Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas
We present a new speleothem record of atmospheric Δ14C between 28 and 44 ka that offers considerable promise for resolving some of the uncertainty associated with existing radiocarbon calibration curves for this time period. The record is based on a comprehensive suite of AMS 14C ages, using new low...
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ftunivreading:oai:centaur.reading.ac.uk:34558 2024-09-15T18:10:03+00:00 Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas Hoffmann, Dirk L. Beck, J. Warren Richards, David A. Smart, Peter L. Singarayer, Joy S. Ketchmark, Tricia Hawkesworth, Chris J. 2010 https://centaur.reading.ac.uk/34558/ https://doi.org/10.1016/j.epsl.2009.10.004 unknown Elsevier Hoffmann, D. L., Beck, J. W., Richards, D. A., Smart, P. L., Singarayer, J. S. <https://centaur.reading.ac.uk/view/creators/90005422.html>, Ketchmark, T. and Hawkesworth, C. J. (2010) Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas. Earth and Planetary Science Letters, 289 (1-2). pp. 1-10. ISSN 0012-821X doi: https://doi.org/10.1016/j.epsl.2009.10.004 <https://doi.org/10.1016/j.epsl.2009.10.004> Article PeerReviewed 2010 ftunivreading https://doi.org/10.1016/j.epsl.2009.10.004 2024-06-25T14:55:27Z We present a new speleothem record of atmospheric Δ14C between 28 and 44 ka that offers considerable promise for resolving some of the uncertainty associated with existing radiocarbon calibration curves for this time period. The record is based on a comprehensive suite of AMS 14C ages, using new low-blank protocols, and U–Th ages using high precision MC-ICPMS procedures. Atmospheric Δ14C was calculated by correcting 14C ages with a constant dead carbon fraction (DCF) of 22.7 ± 5.9%, based on a comparison of stalagmite 14C ages with the IntCal04 (Reimer et al., 2004) calibration curve between 15 and 11 ka. The new Δ14C speleothem record shows similar structure and amplitude to that derived from Cariaco Basin foraminifera (Hughen et al., 2004, 2006), and the match is further improved if the latter is tied to the most recent Greenland ice core chronology (Svensson et al., 2008). These data are however in conflict with a previously published 14C data set for a stalagmite record from the Bahamas — GB-89-24-1 (Beck et al., 2001), which likely suffered from 14C analytical blank subtraction issues in the older part of the record. The new Bahamas speleothem ∆14C data do not show the extreme shifts between 44 and 40 ka reported in the previous study (Beck et al., 2001). Causes for the observed structure in derived atmospheric Δ14C variation based on the new speleothem data are investigated with a suite of simulations using an earth system model of intermediate complexity. Data-model comparison indicates that major fluctuations in atmospheric ∆14C during marine isotope stage 3 is primarily a function of changes in geomagnetic field intensity, although ocean–atmosphere system reorganisation also played a supporting role. Article in Journal/Newspaper Greenland Greenland ice core ice core CentAUR: Central Archive at the University of Reading Earth and Planetary Science Letters 289 1-2 1 10 |
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CentAUR: Central Archive at the University of Reading |
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ftunivreading |
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description |
We present a new speleothem record of atmospheric Δ14C between 28 and 44 ka that offers considerable promise for resolving some of the uncertainty associated with existing radiocarbon calibration curves for this time period. The record is based on a comprehensive suite of AMS 14C ages, using new low-blank protocols, and U–Th ages using high precision MC-ICPMS procedures. Atmospheric Δ14C was calculated by correcting 14C ages with a constant dead carbon fraction (DCF) of 22.7 ± 5.9%, based on a comparison of stalagmite 14C ages with the IntCal04 (Reimer et al., 2004) calibration curve between 15 and 11 ka. The new Δ14C speleothem record shows similar structure and amplitude to that derived from Cariaco Basin foraminifera (Hughen et al., 2004, 2006), and the match is further improved if the latter is tied to the most recent Greenland ice core chronology (Svensson et al., 2008). These data are however in conflict with a previously published 14C data set for a stalagmite record from the Bahamas — GB-89-24-1 (Beck et al., 2001), which likely suffered from 14C analytical blank subtraction issues in the older part of the record. The new Bahamas speleothem ∆14C data do not show the extreme shifts between 44 and 40 ka reported in the previous study (Beck et al., 2001). Causes for the observed structure in derived atmospheric Δ14C variation based on the new speleothem data are investigated with a suite of simulations using an earth system model of intermediate complexity. Data-model comparison indicates that major fluctuations in atmospheric ∆14C during marine isotope stage 3 is primarily a function of changes in geomagnetic field intensity, although ocean–atmosphere system reorganisation also played a supporting role. |
format |
Article in Journal/Newspaper |
author |
Hoffmann, Dirk L. Beck, J. Warren Richards, David A. Smart, Peter L. Singarayer, Joy S. Ketchmark, Tricia Hawkesworth, Chris J. |
spellingShingle |
Hoffmann, Dirk L. Beck, J. Warren Richards, David A. Smart, Peter L. Singarayer, Joy S. Ketchmark, Tricia Hawkesworth, Chris J. Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas |
author_facet |
Hoffmann, Dirk L. Beck, J. Warren Richards, David A. Smart, Peter L. Singarayer, Joy S. Ketchmark, Tricia Hawkesworth, Chris J. |
author_sort |
Hoffmann, Dirk L. |
title |
Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas |
title_short |
Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas |
title_full |
Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas |
title_fullStr |
Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas |
title_full_unstemmed |
Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas |
title_sort |
towards radiocarbon calibration beyond 28ka using speleothems from the bahamas |
publisher |
Elsevier |
publishDate |
2010 |
url |
https://centaur.reading.ac.uk/34558/ https://doi.org/10.1016/j.epsl.2009.10.004 |
genre |
Greenland Greenland ice core ice core |
genre_facet |
Greenland Greenland ice core ice core |
op_relation |
Hoffmann, D. L., Beck, J. W., Richards, D. A., Smart, P. L., Singarayer, J. S. <https://centaur.reading.ac.uk/view/creators/90005422.html>, Ketchmark, T. and Hawkesworth, C. J. (2010) Towards radiocarbon calibration beyond 28ka using speleothems from the Bahamas. Earth and Planetary Science Letters, 289 (1-2). pp. 1-10. ISSN 0012-821X doi: https://doi.org/10.1016/j.epsl.2009.10.004 <https://doi.org/10.1016/j.epsl.2009.10.004> |
op_doi |
https://doi.org/10.1016/j.epsl.2009.10.004 |
container_title |
Earth and Planetary Science Letters |
container_volume |
289 |
container_issue |
1-2 |
container_start_page |
1 |
op_container_end_page |
10 |
_version_ |
1810447659533598720 |