The number that Colorado River would have to downcut per year to form the mile-deep canyon in 4 million years is 0.40 millimeter per year.
Depth of canyon = 1 mile
Time taken = 4 million years
Based on the above information, the rate will be:
= Depth / Time taken
= 1 mile / 4 million years
= 0.25 mile / million year
Note tha<em>t 1 mile = 1609344 millimeter</em>
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Therefore, the rate will be:
= (0.25 × 1609344) / 1000000 years
= 0.40 millimeter / years
In conclusion, the rate is 0.40 millimeter per year.
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Answer:
The earth's plates move because of the intense heat of the mantle
