LATE QUATERNARY CALCIUM-CARBONATE SEDIMENTATION AND TERRIGENOUS INPUTALONG THE EAST GREENLAND CONTINENTAL-MARGIN

Nine large box cores collected in the western Greenland-Iceland-Norweg ian (GIN) Sea were analyzed for calcium carbonate content and coarse f raction components. Stratigraphic control is based on oxygen isotope r ecords performed on four of the cores. All cores were correlated using oxygen and carbon isotope data, fluctuations in calcium carbonate con tent, coarse terrigenous particle content and volcanic ash beds. Glaci al and interglacial cycles are documented by a number of terrigenous p article events and differentiated calcium carbonate production which c an be correlated to major paleoceanographic and paleoclimatic shifts. In the older core sections, extensive deposition of ice-rafted detritu s (IRD) persisted until about oxygen isotope stage 9 and document a re latively stable environment in this area, strongly influenced by cold surface water masses. The following interval was characterized by vari ations in the general surface water circulation pattern, although high amounts of IRD are still present in Iceland Sea sediments. Pronounced shifts in terrigenous input and pelagic carbonate records were identi fied close to the oxygen isotope stage 9/8 and 6/5 boundaries, indicat ing massive melting of icebergs in the western GIN Sea. These enormous inputs of debris were followed by an increase in calcium carbonate pr oduction caused by maximum intrusion of warm Atlantic surface waters. Relatively high calcium carbonate contents also show that only little dilution by fine-grained material and a minimum of ice melting occurre d during these warm phases. During oxygen isotope stage 5, conditions were more uniform indicating a less pronounced westward penetration of Atlantic waters as compared to the Holocene. The last glacial (stages 4-2) is characterized by the occurrence of ''Heinrich''-like events, although high IRD contents were present throughout this interval. A di stinct contrast between the northernmost cores and the cores in the so uth is indicative of a rather strong westward penetration of Atlantic water in the north and of an area dominated by cold water east of the Kolbeinsey Ridge during the Holocene. However, conditions west of Jan Mayen seem to have remained constantly dominated by cold surface water s throughout the whole time investigated.