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The record of glacier fluctuations in western Scandinavia, as reconstructed from continental data, has been correlated with records of ice-rafted detritus (IRD) from well-dated sediment cores from the Norwegian Sea covering the past 150,000 yr B.P. The input of IRD into the ocean is used as a proxy for ice sheet advances onto the shelf and, thus, for the calibration of a glaciation curve. The marine results generally support land-based reconstructions of glacier fluctuations and improve the time-control on glacial advances. The Saalian ice sheet decayed very rapidly approximately 125,000 yr B.P. In the Early Weichselian, a minor but significant IRD maximum indicates the presence of icebergs in isotope substage 5b (especially between 95,000 and 83,000 yr B.P.). Reduced amounts of calcareous nannofossils indicate that surface waters were influenced by meltwater discharges during isotope substages 5d and 5b. An extensive build-up of inland ice began again during isotope stage 4, but maximum glaciation was reached only in early stage 3 (58,000-53,000 yr B.P.). Marine sediments have minimum carbonate content, indicating strong dilution by lithogenic ice-rafted material. Generally, the IRD accumulation rate was considerably higher in stages 4-2 than in stage 5. A marked peak in IRD accumulation rates from 47,000 to 43,000 yr B.P. correlates well with a second Middle Weichselian ice sheet advance dated by the Laschamp/Olby paleomagnetic event. Minimum ice extent during the Ålesund interstade (38,500-32,500 yr B.P.) and several glacial oscillations during the Late Weichselian are also seen in the IRD record. Of several late Weichselian glacial oscillations on the shelf, at least four correspond to the North Atlantic Heinrich events. Ice sheet behavior was either coupled or linked by external forcing during these events, whereas internal ice sheet mechanisms may account for the noncoherent fluctuations.

High-resolution clay mineralogical investigations and their comparison with other sedimentological data from ODP Sites 908 and 909 (central Fram Strait) were used to reconstruct the paleoclimate and paleoceanography in the high northern latitudes since the Middle Miocene. Ice rafting has probably occurred since 15 Ma. The comparison of sand-sized components and clay mineral distribution demonstrate that both were not delivered by the same transport process. The input of the clay fraction is related to transport through sea ice and/or oceanic currents. A provenance change at 11.2 Ma is indicated by variations within clay mineral distribution and increased accumulation rates. This is interpreted as a result of an increase in water mass exchange through the Fram Strait. Decreases of the smectite to illite and chlorite ratio at Site 909 suggest a Middle

Coarse-fraction sediment (>63 µm) studies for Leg 151 Sites 908 and 909 have enabled us to reconstruct the paleoclimate since the early Miocene (18.0 Ma) of the Fram Strait, in order to better understand this gateway between the North Atlantic and the Arctic Ocean. Study of the grain-size distribution patterns (subfractions 63-125 µm, 125-250 µm, 250-500 µm, 500-1000 µm, and >IOOO µm plus the coarse-component composition) suggests possible seasonal ice-rafting starting as early as 14.0 Ma. Also shown is a clear signal of ice-rafting events between 10.8 and 8.6 Ma, 7.2 and 6.8 Ma, 6.3 and 5.5 Ma, and since 5.0 Ma. Evidence indicates that the initiation of the East Greenland Current took place at 10.8 Ma and is related to the reorganization and shutdown of deep-water connections in the Middle and Central American Seaways during the latest middle to late Miocene. During the Pliocene-Pleistocene, the polar front moved over Site 908, covering the area with sea ice and pack ice during the Pleistocene (between 1.9 and 1.2 Ma). The West Spitsbergen Current episodically reached the Fram Strait during the Pliocene-Pleistocene, suggesting that the Norwegian Sea was never completely covered by sea ice and pack ice in that era.

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