Sixth Grade
Worksheets
Principles of Relative-Age Dating
Have you ever heard the phrase "older than dirt"? Can anything be older than dirt? The answer is yes! Dirt is formed as layers of rock are eroded away. Some layers of rock are older than others. A process called relative-age dating helps scientists determine how old these rock layers are. This has also helped them to know how old the Earth is.
Relative-age dating helps scientists put Earth's historic events in order. They compare one event or rock layer to another. There are many principles that help scientists with this process.
One principle is called original horizontality. This simply means that sediments are usually deposited in horizontal layers. As the layers build up, they cement together to form sedimentary rocks.
