Seismologists indicate that the average thickness of granitic continental crust is about 35 kilometers. Make the same kind of calculation you just completed in section C1, but this time, use the average density you determined for granite to estimate how high granitic continental crust would float in a viscous, flowing upper mantle. Show your work. The upper surface of continental crust in this imaginary world would be about _____ km above the level of the upper mantle.