Contents of 7.3 How do geologists determine the relative ages of rocks in widely separated places?

7.3 How do geologists determine the relative ages of rocks in widely separated places?

Principle of Lateral Continuity - layers are continuous until encountering an obstruction

Image of the Grand Canyon and drawiings showing lateral continuity.

Diagrams showing an interpretation in applying principles of lateral continuity shows a cross section of the Grand Canyon and various layers.

Here at the Grand Canyon, we can see that layers continue for large expanses, but are broken (cross-cut) by the canyon itself.

Fig 7.6