In the upper 10 km of the crust, the geothermal gradient is typically about 25C per km, but it can range from 15C/km to 50C/km. In the chart below, plot these three geothermal gradients (15C/km, 25C/km, and 50C/km) for the upper 10 km of the Earth. Use one line for each gradient. 0 1 Depth (km) 7 8 2 3 4 9 10 50 100 150 200 250 Temperature (C) 300 350 400 450 500 . The deepest mine on Earth penetrates to a depth of about 2 km. Using the geothermal gradients you just drew, what range of temperatures would you expect in the mine? Explain your answer. How hot is it in the bottom of this mine? What assumptions did you make to come up with this answer?