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How do glaciers carve and deposit continental landforms?

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continental landform Davis's proposed landscape-development states. The morphology shown is not actually time-indicative. For example, A could be a gully system in soft sediment or a canyon such as the Royal Gorge in Colorado, which is millions of years old. The ridge-ravine topography of B would normally develop under humid conditions, but the river meandering on alluvium indicates a prior or extraneous non-humid aggrading mechanism. The riverine plain of C implies a complex history of planation and aggradation in a current fluvial mode.

Glaciers carve and deposit continental landforms through processes concentrated at their base and margins.1

Glacial Erosion

Glaciers erode their substrate primarily through two mechanisms:
* Abrasion: Acting like sandpaper, glaciers use rock debris embedded in their basal ice to scratch, polish, and gouge the underlying bedrock. This process creates streamlined features such as roches moutonnées and rock drumlins.23
* Plucking (Quarrying): Glaciers remove larger blocks of bedrock by exploiting fractures and joints, often aided by pressure changes and the refreezing of meltwater.2

Unlike streams, glaciers can flow uphill, allowing them to scour deep basins and depressions, many of which now contain lakes. In areas of high relief, they can carve deep, U-shaped troughs, which may become fjords if later submerged by the ocean.3

Glacial Deposition

As ice velocity decreases near the glacier margin, debris is deposited as glacial drift:4
* Till: Material deposited directly by ice, forming features like ground moraine (a thin, hummocky sheet of sediment) and drumlins (elongated, streamlined mounds).54
* Moraines: Linear ridges of debris, such as end or terminal moraines, mark the ice margin at various stages of retreat.51
* Outwash: Meltwater streams rework debris into stratified, sorted deposits in front of the glacier.4