THE GLACIER-FED FAN AT THE MOUTH OF STORFJORDEN TROUGH, WESTERN BARENTS SEA - A COMPARATIVE-STUDY

The Middle and Late Pleistocene succession on the glacier-fed fan at t he mouth of Storfjorden trough was studied using high-resolution seism ic data. Seven glacial advances to the shelf break during Middle and L ate Pleistocene resulted in episodic high sediment input to the fan wi th real sedimentation rates of up to 172 cm/1000 years, separated by s ediment-starved interstadials and interglacials. On the upper fan the high sediment input resulted in frequent slides and slumps, generating debris flows which dominate the mid-fan strata. Compared with the lar ger neighbouring Bear Island trough mouth fan, the Storfjorden trough mouth fan has a steeper fan gradient, narrower, thinner and shorter de bris flow deposits and lower frequency of large scale sliding. Glacier -fed submarine fans receive their main sediment input from a glacier m argin at the shelf break, as opposed to river-fed fans where sediment input occurs through a channel-levee complex. As a result, the depocen tre of a river-fed fan is found on the mid-fan and the upper slope is mainly an area of sediment bypass, whereas the glacier-fed fan has an elongated depocentre across the uppermost fan. The river-fed fans are dominated by deposition from turbidity currents, whereas glacier-fed f ans are dominated by debris flow deposits.