THE NORWEGIAN GREENLAND SEA CONTINENTAL MARGINS - MORPHOLOGY AND LATEQUATERNARY SEDIMENTARY PROCESSES AND ENVIRONMENT

The continental margins surrounding the Norwegian-Greenland Sea are to a large degree shaped by processes during the late Quaternary. The pa per gives an overview of the morphology and the processes responsible for the formation of three main groups of morphological features: slid es, trough mouth fans and channels. Several large late Quaternary slid es have been identified on the eastern Norwegian-Greenland Sea contine ntal margin. The origin of the slides may be due to high sedimentation rates leading to a build-up of excess pore water pressure, perhaps wi th additional pressure caused by gas bubbles. Triggering might have be en prompted by earthquakes or by decomposition of gas hydrates. Trough mouth fans (TMF) are fans at the mouths of transverse troughs on pres ently or formerly glaciated continental shelves. In the Norwegian-Gree nland Sea, seven TMFs have been identified varying in area from 2700 k m(2) to 215 000 km(2). The Trough Mouth Fans are depocentres of sedime nts which have accumulated in front of ice streams draining the large Northwest European ice sheets. The sediments deposited at the shelf br eak/upper slope by the ice stream were remobilized and transported dow nslope, mostly as debris flows. The Trough Mouth Fans hold the potenti al for giving information about the various ice streams feeding them w ith regard to velocity and ice discharge. Two large deep-sea channel s ystems have been observed along the Norwegian continental margin, the Lofoten Basin Channel and the Inbis Channel Along the East Greenland m argin, several channel systems have been identified. The deep-sea chan nels may have been formed by dense water originating from cooling, sea -ice formation and brine rejection close to the glacier margin or they may originate from small slides on the upper slope transforming into debris flows and turbidity currents. (C) 1998 Elsevier Science Ltd. Al l rights reserved.