Relative and Absolute Age Dating Review

The statement "Intrusion B occurred after the deposition of layer E but after deposition of layers C, D, and A" can be determined to be correct because of which principle?

• Principle of Horizontality

• Principle of Cross-Cutting Relationships

• Principle of Inclusions

• Principle of Superposition

Answer explanation

The statement is correct due to the Principle of Superposition, which states that in an undeformed sequence of sedimentary rocks, younger layers are deposited on top of older layers. Thus, Intrusion B must be younger than layers E, C, D, and A.

The statement that the oldest layer will be at the bottom in an undisturbed sequence of rock layers is called the Principle of ....

• Inclusions

• Unconformities

• Cross-Cutting Relationships

• Superposition

Answer explanation

The Principle of Superposition states that in an undisturbed sequence of rock layers, the oldest layer is at the bottom and the youngest is at the top. This principle is fundamental in geology for dating rock formations.

The Principle of Cross-Cutting Relationships states that an igneous intrusion is 

• always younger than the layers it cuts across

• always older than the layers it cuts across

• the same age as the rock it melted

• none of the answers are correct

Answer explanation

The Principle of Cross-Cutting Relationships states that an igneous intrusion must be younger than the rock layers it cuts across, as it disrupts those layers. Therefore, the correct answer is that it is always younger than the layers it cuts.

Relative age dating is used to determine the...

• actual age of an event

• length of time between two events

• age of one event in comparison with other events

• rate at which a gologic process occurs

Answer explanation

Relative age dating determines the age of one event in comparison with other events, helping to establish a sequence of geological events without providing exact dates.

Older rocks contained within newer rocks are called...

• intrusions

• inclusions

• fossils

• faults

Answer explanation

Older rocks contained within newer rocks are called inclusions. This term refers to fragments of older rock that are incorporated into a newer rock formation, distinguishing them from other geological features like intrusions or fossils.

Which of the following correctly lists the layers in order from oldest to youngest?

• A, B, C, D, E

• E, B, C, D, A

• E, D, C, B, A

• C, B, A, D, E

Answer explanation

The correct order from oldest to youngest is E, B, C, D, A. This sequence reflects the geological principle of superposition, where lower layers are older than those above them.

How old is the Earth?

• 4.6 billion years

• 1.4 billion years

• 4.6 million years

• 6000 years

Answer explanation

The Earth is approximately 4.6 billion years old, based on radiometric dating of the oldest rocks and meteorites. The other options are significantly younger and incorrect.

What is the oldest layer in the outcrop?

• B

• C

• D

• E

Answer explanation

Layer E is the oldest because, in geological formations, the principle of superposition states that lower layers are older than those above them. Therefore, E, being at the bottom, is the oldest layer in the outcrop.

What is the youngest layer in the outcrop?

• A

• B

• C

• D

Answer explanation

Layer A is the youngest because, in geological terms, the most recent deposits are found on top of older layers. Therefore, it is the last layer formed in the outcrop.

The statement "Layer B is younger than layer E" can be determined by using which principle?

• Principle of Horizontality

• Principle of Cross-Cutting Relationships

• Principle of Inclusions

• Principle of Superposition

Answer explanation

The statement "Layer B is younger than layer E" is determined by the Principle of Cross-Cutting Relationships, which states that a geological feature that cuts through another is younger than the feature it disrupts.