Formation of the Viking Moraine, east-central Alberta: Geomorphic and sedimentary evidence

Inferring the genesis of glaciogenic landforms is often difficult. The combination of limited or lacking sedimentologic data and the likelihood of process continua makes many interpretations tenuous. It is therefore necessary to investigate not only the sediments contained in the landforms but also their topographic setting, geomorphic characteristics, and association with other landscape elements. This thesis incorporates the analysis of geomorphic and sedimentary characteristics at several scales to infer the formation of part of the Viking Moraine in east-central Alberta. Visualization of landform shapes and associations is greatly aided by the incorporation of shaded relief maps derived from digital elevation models (DEMs).; On a regional scale, landforms are arranged into packages which suggest that widespread erosion was instrumental in isolating the different landform suites. This erosion is interpreted to have been performed by catastrophic discharges of subglacial water. At least one subglacial flood initially occurred as a sheetflow but it was progressively channelized due to the instability of the flow and the spatially variable erosion of the basal ice and subglacial material. Investigation of individual landforms within the Viking Moraine substantiates this interpretation in terms of their topographic, geomorphic, and sedimentologic characteristics. Erosional channels have convex-up long profiles and contain hummocky terrain composed of bedrock and glaciogenic material. The presence of glaciogenic material in some channels indicates that the channels preexisted the erosion. Hummocky terrain is composed of stacked subglacial sediment, horizontally banded diamicton, and/or bedrock. The complement of different sediment types indicates a complex history of entrainment and deposition that reflects temporally dependent polythermal basal conditions. The combination of complex thermal conditions at the base of the ice and erosion by subglacial water best explains the emplacement and subsequent erosion of the subglacial materials found in this part of the Viking Moraine.