HISTORY OF A STABLE ICE MARGIN EAST GREENLAND DURING THE MIDDLE AND UPPER PLEISTOCENE

The East Greenland record of glaciation and environmental change is ba sed on a combination of onshore and offshore studies. Glaciological wo rk on contemporary outlet glaciers provides background for interpretin g the glaciation styles of the past. The Scoresby Sund fjord system, t he single largest outlet of the Inland Ice in East Greenland, and the adjacent continental shelf and slope, were the main working areas. The regionality of these results was tested with onshore and offshore wor k on sites further to the north in the East Greenland fjord zone. The record spans the period since Isotope Stage 7 (ca 240 ka). The most ex tensive glaciation phases were the Lollandselv and Scoresby Sund glaci ations (Isotope Stages 7 and 6). The Langelandselv interglaciation (Is otope Substage 5e) comprises shallow marine sediments at more than 20 sites onshore, and Cibicides wuellerstorfii carrying sediments on the continental slope. Summer temperatures were 2-3 degrees warmer than th e Holocene optimum, and there was vigorous advection of warm Atlantic water into the fjords. The warm period seems to be accompanied by a eu static sea-level rise of ca 20 m. During the Weichselian there were th ree major glacier advances, the Aucellaelv, Jyllandselv, and Fiakkerhu k stades (Isotope Substages 5d, ?5b, and Stages 3-2). All three advanc es mark a shift from one topographically determined stable position to another. In each phase the glaciers occupied almost the same space in the fjord basins and had their fronts on the inner shelf. But the gla cial regime and duration was different. The Aucellaelv stade lasted ca 10 ka, and the regime resembled that of present day outlet glaciers 6 00 km further to the north. The Flakkerhuk stade lasted for ca 50 ka, but left only thin and sporadic till, as well as glaciolacustrine sedi ments in ice-dammed river valleys. The regime was polar, similar to pr esent day glaciers in Antarctica. Its culmination, the last glacial ma ximum, in the period between 22 and 14 ka, is shown by a maximum in IR D deposition on the continental slope. After 12 ka, and before 10 ka, the outer fjord basins in the southern fjord zone had been abandoned b y the glaciers, and at ca 9.5 ka the last resurgence, the Milne Land s tade, had ended. (C) 1998 Published by Elsevier Science Ltd. All right s reserved.