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USGS CMG InfoBank: Ice Wedging

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Comment: 04:38 - 05:41 (01:03)
Source: Annenberg/CPB Resources - Earth Revealed - 15. Weathering and Soils
Keywords: "ice wedging", weathering, "mechanical weathering", water, volume, pressure, granite

Our transcription: For example, "ice wedging".
When water freezes, its volume expands as much as 9%.
This expansion exerts enormous pressure, as those acquainted with bursting water pipes in winter well know.
We also see the effect of this pressure on roads in cold climates.
After a particularly frigid winter, the water that has seeped under the pavement freezes and expands, heaving up the road surface.
The same thing happens to rocks.
When water gets into the cracks and freezes, it expands, wedging the rock apart, extending the crack and even breaking the rock into pieces -- which is what happened to form these jagged spires of granite.

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