Holocene sedimentation in the Skagerrak interpreted from chirp sonar and core data

High-resolution chirp sonar profiling in the northeastern Skagerrak shows acoustically stratified sediments draping a rough-surfaced substratum. A 32 metre long sediment core retrieved from the survey area encompasses the entire Holocene and latest Pleistocene. The uppermost seismo-acoustic units in the chirp profiles represent Holocene marine sediments. The lowermost unit is interpreted as ice-proximal glacial-marine sediments rapidly deposited during the last deglaciation. The end of ice-proximal sedimentation is marked by a strong reflector, interpreted to have been formed during latest Pleistocene time as a consequence of rapid ice retreat and drastically lowered sedimentation rate. The subsequent distal glacial-marine sediments were deposited with initially high sedimentation rates caused by an isostatic rebound-associated sea-level fall. Based on correlation between the core and the chirp sonar profiles using measured sediment physical properties and AMS C-14 dating, we propose a revised position for the Pleistocene/Holocene boundary in the seismo-acoustic stratigraphy of the investigated area. Copyright (C) 2005 John Wiley Sons, Ltd.