Numerical modelling of the Laurentide Ice Sheet in the Baffin Island region: the role of a Cumberland Sound ice stream

Abstract

A numerical model reconstruction was made of the northeastern Laurentide Ice Sheet in the Baffin Island - Foxe Basin region using geophysical, terrestrial, and marine geologic evidence for initial and boundary conditions. The simulated ice sheet consists of a Foxe Dome with additional smaller Hall and Amadjuak domes and a Penny Ice Divide. A specific objective was to determine boundary conditions that would allow advance of a marine-based low surface slope ice stream into and out of Cumberland Sound, a major marine embayment in the uplifted rim of the eastern Canadian Arctic (up to 1200 m deep), while maintaining ice free or nonsliding (e.g., cold-based) thin ice on adjacent plateaus of Cumberland Peninsula; this scenario accommodates interpretations based on terrestrial and marine studies in this region. After an initial ice-sheet configuration is placed on the eastern Arctic terrain, basal sliding is allowed in specified regions. Basal sliding below sea level and between the Foxe Dome and Cumberland Sound and a reasonable but critical initial ice sheet volume and dome surface elevation are needed to obtain advance along and out of Cumberland Sound. Rapid flow into Hudson Strait and along Cumberland Sound causes drawdown and a change in ice-sheet configuration. Although more Foxe Dome ice flows into western Hudson Strait than Cumberland Sound in the simulations, the latter may still have been an important conduit connecting the interior of the northeastern Laurentide Ice Sheet to the Labrador Sea, thereby affecting regional ice sheet dynamics, specifically ice surface elevations and flow paths.