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Cordillera ProvincesGeology of National Parks

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Rocky Mountain System

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Isostasy At Work

• Isostasy states that differences in elevation are compensated for by low-density roots

• Imagine a sponge floating in water Part of the sponge floats above the level of the

water-it has positive elevation Compensating that elevation is a low-density

root-the portion of the sponge below the water (sponge is less dense than water)

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Isostasy

• Wood block is denser than foam, so more of the wood is submerged

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Loading and Unloading

• Crustal loading, as by ice, water, sediments, or volcanic flows, leads to isostatic depression or downwarping; removal of load, to isostatic uplift or upwarping