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If a glacier's terminus moves forward faster than it melts, the net result is advance. Glacier retreat occurs when more material ablates from the terminus than is replenished by flow into that region. Glaciologists consider that trends in mass balance for glaciers are more fundamental than the advance or retreat of the termini of individual ...
Abrasion leads to steeper valley walls and mountain slopes in alpine settings, which can cause avalanches and rock slides, which add even more material to the glacier. Glacial abrasion is commonly characterized by glacial striations. Glaciers produce these when they contain large boulders that carve long scratches in the bedrock.
As glaciers move over their beds, they entrain and move material of all sizes. Glaciers can carry the largest sediment, and areas of glacial deposition often contain a large number of glacial erratics , many of which are several metres in diameter.
A glacier stream is a channelized area that is formed by a glacier in which liquid water accumulates and flows. [1] Glacial streams are also commonly referred to as "glacier stream" or/and "glacial meltwater stream". The movement of the water is influenced and directed by gravity and the melting of ice. [1]
Plucking is increased where there are preexisting fractures in a rock bed. As the glacier slides down a mountain, energy from friction, pressure or geothermal heat causes glacial meltwater to infiltrate the spaces between rocks. [4] This process, known as frost wedging, puts stress on the rock structure as water expands when it freezes.
A glacier is an extended mass of ice formed from snow falling and accumulating over a long period of time; glaciers move very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of accumulation, as in continental glaciers.
Multiple erratics on the terminal moraine of the Okanogan Lobe. The Cascade Mountains are in the background.. The term "erratic" is commonly used to refer to erratic blocks, which geologist Archibald Geikie describes as: "large masses of rock, often as big as a house, that have been transported by glacier ice, and have been lodged in a prominent position in the glacier valleys or have been ...
Basal sliding is the act of a glacier sliding over the bed due to meltwater under the ice acting as a lubricant.This movement very much depends on the temperature of the area, the slope of the glacier, the bed roughness, the amount of meltwater from the glacier, and the glacier's size.