Relative Dating

The layers and layers of rock that make up the Earth’s crust are like the Earth’s personal diary. Geologists are capable of “reading” these layers and find out what happened in the past to create the rocks that are exposed at the surface. In addition to gaining insight to Earth’s history, geologists can determine relative ages for the rock layers. Relative dating techniques provide general ages for layers of rock without using specific numerical values. Geologists pay close attention to the arrangement and positions of the rocks that are exposed. Then, using the law of superposition, the law of original horizontality, and the law of cross-cutting relationships, geologists can effectively determine the oldest and youngest rocks in a rock outcrop without any laboratory tools.