Evidence from 40 Ar/ 39 Ar Ages of Individual Hornblende Grains for Varying Laurentide Sources of Iceberg Discharges 22,000 to 10,500 yr B.P.
The abundance and lithic content of ice rafted detritus in glacial North Atlantic sediment cores vary abruptly on millennial time scales that have been correlated to Dansgaard-Oeschger cycles in the Greenland ice cores. There is growing evidence that various ice sheet outlets contributed increased i...
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crcambridgeupr:10.1006/qres.2000.2181 2024-09-15T17:57:05+00:00 Evidence from 40 Ar/ 39 Ar Ages of Individual Hornblende Grains for Varying Laurentide Sources of Iceberg Discharges 22,000 to 10,500 yr B.P. Hemming, Sidney R. Bond, Gerard C. Broecker, Wallace S. Sharp, Warren D. Klas-Mendelson, Mieczyslawa 2000 http://dx.doi.org/10.1006/qres.2000.2181 http://api.elsevier.com/content/article/PII:S0033589400921811?httpAccept=text/xml http://api.elsevier.com/content/article/PII:S0033589400921811?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400026466 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Quaternary Research volume 54, issue 3, page 372-383 ISSN 0033-5894 1096-0287 journal-article 2000 crcambridgeupr https://doi.org/10.1006/qres.2000.2181 2024-07-31T04:04:10Z The abundance and lithic content of ice rafted detritus in glacial North Atlantic sediment cores vary abruptly on millennial time scales that have been correlated to Dansgaard-Oeschger cycles in the Greenland ice cores. There is growing evidence that various ice sheet outlets contributed increased iceberg fluxes at multiple discrete intervals, and the relative timing of iceberg discharges from different sources is important for understanding interactions between oceans and ice sheets. We present a provenance study based on 40 Ar/ 39 Ar dates of individual hornblende grains from 20 samples taken at 600 to 700 yr spacing between 10,500 and 22,000 yr B.P., from Orphan Knoll core EW9303-GGC31. Heinrich layers are characterized by a dominant Paleoproterozoic hornblende provenance consistent with published studies. A change in provenance between Heinrich events H2 and H1 indicates contributions of iceberg calving from the Newfoundland and southern Labrador margins. Between H1 and the Younger Dryas interval, Paleoproterozoic ice rafted grains remained dominant. The dominance of Baffin Island (or Greenland?) sources to the ice rafted detritus is ascribed to the retreat of the southern Laurentide ice sheet at about the time of H1—a retreat that isolated Newfoundland and southern Labrador ice from the shelf-slope boundary. Article in Journal/Newspaper Baffin Island Baffin Greenland Greenland ice cores Ice Sheet Newfoundland North Atlantic Cambridge University Press Quaternary Research 54 3 372 383 |
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Cambridge University Press |
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English |
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The abundance and lithic content of ice rafted detritus in glacial North Atlantic sediment cores vary abruptly on millennial time scales that have been correlated to Dansgaard-Oeschger cycles in the Greenland ice cores. There is growing evidence that various ice sheet outlets contributed increased iceberg fluxes at multiple discrete intervals, and the relative timing of iceberg discharges from different sources is important for understanding interactions between oceans and ice sheets. We present a provenance study based on 40 Ar/ 39 Ar dates of individual hornblende grains from 20 samples taken at 600 to 700 yr spacing between 10,500 and 22,000 yr B.P., from Orphan Knoll core EW9303-GGC31. Heinrich layers are characterized by a dominant Paleoproterozoic hornblende provenance consistent with published studies. A change in provenance between Heinrich events H2 and H1 indicates contributions of iceberg calving from the Newfoundland and southern Labrador margins. Between H1 and the Younger Dryas interval, Paleoproterozoic ice rafted grains remained dominant. The dominance of Baffin Island (or Greenland?) sources to the ice rafted detritus is ascribed to the retreat of the southern Laurentide ice sheet at about the time of H1—a retreat that isolated Newfoundland and southern Labrador ice from the shelf-slope boundary. |
format |
Article in Journal/Newspaper |
author |
Hemming, Sidney R. Bond, Gerard C. Broecker, Wallace S. Sharp, Warren D. Klas-Mendelson, Mieczyslawa |
spellingShingle |
Hemming, Sidney R. Bond, Gerard C. Broecker, Wallace S. Sharp, Warren D. Klas-Mendelson, Mieczyslawa Evidence from 40 Ar/ 39 Ar Ages of Individual Hornblende Grains for Varying Laurentide Sources of Iceberg Discharges 22,000 to 10,500 yr B.P. |
author_facet |
Hemming, Sidney R. Bond, Gerard C. Broecker, Wallace S. Sharp, Warren D. Klas-Mendelson, Mieczyslawa |
author_sort |
Hemming, Sidney R. |
title |
Evidence from 40 Ar/ 39 Ar Ages of Individual Hornblende Grains for Varying Laurentide Sources of Iceberg Discharges 22,000 to 10,500 yr B.P. |
title_short |
Evidence from 40 Ar/ 39 Ar Ages of Individual Hornblende Grains for Varying Laurentide Sources of Iceberg Discharges 22,000 to 10,500 yr B.P. |
title_full |
Evidence from 40 Ar/ 39 Ar Ages of Individual Hornblende Grains for Varying Laurentide Sources of Iceberg Discharges 22,000 to 10,500 yr B.P. |
title_fullStr |
Evidence from 40 Ar/ 39 Ar Ages of Individual Hornblende Grains for Varying Laurentide Sources of Iceberg Discharges 22,000 to 10,500 yr B.P. |
title_full_unstemmed |
Evidence from 40 Ar/ 39 Ar Ages of Individual Hornblende Grains for Varying Laurentide Sources of Iceberg Discharges 22,000 to 10,500 yr B.P. |
title_sort |
evidence from 40 ar/ 39 ar ages of individual hornblende grains for varying laurentide sources of iceberg discharges 22,000 to 10,500 yr b.p. |
publisher |
Cambridge University Press (CUP) |
publishDate |
2000 |
url |
http://dx.doi.org/10.1006/qres.2000.2181 http://api.elsevier.com/content/article/PII:S0033589400921811?httpAccept=text/xml http://api.elsevier.com/content/article/PII:S0033589400921811?httpAccept=text/plain https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400026466 |
genre |
Baffin Island Baffin Greenland Greenland ice cores Ice Sheet Newfoundland North Atlantic |
genre_facet |
Baffin Island Baffin Greenland Greenland ice cores Ice Sheet Newfoundland North Atlantic |
op_source |
Quaternary Research volume 54, issue 3, page 372-383 ISSN 0033-5894 1096-0287 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1006/qres.2000.2181 |
container_title |
Quaternary Research |
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54 |
container_issue |
3 |
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372 |
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383 |
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1810433271353311232 |