The relative age of a rock is its age in comparison with other rocks. If you know the relative ages of two rock layers, you know which is older and which is younger, but you do not know how old the layers are in years.

What does relative rock mean?

Relative age means age in comparison with other rocks, either younger or older. The relative ages of rocks are important for understanding Earths history. New rock layers are always deposited on top of existing rock layers. The rock layers at the bottom of this cliff are much older than those at the top.

What is relative age in geology?

1. n. [Geology] The approximate age determination of rocks, fossils or minerals made by comparing whether the material is younger or older than other surrounding material.

What made of relatively younger rocks?

Steno stated that sedimentary rocks are formed in continuous, horizontal layers, with younger layers on top of older layers. A century later, James Hutton discovered the law of cross-cutting relationships: a fault or igneous intrusion is younger than the rocks that it cuts through.

Which is the oldest rock layer?

The principle of superposition states that the oldest sedimentary rock units are at the bottom, and the youngest are at the top. Based on this, layer C is oldest, followed by B and A.