Chapter 3 - Relative-Age Dating

Front

What is the principle of cross-cutting relationships?

Back

It states that a rock layer is older than any rock or feature that cuts through it.

Front

What is the Law of Superposition?

Back

Oldest rocks are at the bottom and youngest rocks are at the top.

Front

What are index fossils?

Back

Index fossils are fossils of organisms that were widespread but existed for only a short period of time. They are used to determine the relative age of rock layers by comparing the fossils found in different layers.

Front

What does the principle of original horizontality state?

Back

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

Front

Why is the Law of Superposition important?

Back

It helps in determining the relative ages of rock layers.

Front

What is relative age dating?

Back

Relative age dating is a method used to determine the age of rocks and fossils in relation to one another.

Front

What is an example of an index fossil?

Back

An example of an index fossil is the trilobite, which was widespread but existed for a relatively short time.

Front

How do geologists use the principle of original horizontality?

Back

Geologists use this principle to infer that if sedimentary layers are found tilted or folded, they were disturbed after their original deposition.

Front

What is the significance of fossils in relative age dating?

Back

Fossils help to correlate the ages of rock layers and provide evidence of the environmental conditions at the time of deposition.

Front

What is the difference between relative age dating and absolute age dating?

Back

Relative age dating determines the order of events, while absolute age dating provides a specific age or date for an event.