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| Titel |
Duration of Greenland Stadial 22 and ice-gas Δage from counting of annual layers in Greenland NGRIP ice core |
| VerfasserIn |
P. Vallelonga, G. Bertagna, T. Blunier, H. A. Kjær, T. J. Popp, S. O. Rasmussen, J. P. Steffensen, C. Stowasser, A. S. Svensson, E. Warming, M. Winstrup, M. Bigler, S. Kipfstuhl |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 6 ; Nr. 8, no. 6 (2012-11-20), S.1839-1847 |
| Datensatznummer |
250005972
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| Publikation (Nr.) |
 copernicus.org/cp-8-1839-2012.pdf |
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| Zusammenfassung |
| High-resolution measurements of chemical impurities and methane
concentrations in Greenland ice core samples from the early glacial period
allow the extension of annual-layer counted chronologies and the improvement
of gas age-ice age difference (Δage) essential to the
synchronization of ice core records. We report high-resolution measurements
of a 50 m section of the NorthGRIP ice core and corresponding annual
layer thicknesses in order to constrain the duration of the Greenland
Stadial 22 (GS-22) between Greenland Interstadials (GIs) 21 and 22, for
which inconsistent durations and ages have been reported from Greenland and
Antarctic ice core records as well as European speleothems. Depending on the
chronology used, GS-22 occurred between approximately 89 (end of GI-22) and
83 kyr b2k (onset of GI-21). From annual layer counting, we find that GS-22
lasted between 2696 and 3092 years and was followed by a GI-21 pre-cursor
event lasting between 331 and 369 yr. Our layer-based counting agrees
with the duration of stadial 22 as determined from the NALPS speleothem
record (3250 ± 526 yr) but not with that of the GICC05modelext chronology (2620 yr) or
an alternative chronology based on gas-marker synchronization to EPICA
Dronning Maud Land ice core. These results show that GICC05modelext overestimates
accumulation and/or underestimates thinning in this early part of the last
glacial period. We also revise the possible ranges of NorthGRIP Δdepth (5.49 to 5.85 m) and Δage (498 to 601 yr) at the warming onset
of GI-21 as well as the Δage range at the onset of the GI-21
precursor warming (523 to 654 yr), observing that temperature (represented by
the δ15N proxy) increases before CH4 concentration by no
more than a few decades. |
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