The Stable nts in , 314 , fluctuations along the East Greenland continental margin

High-resolution stable oxygen and carbon isotope and sedimentological investigations were carried out on four westbeast profiles at the East Greenland continental margin between 68' and 7 5 O N. The sediment cores represent distinct glacial/ interglacial palaeoclimatic episodes over the past 190ka. Based on oxygen isotope stratigraphy and AMS '"C dating, our data can be well correlated with the global climate record. However, there are some excursions from the global climate Curve suggesting a local/ regional overprint by meltwater events of the Greenland Ice Sheet, especially at the beginning of isotope stage 3 and during Termination 1. Distinct high-amplitude variations in supply of ice-rafted debris (IRD) indicate repeated advances and retreats of the Greenland Ice Sheet, causing fluctuations in the massive production and transport of icebergs into the Greenland Sea. During the last 190ka, a number of IRD peaks appear to be correlated with cooling cycles observed in the GRIP Greenland Ice Core. Drastic events in iceberg discharge along the East Greenland continental margin recurred at very short intervals of 1000-3000 years (i.e. much more frequently than the about 10000years associated with Heinrich events), suggesting short-term collapses of the Greenland Ice Sheet on these time-scales. These late Weichselian Greenland Ice Sheet oscillations appear to be in phase with those in the Barents Sea area. Maximum flux rates of terrigenous (ice-rafted) material were recorded at the continental slope between about 21 and 16 ka, which may correspond to the maximum (stage 2) extension of glaciers on Greenland. The beginning of Termination I is documented by a distinct shift in the oxygen isotopes and a most prominent decrease in flux of IRD at the continental slope caused by the retreat of continental ice masses. Sedimentary processes, terrigenous sediment supply and biogenic productivity along the East Greenland continental margin are influenced by fluctuations in the extent of the Greenland Ice Sheet, the extent of sea ice, the rate of drifting icebergs, meltwater input and/ or oceanic circulation, i.e. factors which are all assumed to be controlled by climate (Figs 1 and 2). The reconstruction of this environmental history of the East Greenland margin and the correlation between terrestrial and marine records are major objectives of the ESFPONAM (European Science FoundationPolar North Atlantic Margins) programme (Elverhei & Dowdeswell 1991). Terrestrial field work on eastern Greenland (e.g. Hjort 1981; Funder 1989; Moller et al. 1991; Funder et al. 1994) and numerous investigations performed on marine sediments from the NorwegianGreenland Sea (e.g. Henrich et al. 1989; Gard & Backman 1990; Vogelsang 1990; KO$ Karpuz & Jansen 1992; Baumann et al. 1993) gave important information about changes in palaeoclimate during the last glacial/interglacial cycles. Only a few palaeoenvironmental studies, however, were performed in the heavily sea ice covered East Greenland continental margin area (e.g. Marienfeld 1992; Mienert et al. 1992; Stein et al. 1993; Williams 1993; Nam et al. 1995). Transport by icebergs is the main mechanism supplying terrigenous material here. In particular, the occurrence of sandand gravel-sized particles in marine sediments is assumed to be delivered by both icebergs and sea ice and is generally accepted to be a useful tool for identifying icerafted debris (IRD) input and reconstructing the activity of glaciers on land (e.g. Ruddiman 1977; Shackleton et al. 1984; Grobe 1987; Spielhagen 1991; Hebbeln et al. 1994; Fronval et al. 1995). As shown in the example of Fig. 3 the sedimentary records from the profile off Scoresby Sund (cf. Fig. 2) are characterized by highamplitude variations in IRD, suggesting major short-term variations in glacier extension on Greenland (Nam 1996). The IRD-rich horizons, interpreted as short-lived massive discharges of icebergs, are widespread features in the late Pleistocene North Atlantic and intensely investigated and discussed in the recent publications (e.g. Andrews & Tedesco 1992; Bond et al. 1992; Broecker er al. 1992: Bond & Lotti 1995). These so-called 'Heinrich layers' or 'Heinrich events' From Andrews, .l. T,, Austin. W. E. N., Bergsten, H. & Jennings, A. E. (eds). 1996, Late Quaternary Palaeoceanography of [he North Atlantic Margins, Geological Society Special Publication No. I l l , pp. 135-151