Sedimentary environment and glacial history during the last 40 ka of the Vّring continental margin, mid-Norway

This study is based on detailed investigation of sediment cores and high resolution seismics. We identified and describe five lithofacies on the Vّring Plateau and eight on the mid-Norwegian continental slope. The various lithofacies are mainly related to the fluctuations of the Fennoscandian Ice Sheet and the varying intensity of bottom currents and inflow of Atlantic water masses. Ocean circulation was highly variable between 40 and 22 14C ka BP, being vigorous during interstadials and sluggish during stadials. Between ca 22 and 15 14C ka BP the sedimentary environment was significantly influenced by fluctuations of the Fennoscandian Ice Sheet, repeatedly reaching the outermost shelf. These fluctuations are reflected in the sedimentary record as ice-rafted debris (IRD) accumulation peaks, deposition of stratified diamicton, and glacigenic debris flows on the continental slope. During this period the sediment accumulation rate increased, bottom currents influenced the sedimentary pattern, and surface waters were seasonally ice-free, indicating inflow of Atlantic waters. Subsequent to ca 15 14C ka BP the glacier influence decreased as the margin of the Fennoscandian Ice Sheet retreated to reach the coast before 12.5 14C ka BP. The modern sedimentary environment is characterised by relatively strong bottom current action, causing winnowing or non-deposition down to approximately 1000 m water depth.