Revisiting the absolute calibration of the Greenland ice-core age-scales*
Recently, an absolute "calibration" was proposed for the GRIP and GISP2 Greenland ice-core time scales (Shackleton et al., 2004). This calibration attempted to reconcile the stratigraphic integration of ice-core, marine and speleothem archives with the absolute age constraints that marine...
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ftdoajarticles:oai:doaj.org/article:d43ce829e7364dcd85faf952d483fb3a 2023-05-15T16:27:34+02:00 Revisiting the absolute calibration of the Greenland ice-core age-scales* L. C. Skinner 2008-11-01T00:00:00Z https://doaj.org/article/d43ce829e7364dcd85faf952d483fb3a EN eng Copernicus Publications http://www.clim-past.net/4/295/2008/cp-4-295-2008.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 https://doaj.org/article/d43ce829e7364dcd85faf952d483fb3a Climate of the Past, Vol 4, Iss 4, Pp 295-302 (2008) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2008 ftdoajarticles 2022-12-31T06:55:59Z Recently, an absolute "calibration" was proposed for the GRIP and GISP2 Greenland ice-core time scales (Shackleton et al., 2004). This calibration attempted to reconcile the stratigraphic integration of ice-core, marine and speleothem archives with the absolute age constraints that marine and speleothem records incorporate. Here we revisit this calibration in light of the new layer-counted chronology of the NGRIP ice-core (GICC05). The GICC05 age-scale differs from the proposed absolute calibration by up to 1200 years late in the last glaciation, with implications both for radiocarbon cycling and the inferred timing of North Atlantic climate events relative to radiometrically dated archives (e.g. relative sea-level). By aligning the stratigraphy of Iberian Margin marine cores with that of the Greenland ice-cores, it can be shown that either: 1) the radiocarbon content of mid-latitude Atlantic surface-waters was extremely depleted (resulting in average surface reservoir ages up to 1700 years prior to ~22 ka BP); or 2) the GICC05 age-scale includes too few years (is up to 1200 years too young). It is shown here that both of these possibilities are probably correct to some degree. Based on the assumed accuracy of coral and speleothem U-Th ages, Northeast Atlantic surface reservoir ages should be revised upward by ~350 years, while the NGRIP age-scale appears to be "missing" time. These findings illustrate the utility of integrated stratigraphy as a test for our chronologies, which are rarely truly "absolute". This is an important point, since probably the worst error that we can make is to entrench and generalise a precise stratigraphical relationship on the basis of erroneous absolute age assignations. Article in Journal/Newspaper Greenland Greenland ice core Greenland ice cores GRIP ice core NGRIP North Atlantic Northeast Atlantic Directory of Open Access Journals: DOAJ Articles Shackleton Greenland |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 L. C. Skinner Revisiting the absolute calibration of the Greenland ice-core age-scales* |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
Recently, an absolute "calibration" was proposed for the GRIP and GISP2 Greenland ice-core time scales (Shackleton et al., 2004). This calibration attempted to reconcile the stratigraphic integration of ice-core, marine and speleothem archives with the absolute age constraints that marine and speleothem records incorporate. Here we revisit this calibration in light of the new layer-counted chronology of the NGRIP ice-core (GICC05). The GICC05 age-scale differs from the proposed absolute calibration by up to 1200 years late in the last glaciation, with implications both for radiocarbon cycling and the inferred timing of North Atlantic climate events relative to radiometrically dated archives (e.g. relative sea-level). By aligning the stratigraphy of Iberian Margin marine cores with that of the Greenland ice-cores, it can be shown that either: 1) the radiocarbon content of mid-latitude Atlantic surface-waters was extremely depleted (resulting in average surface reservoir ages up to 1700 years prior to ~22 ka BP); or 2) the GICC05 age-scale includes too few years (is up to 1200 years too young). It is shown here that both of these possibilities are probably correct to some degree. Based on the assumed accuracy of coral and speleothem U-Th ages, Northeast Atlantic surface reservoir ages should be revised upward by ~350 years, while the NGRIP age-scale appears to be "missing" time. These findings illustrate the utility of integrated stratigraphy as a test for our chronologies, which are rarely truly "absolute". This is an important point, since probably the worst error that we can make is to entrench and generalise a precise stratigraphical relationship on the basis of erroneous absolute age assignations. |
format |
Article in Journal/Newspaper |
author |
L. C. Skinner |
author_facet |
L. C. Skinner |
author_sort |
L. C. Skinner |
title |
Revisiting the absolute calibration of the Greenland ice-core age-scales* |
title_short |
Revisiting the absolute calibration of the Greenland ice-core age-scales* |
title_full |
Revisiting the absolute calibration of the Greenland ice-core age-scales* |
title_fullStr |
Revisiting the absolute calibration of the Greenland ice-core age-scales* |
title_full_unstemmed |
Revisiting the absolute calibration of the Greenland ice-core age-scales* |
title_sort |
revisiting the absolute calibration of the greenland ice-core age-scales* |
publisher |
Copernicus Publications |
publishDate |
2008 |
url |
https://doaj.org/article/d43ce829e7364dcd85faf952d483fb3a |
geographic |
Shackleton Greenland |
geographic_facet |
Shackleton Greenland |
genre |
Greenland Greenland ice core Greenland ice cores GRIP ice core NGRIP North Atlantic Northeast Atlantic |
genre_facet |
Greenland Greenland ice core Greenland ice cores GRIP ice core NGRIP North Atlantic Northeast Atlantic |
op_source |
Climate of the Past, Vol 4, Iss 4, Pp 295-302 (2008) |
op_relation |
http://www.clim-past.net/4/295/2008/cp-4-295-2008.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 https://doaj.org/article/d43ce829e7364dcd85faf952d483fb3a |
_version_ |
1766016959557664768 |