Landscape evolution and slide processes in a glacioisostatic rebound area; a combined marine and terrestrial approach

Abstract

Thick fine-grained, nonuniformly stratified deposits along a 20 km stretch coastline have been investigated using a combined marine and terrestrial approach. The sediments were deposited rapidly in glaciomarine, marine and submarine ice-contact environments during the Allerød and Younger Dryas periods. Rapid glacioisostatic rebound caused extensive modification of the landscape, mainly by sliding. Slides in the area were affected by the bedrock morphology, location and sedimentation rate of the glaciomarine sediments, isostatic rebound, presence of gas/fluids in marine sediments and later, river incision, tides and groundwater flow. Spatial and temporal distribution of slide deposits in the marine stratigraphy, and morphology of submarine and terrestrial features give detailed information of landscape evolution through time. This is illustrated by conceptual profiles from three areas that explain the landscape evolution and changing processes during the rebound. The most intensive slide activity, both in frequencies and volumes, and hence the most considerable landscape modification occurred early in the Holocene period i.e. when the relative sea level fell most rapidly.