EXERCISE 1.8: How Long Do Processes in the Earth System Take? The following questions will give you a sense of the rates at which uplift and erosion take place. We will assume that uplift and erosion do not occur at the same time—that mountains are first uplifted, and only then does erosion begin—whereas the two processes actually operate simultaneously. Part 3.a. Evidence shows that there were once Himalayan-scale mountains in northern Canada, in an area now eroded nearly flat. If the Earth were only 6,000 years old, as was once believed, how fast would the rate of erosion have had to be for these mountains to be eroded to sea level in 6,000 years? Give your answer in meters and millimeters.