A refined TALDICE-1a age scale from 55 to 112 ka before present for the Talos Dome ice core based on high-resolution methane measurements

S Schüpbach,T F Stocker,M Bigler,U Federer,H Fischer

doi:10.5194/cp-7-1001-2011

Abstract

Abstract. A precise synchronization of different climate records is indispensable for a correct dynamical interpretation of paleoclimatic data. A chronology for the TALDICE ice core from the Ross Sea sector of East Antarctica has recently been presented based on methane synchronization with Greenland and the EDC ice cores and δ18Oice synchronization with EDC in the bottom part (TALDICE-1). Using new high-resolution methane data obtained with a continuous flow analysis technique, we present a refined age scale for the age interval from 55–112 thousand years (ka) before present, where TALDICE is synchronized with EDC. New and more precise tie points reduce the uncertainties of the age scale from up to 1900 yr in TALDICE-1 to below 1100 yr over most of the refined interval and shift the Talos Dome dating to significantly younger ages during the onset of Marine Isotope Stage 3. Thus, discussions of climate dynamics at sub-millennial time scales are now possible back to 110 ka, in particular during the inception of the last ice age. Calcium data of EDC and TALDICE are compared to show the impact of the refinement to the synchronization of the two ice cores not only for the gas but also for the ice age scale.

Highlights

For a good understanding of the mechanisms at work in the climate system it is indispensable to know the chronology and phase relationships of climate events in the past
Using new high-resolution methane data obtained with a continuous flow analysis technique, we present a refined age scale for the age interval from 55–112 thousand years before present, where Talos Dome Ice core Project (TALDICE) is synchronized with EPICA Dome C (EDC)
Correlation coefficients between EDC CH4 and Continuous Flow Analysis (CFA)-CH4 on the TALDICE-1 age scale and on the revised TALDICE1a age scale have been calculated by linearly interpolating the CFA-CH4 record to obtain concentration values in the high-resolution record at exactly the same age as the EDC data points

Summary

Introduction

For a good understanding of the mechanisms at work in the climate system it is indispensable to know the chronology and phase relationships of climate events in the past. Methane is well suited for such a synchronization because abrupt concentration changes have been observed over large periods back to 800 thousand years before present (ka BP, i.e. before 1950 AD), at glacial-interglacial transitions and during glacial times, especially during Dansgaard-Oeschger (DO) events (Brook et al, 2000; Chappellaz et al, 1997; Huber et al, 2006; Loulergue et al, 2008; Spahni et al, 2005)

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