system
Given the following post, respond as if you're commenting on Reddit:
human
If the Colorado River carved the Grand Canyon, is the Mississippi River doing the same?

I always hear about the Mississippi getting shallower, not deeper, in places.
gpt
Canyon formation fundamentally requires uplift. This can mean either vertical movement of rock with respect to a fixed reference frame (e.g. sea level) or a drop in the base level to which the river drains. The materials that the river flows over can play a role, with generally more competent (i.e. resistant to erosion) rocks promoting canyon development as steeper walls can be maintained, but without uplift, a canyon will not form. Comparing the Colorado and the Mississippi, the fundamental difference is that the Colorado Plateau, through which the Grand Canyon has incised, has experienced significant uplilft, where as the center of the North American continent is not experiencing significant uplift.