847262
Descripción
Mapa Mental por Andrew_Ellinas, actualizado hace más de 1 año
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Creado por Andrew_Ellinas
hace casi 10 años
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Cold Environments: Processes in
Glacial Landscapes
- Weathering in a Cold Environment
- Weathering is defined as the breakdown of rock in situ (original
position), at or just below the ground surface
- Frost Shattering/Freeze Thaw: Commonly affects bare rocky outcrops high up on a mountainside.
Water finds its way in between cracks in the rock, the temperature drops to 0 or below and the water
turns to ice. This then causes, what used to be water but is now ice, to expand and crack the rock. The
ice then melt when the temperature raises again.
- Frost shattered rocks are sharp and angular. As they become trapped under the ice, they
prove to be a good abrasive tool.
- Weathering is defined as the breakdown of rock in situ (original
position), at or just below the ground surface
- Glacial Processes
- Abrasion: The sandpapering effect of glacial ice as it moves over the landscape. Striations are carved
out because of this. Over time, the big rocks used to abrade the landscape become pulverized by the
weight of the glacial ice and become fine rock flour.
- Plucking: This occurs when the refreezing of meltwater freezes part of the
underlying bedrock to the base of the glacier. Loosened rock fragments are
'plucked' away when the glacier moves forward.
- A roche mountonnee would have acted like an obstacle to a glacier moving down the
valley. The process of abrasion eroded the stoss side, and the process of plucking eroded
the lee side
- Carbonation: This is the process of chemical weathering that involves the slow dissolving of calcium
carbonate in some rocks-particularly limestone. CO2 dissolved in water forms a weak carbonic acid, which
reacts with calcium carbonate in the rocks to form calcium bicarbonate, which then dissolves. The lower the
temperature, the more effective carbonation will be.
- Abrasion: The sandpapering effect of glacial ice as it moves over the landscape. Striations are carved
out because of this. Over time, the big rocks used to abrade the landscape become pulverized by the
weight of the glacial ice and become fine rock flour.
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