Short Paper No significant ice-sheet expansion beyond present ice margins during the past 4500 yr at Rauer Group, East Antarctica Sonja Berg a, ⁎, Bernd Wagner a , Duanne A. White b , Martin Melles a a Institute of Geology and Mineralogy, University of Cologne, D-50674 Cologne, Germany b Department of Physical Geography, Macquarie University, NSW 2109, Australia abstract article info Article history: Received 17 November 2009 Available online 21 May 2010 Keywords: Rauer Group Glacial re-advance Holocene Marine sediments East Antarctica The history of glacial advances and retreats of the East Antarctic ice sheet during the Holocene is not well- known, due to limited field evidence in both the marine and terrestrial realm. A 257-cm-long sediment core was recovered from a marine inlet in the Rauer Group, East Antarctica, 1.8 km in front of the present ice- sheet margin. Radiocarbon dating and lithological characteristics reveal that the core comprises a complete marine record since 4500 yr. A significant ice-sheet expansion beyond present ice margins therefore did not occur during this period. © 2010 University of Washington. Published by Elsevier Inc. All rights reserved. Introduction The East Antarctic Ice Sheet (EAIS) currently holds ca. 79% of the global ice masses, which equals about 52 m of sea-level equivalent (Lythe et al., 2001). Mass-balance changes of the EAIS could thus have a significant impact on global sea level. However, mass-balance estimations for the EAIS indicate that only minor changes have occurred in recent decades (Mayewski et al., 2009), while the West Antarctic Ice Sheet (WIAS) is showing dynamic and large ice-volume fluctuations (Wingham et al., 2006), and the smaller ice areas on the Antarctic Peninsula (AP) are affected by the fast warming of the region (Vaughan et al., 2003). The reconstruction of past glacial advances and retreats is difficult because of the complex reactions of glacial systems on changes in accumulation rates and temperature (Goodwin, 1998). Advances of East Antarctic alpine glaciers, ice-sheet margins and outlet glaciers during the mid and late Holocene have been reconstructed from glaciological and geomorphological field evidence (e.g. see review by Hall, 2009). Yet, the extent of such advances is difficult to assess because robust chronological constraints are often lacking. Records that allow precise dating and recognition of small-scale changes are needed to improve the understanding of past changes of the EAIS under different climate conditions, and to help measure the regional variability of these changes and to gain a holistic view of the whole ice sheet. This is a major precondition to substantially improving future predictions about the impact of the recent global warming on ice sheets. The Prydz Bay region is a crucial site for reconstructing past developments of the EAIS, because it encompasses the largest drainage system in Antarctica (O'Brien et al., 2007). Field evidence for glacier and ice-sheet advances in the Prydz Bay region during the Holocene is sparse. A marine record from eastern Prydz Bay indicates a re-advance of floating glacial ice between ca. 7300 and 3800 14 C yr BP (Domack et al., 1991). This observation is, however, not confirmed by another record from the same area (Taylor and McMinn, 2002). In the Vestfold Hills, eastern Prydz Bay, Holocene ice retreat was interrupted by the so-called Chelnock Glaciation since 2000 14 C yr BP, when the northern margin of the Sørsdal outlet glacier expanded (Adamson and Pickard, 1983). A limited extent of Holocene glacial re- advances was proposed by Fitzsimons and Colhoun (1995), with ice advances of less than 500 m in the Vestfold Hills. A local glacier re- advance of unknown extent around ca. 2600 cal yr BP has been reconstructed from relative sea-level observations in nearby Larse- mann Hills (Verleyen et al., 2005). The Rauer Group, located between Larsemann Hills and Vestfold Hills, consists of several ice-free and low-lying islands (Fig. 1A) and is delimited by the EAIS to the east and bordered by outlet glaciers to the north and south. A rather stable ice-sheet margin, with maximum ice expansion of less than 500 m throughout the Holocene, is inferred from the degree of weathering of glacial deposits (White et al., 2009). However, precise dating of the deposition of the glacial erratics and moraines deposited on Rauer Group is difficult. A sediment core was recovered from a 6.3-m-deep marine inlet located at Shcherbinina Island in the northern Rauer Group (Fig. 1A). The distance from the coring location to the present ice-sheet margin Quaternary Research 74 (2010) 23–25 ⁎ Corresponding author. Fax: +49 221 470 5149. E-mail address: sberg0@uni-koeln.de (S. Berg). 0033-5894/$ – see front matter © 2010 University of Washington. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.yqres.2010.04.004 Contents lists available at ScienceDirect Quaternary Research journal homepage: www.elsevier.com/locate/yqres