A new 27 ky high resolution East Antarctic climate record

Abstract

Abstract. The ice core recently drilled at the Dome Concordia site on the East Antarctic plateau provides a new high resolution isotope record covering part of the last glacial, the last transition and the Holocene. The two step shape of the deglaciation is remarkably similar for all the ice cores now available on the East Antarctic plateau. The first warming trend ends about 14000 years ago and is followed by the well marked Antarctic Cold Reversal (ACR) with a secondary peak common to all records. During the deglaciation, there are more similarities between the near coastal site of Taylor Dome and inland East Antarctica than between Taylor Dome and central Greenland. However, the results for EPICA do appear to confirm the Taylor Dome timescale after about 14 ka, showing cooling into the ACR roughly in phase between Greenland and Antarctica. While the overall deglacial pattem is asynchronous, this suggests that the now classical picture of a temperature seesaw between Antarctica and Greenland may be too simplistic.

A late-glacial high-resolution site and source temperature record derived from the EPICA Dome C isotope records (East Antarctica)

“…The remarkable similarity between these isotopic £uctuations suggests a common atmospheric climate history during the late glacial and the deglaciation over this part of the East Antarctic Plateau. As already noted in [37], there is an o¡set of about 5x between EDC96 and old Dome C ND. This isotopic di¡erence is attributed to more intense isotopic distillation at EPICA, with more depleted isotopic values and smaller accumulation rates at the EPICA site (typically 15% less) than at the old Dome C [37].…”

“…Both the original old Dome C and the GT4 Vostok time scales are signi¢cantly younger than EDC1, which is the direct result of the age assigned to the 10 Be peak that was used to derive the old Dome C and Vostok chronologies. After accounting for these chronological discrepancies, the excellent agreement observed during the deglaciation [37] between the EDC96, Vostok and old Dome C ND pro¢les is still valid for the glacial ( Fig. 2A): most of the oscillations occurring during the glacial are recognised in all ND records but they are more clearly de¢ned in the EDC96 pro¢le due to its higher resolution, the excellent quality of the core and improved analytical precision.…”

“…Drilling operations had to be resumed from the surface and this second drilling [36] reached the depth of 3200 m at the end of the 2002^2003 ¢eld season. Deuterium [37] and deuterium excess [31] pro¢les have already been published for the upper part of the ¢rst core, hereafter EDC96, and sampled down to 585 m during the 1997^1998 drilling season. New deuterium and oxygen 18 data presented in this article cover the additional 200 m of EDC96, recovered one year later.…”

“…The isotopic measurements were carried out with a depth resolution of 55 cm (bag samples) with 370 new measurements down to the bottom of the core. Analytical methods are as described in [37] and [31] with an accuracy (1c) of þ 0.5x and þ 0.05x for ND and N 18 O respectively (both being expressed in per mil with respect to V-SMOW, the Vienna Standard Mean Ocean Water). The resulting accuracy for the deuterium excess is of þ 0.7x.…”

Synoptic climate change as a driver of late Quaternary glaciations in the mid-latitudes of the Southern Hemisphere

“…Recent spectral analyses on varved lake sediments have highlighted the possibility of a periodically enhanced inter-annual El Niño Southern Oscillation (ENSO) signal during the LGIT over New Zealand (Pepper et al, 2004). Speleothem data from the South Island (Hellstrom et al, 1998) now supported by uranium isotope data (Robinson et al, 2004) also indicate a period of enhanced precipitation over New Zealand at around 13 ka which may be linked to a late glacial Southern Hemisphere climate event known as the Antarctic Cold Reversal (ACR) (Jouzel et al, 2001). An ACR signal has recently been recognized in New Zealand pollen and maar lake records (Pepper et al, 2004).…”