Abstract

Abstract. Whereas ice cores from high-accumulation sites in coastal Antarctica clearly demonstrate annual layering, it is debated whether a seasonal signal is also preserved in ice cores from lower-accumulation sites further inland and particularly on the East Antarctic Plateau. In this study, we examine 5 m of early Holocene ice from the Dome Fuji (DF) ice core at a high temporal resolution by continuous flow analysis. The ice was continuously analysed for concentrations of dust, sodium, ammonium, liquid conductivity, and water isotopic composition. Furthermore, a dielectric profiling was performed on the solid ice. In most of the analysed ice, the multi-parameter impurity data set appears to resolve the seasonal variability although the identification of annual layers is not always unambiguous. The study thus provides information on the snow accumulation process in central East Antarctica. A layer counting based on the same principles as those previously applied to the NGRIP (North Greenland Ice core Project) and the Antarctic EPICA (European Project for Ice Coring in Antarctica) Dronning Maud Land (EDML) ice cores leads to a mean annual layer thickness for the DF ice of 3.0 ± 0.3 cm that compares well to existing estimates. The measured DF section is linked to the EDML ice core through a characteristic pattern of three significant acidity peaks that are present in both cores. The corresponding section of the EDML ice core has recently been dated by annual layer counting and the number of years identified independently in the two cores agree within error estimates. We therefore conclude that, to first order, the annual signal is preserved in this section of the DF core. This case study demonstrates the feasibility of determining annually deposited strata on the central East Antarctic Plateau. It also opens the possibility of resolving annual layers in the Eemian section of Antarctic ice cores where the accumulation is estimated to have been greater than in the Holocene.

Highlights

  • The detection of annual layers has long been the method of preference for obtaining high-precision ice core chronologies (Alley et al, 1997; Hammer et al, 1978)

  • Ice core dating based on annual layer counting is limited by the temporal resolution of the ice, but it is feasible for annual layers thicknesses down to about 1 cm by the application of continuous flow analysis (Vallelonga et al, 2012)

  • The high-resolution impurity profiles obtained from the early Holocene section of the Dome Fuji ice core demonstrate the feasibility of determining annually deposited strata on the central East Antarctic Plateau during warm climates

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Summary

Introduction

The detection of annual layers has long been the method of preference for obtaining high-precision ice core chronologies (Alley et al, 1997; Hammer et al, 1978). The volcanic synchronization between the Dome Fuji and the EDC ice cores revealed periods where no reliable tie points could be identified in MISs 2, 4, 5b, and 6 (Fujita et al, 2015). We present high-resolution chemistry and dust data from a 5.0 m section of early Holocene ice from the Dome Fuji 1 ice core. Based on this data set we attempt to date the DF ice by annual layer counting and we discuss issues related to layer counting at low-accumulation sites. The synchronization of the three cores allows for a comparison of their respective timescales over the time interval of synchronization, allowing for an evaluation of the DF layer counting

Analyses and results
Layer counting
Synchronizing DF to EDML and NGRIP
Dust peaks
Findings
A peculiar event
Conclusions
Full Text
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