Evidence About Earth’s Past (Book)


- Cross-Cutting Relationships

Rock layers may have another rock cutting across them, like the igneous rock in Figure. Which rock is older? To determine this, we use the law of cross-cutting relationships. The cut rock layers are older than the rock that cuts across them.

Cross-cutting relationships in rock layers


Cross-cutting relationships in rock layers.
Rock D is a dike that cuts across all the other rocks. Is it older or younger than the other rocks?