Pre-Laurentide and Deglacial History of the Edmonton Region, Alberta, Canada

  • Author / Creator
    Rubin, Allison
  • The Edmonton-area landscape has been shaped by multiple geomorphic events throughout the Quaternary period. These events account for the distribution of resources and landforms across Central Alberta, making their reconstruction essential to understanding the geomorphic history of the Canadian Prairies. Such reconstructions are limited despite their inferred broader significance, and in the Edmonton region, multiple key Quaternary events have not been revisited in the 21st century. This thesis addresses this knowledge gap by reconstructing the pre-Laurentide buried valley drainage system within Central Alberta and the deglacial formation and drainage of glacial Lake Edmonton – two events that occurred within the Quaternary period and have influenced the geomorphology of the Edmonton region. The general location of the Edmonton-area buried valleys, known collectively as the Beverly valley network, and their hydrogeologic potential has been investigated in previous studies, but a detailed analysis of the valley geometry and lithostratigraphy has not yet been completed. The study presented in this thesis maps the extent and thalweg position of the Beverly catchment using water well drilling records and surface exposures in addition to creating a geologic framework for the valley lithostratigraphy. The results suggest sediment supply at the valley source to be a major control on downstream coarse sediment distribution. Previously reported radiocarbon dates suggest that the buried valleys within the Beverly network likely formed ~20 – 50,000 years BP. These findings prompt future investigations on the Beverly network flow systems and aquifer potential as additional water sources for the Edmonton region are explored. The second study presented here focuses on reconstructing glacial Lake Edmonton – a proglacial lake that formed over the Edmonton area during the retreat of the Laurentide Ice Sheet. Previous studies have acknowledged its formation and subsequent drainage through the Gwynne outlet, but the palaeohydraulics of its drainage have yet to be quantified. Five stages of lake formation are delineated and a HEC-GeoRAS/HEC-RAS system is used with palaeo-depth indicators to model the palaeo-bed topography of the Gywnne outlet. The peak discharge derived from lake volume and spillway incision is estimated as 25,000 – 95,000 m3sec-1, resulting in a minimum flow duration of 5-8 days. The results suggest that the Gwynne spillway formation was time-transgressive, and that the drainage of glacial Lake Edmonton was largely erosional.

  • Subjects / Keywords
  • Graduation date
    Spring 2022
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.