Chapter 3 - Relative-Age Dating

Front

What is relative age dating?

Back

Relative age dating is a method used to determine the age of rock layers and fossils in relation to one another, without determining their exact age.

Front

What is the principle of superposition?

Back

In an undisturbed sequence of rock layers, the youngest rocks are on top and the oldest rocks are on the bottom.

Front

Why is the Law of Superposition important?

Back

It helps in determining the relative ages of rock layers.

Front

What are index fossils?

Back

Index fossils are fossils of organisms that were widespread but existed for only a short period of time, used to determine the relative age of rock layers.

Front

What does the principle of inclusions state?

Back

The inclusions found in a rock layer are older than the rock layer itself.

Front

What is the principle of original horizontality?

Back

This principle states that layers of sediment are originally deposited horizontally under the action of gravity.

Front

What are cross-cutting relationships?

Back

Cross-cutting relationships state that if a rock or fault cuts through other rocks, it must be younger than the rocks it cuts through.

Front

How do geologists use fossils in relative age dating?

Back

Geologists use fossils to correlate rock layers and determine their relative ages based on the types of fossils present.

Front

What is an unconformity?

Back

An unconformity is a gap in the geological record that represents a period of erosion or non-deposition.

Front

What is the significance of sedimentary rock layers?

Back

Sedimentary rock layers provide a record of Earth's history, including past environments and life forms.