According to White, Harrison and Mottershead (1992), glacial deposition involves two main activities; the first being the release of debris as the ice masses ablate the bedrock and its surficial components, and two, the distribution or reorganization of debris by falling and flowing glacial components and meltwater (Chorley, Schumm & Sugden, 1985). Along this line, the nature of deposition is affected at the point at which the debris is released from the ice. Release of debris as the ice masses ablate the bedrock and its surficial components
Pressure is usually created below an actively sliding glacier, thereby causing the resultant meltwater to release the glaciers components. The released particles then become plastered to the bedrock surface to form a lodgment till (White, Harrison and Mottershead, 1992). However, in cases where the glacier is stagnant, the process of sub-glacial melting due to geothermal heating causes mineral debris to accumulate in the glacier bed (White, Harrison and Mottershead, 1992).
Further melting of the glacier surface due to heating by solar energy causes the formation of more meltwater and this causes more debris to be deposited with the meltwater (Martini, Brookfield & Sadura, 2001). The orientation of the glacier bed determines the nature of deposition caused by ice. If the glacier bed is sloppy, this indicates that the debris carried by a glacier is likely to be moved a longer distance than it would in a plain. The deposited material may be saturated with the ensuing meltwater and be moved further as till flow (Martini, Brookfield & Sadura, 2001).
This process causes further deposition of debris as the moving force of the meltwater declines. Meltwater deposition is pivotal in the deposition of mineral components of the glacier debris and other fluvioglacial contents (White, Harrison and Mottershead, 1992). Deposition by meltwater is affected by several factors such as the fluctuating nature of meltwater discharge, which is pegged on daily temperature variations; and the physical constraints (obstructions) in the path of the glaciers.
These include other glaciers, faults and other slumping structures (Chorley, Schumm & Sugden, 1985). Reorganization of debris by falling and flowing glacial components and meltwater The depositional activities involved in reorganization of debris by falling and flowing glacial components include sliding, slumping, debris flowage and turbidity flowage (Hambrey, 1994). As the displacement of glaciers occurs, the presence of meltwater causes more sliding that eventually results into internal deformation.
Slumping involves internal folding and displacement of debris as more and more glacial components are deposited. This is accompanied by debris flowage that involves the reorganization and mixing of glacier constituents such as silt that move as a slurry, thus being deposited over vast areas. As the sediments move, there is a tendency of loose and suspended sediments being deposited on the sides of the glaciers path (turbidity flow), leading to the formation of graded beds that are characteristic of the Saskatchewan landscape (Hambrey, 1994).
Although not much literature is available about the particular depositional processes involved in Saskatchewan glaciers, the above discussion gives an overview of what happened and still happens in the formation of glacial features in the region. Glacial erosion and deposition are dynamic processes that still continue to shape the surficial geology of Saskatchewan. Conclusion The surficial geology of Saskatchewan has been impacted upon largely by glaciation. This has led to the formation of a multiplicity of landforms in the region such as drumlins, megaflutes, misfit streams, ice marginal moraines and so forth.
Most of these features were formed under Quaternary glacial activities. Two wide depositional processes are responsible for the formation of depositional landforms in Saskatchewan. One is the release of debris as ice masses ablate the underlying bedrock and two, the reorganization of glacial components and meltwater, which cause variation in the points and nature of deposition.
Ber, A. (2007). Glaciotectonism. New York: Elsevier Canadian Glacier Inventory Project. Saskatchewan Glacier. Retrieved 2 April 2009, from http://geoconvention.org/