Relative Dating Principles 1: Lower strata are older than those lying on top of them. Principle of Superposition: In an otherwise undisturbed sequence of sedimentary strata, or rock layers, the layers on the bottom are the oldest and layers above them are younger.

What are the three major types of unconformities?

Commonly three types of unconformities are distinguished by geologists:ANGULAR UNCONFORMITIES.DISCONFORMITIES.NONCONFORMITIES.