The surficial geology record of ice stream catchment dynamics and ice-divide migration in the Quebec-Labrador sector of the Laurentide Ice Sheet

Abstract

The surficial geology of an approximately 30 000 km2 region in northeastern Quebec and western Labrador was mapped to elucidate the glacial dynamics of a region that experienced ice divide migrations and determine the net effect of this evolution on the glacial landscape. This region is located in one of the major inner-ice dispersal centres of the Laurentide Ice Sheet, the Quebec-Labrador Sector, and therefore provides important information on the overall dynamics of the interior of an ice sheet throughout a glaciation. Along with detailed surficial mapping, landform analysis was conducted to assess changes in ice stream catchments and related ice divide migration and understand their impact on the overall landform record. This work is a synthesis of a four-year mapping program that resulted in the completion of eight 1:100 000 scale surficial geology maps that included three years of field-based investigations. Mapping has revealed a complex landscape with a diverse suite of surficial deposits and a fragmented and overprinted mosaic of landforms, which provides evidence for polythermal subglacial conditions that evolved throughout glaciation.

Keywords

• Surficial mapping
• Laurentide ice sheet
• Ice sheet dynamics
• Glacial landforms