Volcanic synchronization of Dome Fuji and Dome C Antarctic deep ice cores over the past 216 kyr

H. Motoyama,E. W. Wolff,S. Fujita,M. Severi,F. Parrenin

doi:10.5194/cp-11-1395-2015

Abstract

Abstract. Two deep ice cores, Dome Fuji (DF) and EPICA Dome C (EDC), drilled at remote dome summits in Antarctica, were volcanically synchronized to improve our understanding of their chronologies. Within the past 216 kyr, 1401 volcanic tie points have been identified. DFO2006 is the chronology for the DF core that strictly follows O2 / N2 age constraints with interpolation using an ice flow model. AICC2012 is the chronology for five cores, including the EDC core, and is characterized by glaciological approaches combining ice flow modelling with various age markers. A precise comparison between the two chronologies was performed. The age differences between them are within 2 kyr, except at Marine Isotope Stage (MIS) 5. DFO2006 gives ages older than AICC2012, with peak values of 4.5 and 3.1 kyr at MIS 5d and MIS 5b, respectively. Accordingly, the ratios of duration (AICC2012 / DFO2006) range between 1.4 at MIS 5e and 0.7 at MIS 5a. When making a comparison with accurately dated speleothem records, the age of DFO2006 agrees well at MIS 5d, while the age of AICC2012 agrees well at MIS 5b, supporting their accuracy at these stages. In addition, we found that glaciological approaches tend to give chronologies with younger ages and with longer durations than age markers suggest at MIS 5d–6. Therefore, we hypothesize that the causes of the DFO2006–AICC2012 age differences at MIS 5 are (i) overestimation in surface mass balance at around MIS 5d–6 in the glaciological approach and (ii) an error in one of the O2 / N2 age constraints by ~ 3 kyr at MIS 5b. Overall, we improved our knowledge of the timing and duration of climatic stages at MIS 5. This new understanding will be incorporated into the production of the next common age scale. Additionally, we found that the deuterium signals of ice, δDice, at DF tends to lead the one at EDC, with the DF lead being more pronounced during cold periods. The lead of DF is by +710 years (maximum) at MIS 5d, −230 years (minimum) at MIS 7a and +60 to +126 years on average.

Highlights

Ice core records are rich archives of climate history over timescales of glacial-interglacial cycles up to ∼ 800 kyr before present (BP; e.g. European Project for Ice Coring in Antarctica (EPICA) Community Members, 2004; Kawamura et al, 2007; Petit et al, 1999)
The EPICA Dome C (EDC)-Dome Fuji (DF) volcanic matching consists of 1401 depth tie points (Fig. 2 and all records of synchronization in the Supplement A)
The models include DFO2006, AICC2012, EDC3, DFGT2006 and ages of the speleothem records from China

Summary

Introduction

Ice core records are rich archives of climate history over timescales of glacial-interglacial cycles up to ∼ 800 kyr before present (BP; e.g. EPICA Community Members, 2004; Kawamura et al, 2007; Petit et al, 1999). In ice core studies, dating is a central issue that must be investigated in order to better constrain the timing, sequence and duration of past climatic events and stages (e.g. Bazin et al, 2013; Kawamura et al, 2007; Parrenin et al, 2004, 2007a; Veres et al, 2013; Lemieux-Dudon et al, 2010). S. Fujita et al.: Antarctic deep ice cores over the past 216 kyr los Dome (TALDICE)) have been made (Bazin et al, 2013; Lemieux-Dudon et al, 2010; Veres et al, 2013). To better constrain common age scales, synchronization of deep ice cores using common events such as volcanic markers is a very important task

Methods

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Discussion

Conclusion