GLACIATION, CLIMATE HISTORY, CHANGING MARINE LEVELS AND THE EVOLUTIONOF THE NORTHEAST WATER POLYNYA

The morphology of the bank- and trough system in the Northeast Water ( NEW) polynya area is to a large extent a result of glacial erosion and deposition by an extended Inland Ice which reached the continental sh elf. The last deglaciation of the fjords and forelands adjacent to the polynya took place shortly before 9000 radiocarbon yr B.P. At that ti me the marine level stood 80 m higher than today, which meant a water depth over much of the Ob Bank and parts of the Belgica Bank twice as deep as presently. This probably gave the East Greenland Current a mor e unimpeded southward flow, with less eddy effects. In combination wit h the generally warmer climate of the early Holocene (with less ice co ming out of the Polar Basin, a larger influx of Atlantic Water leading to more ice melting in the NEW area, and probably no ice drift hinder ing fast-ice barrier in the south), this probably meant that no polyny a existed at that time. Instead there was a more general open water su mmer situation. After 5000 yr B.P. climate deteriorated and glaciers e xpanded. As the isostatic rise of land and near coast bottoms continue d, resulting in shallowing banks, both the bathymetric and climatic si tuation responsible for the existence of today's polynya gradually cam e into existence. The shallowing Ob Bank began to obstruct ice drift f rom the north and an ice-drift hindering fast-ice barrier was created in the south. But even after 5000 yr B.P. it is likely that shorter sp ells of more generally open water existed, during which marine based p aleoeskimos (Independence II) and neoeskimos (Thule) immigrated along the at other times totally ice-bound coasts of North Greenland.