This cross section is the final stage of the rifting and formation of a divergent continental margin. It takes about 110 million years to reach this stage, and in the process a wedge of sediments about 14 miles thick accumulates. Notice the old axial rift (with volcano) at the bottom of the pile.
This cross section is color coded to cross sections 1-3 so that you can easily compare them, and see the new rocks that have been added at each stage.
Contributed by Lynn Fichter