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| Titel |
The Antarctic ice core chronology (AICC2012): an optimized multi-parameter and multi-site dating approach for the last 120 thousand years |
| VerfasserIn |
D. Veres, L. Bazin, A. Landais, H. Toye Mahamadou Kele, B. Lemieux-Dudon, F. Parrenin, P. Martinerie, E. Blayo, T. Blunier, E. Capron, J. Chappellaz, S. O. Rasmussen, M. Severi, A. Svensson, B. Vinther, E. W. Wolff |
| 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 ; 9, no. 4 ; Nr. 9, no. 4 (2013-08-01), S.1733-1748 |
| Datensatznummer |
250018103
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| Publikation (Nr.) |
 copernicus.org/cp-9-1733-2013.pdf |
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| Zusammenfassung |
The deep polar ice cores provide reference records commonly employed in
global correlation of past climate events. However, temporal divergences
reaching up to several thousand years (ka) exist between ice cores over the
last climatic cycle. In this context, we are hereby introducing the
Antarctic Ice Core Chronology 2012 (AICC2012), a new and coherent timescale
developed for four Antarctic ice cores, namely Vostok, EPICA Dome C (EDC),
EPICA Dronning Maud Land (EDML) and Talos Dome (TALDICE), alongside the
Greenlandic NGRIP record. The AICC2012 timescale has been constructed using
the Bayesian tool Datice (Lemieux-Dudon et al., 2010) that combines
glaciological inputs and data constraints, including a wide range of
relative and absolute gas and ice stratigraphic markers. We focus here on
the last 120 ka, whereas the companion paper by Bazin et al. (2013) focuses
on the interval 120–800 ka.
Compared to previous timescales, AICC2012 presents an improved timing for the
last glacial inception, respecting the glaciological constraints of all
analyzed records. Moreover, with the addition of numerous new stratigraphic
markers and improved calculation of the lock-in depth (LID) based on
δ15N data employed as the Datice background scenario, the AICC2012
presents a slightly improved timing for the bipolar sequence of events over
Marine Isotope Stage 3 associated with the seesaw mechanism, with maximum
differences of about 600 yr with respect to the previous Datice-derived
chronology of Lemieux-Dudon et al. (2010), hereafter denoted LD2010. Our
improved scenario confirms the regional differences for the millennial scale
variability over the last glacial period: while the EDC isotopic record
(events of triangular shape) displays peaks roughly at the same time as the
NGRIP abrupt isotopic increases, the EDML isotopic record (events
characterized by broader peaks or even extended periods of high isotope
values) reached the isotopic maximum several centuries before.
It is expected that the future contribution of both other long ice core
records and other types of chronological constraints to the Datice tool will
lead to further refinements in the ice core chronologies beyond the AICC2012
chronology. For the time being however, we recommend that AICC2012 be used as
the preferred chronology for the Vostok, EDC, EDML and TALDICE ice core
records, both over the last glacial cycle (this study), and beyond (following
Bazin et al., 2013). The ages for NGRIP in AICC2012 are virtually identical
to those of GICC05 for the last 60.2 ka, whereas the ages beyond are
independent of those in GICC05modelext (as in the construction of AICC2012,
the GICC05modelext was included only via the background scenarios and not as
age markers). As such, where issues of phasing between Antarctic records
included in AICC2012 and NGRIP are involved, the NGRIP ages in AICC2012
should therefore be taken to avoid introducing false offsets. However for
issues involving only Greenland ice cores, there is not yet a strong basis to
recommend superseding GICC05modelext as the recommended age scale for
Greenland ice cores. |
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