We use our Z2 eruption age to calculate refined astronomically calibrated ages for Greenland Interstadials (GI) 11 to 17 which results in reducing the age uncertainties on the majority of these events from the millennial to the centennial level. Our refined ages for GI 11–17 generally show good agreement with the NALPS U–Th stalagmite record that covers this same interval and together these high-precision radio-isotopic timescales provide firmer constraints for testing for synchronicity, or leads and lags between ... |
format |
Article in Journal/Newspaper |
author |
Groen, Mirek Storey, Michael |
author_facet |
Groen, Mirek Storey, Michael |
author_sort |
Groen, Mirek |
title |
An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash:Implications for the Greenland ice core timescale |
title_short |
An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash:Implications for the Greenland ice core timescale |
title_full |
An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash:Implications for the Greenland ice core timescale |
title_fullStr |
An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash:Implications for the Greenland ice core timescale |
title_full_unstemmed |
An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash:Implications for the Greenland ice core timescale |
title_sort |
astronomically calibrated 40 ar/ 39 ar age for the north atlantic z2 ash:implications for the greenland ice core timescale |
publishDate |
2022 |
url |
https://curis.ku.dk/portal/da/publications/an-astronomically-calibrated-40ar39ar-age-for-the-north-atlantic-z2-ash(42a46f6f-4677-4307-91f0-5e676c08fab9).html https://doi.org/10.1016/j.quascirev.2022.107526 https://curis.ku.dk/ws/files/321278855/1_s2.0_S0277379122001573_main.pdf |
geographic |
Antarctic Greenland |
geographic_facet |
Antarctic Greenland |
genre |
Antarc* Antarctic Greenland Greenland ice core Greenland ice cores ice core Iceland NGRIP North Atlantic |
genre_facet |
Antarc* Antarctic Greenland Greenland ice core Greenland ice cores ice core Iceland NGRIP North Atlantic |
op_source |
Groen , M & Storey , M 2022 , ' An astronomically calibrated 40 Ar/ 39 Ar age for the North Atlantic Z2 Ash : Implications for the Greenland ice core timescale ' , Quaternary Science Reviews , vol. 293 , 107526 . https://doi.org/10.1016/j.quascirev.2022.107526 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.quascirev.2022.107526 |
container_title |
Quaternary Science Reviews |
container_volume |
293 |
container_start_page |
107526 |
_version_ |
1801383665389797376 |