Earth History

If an index fossil is found in two rock layers that are separated by an ocean, what do you know about the relationship between the two rock layers?

• they are about the same age
• both areas were dry
• the are made of the same kind of rock
• the rock layers are unrelated

Which type of dating method can be used on rock layers by applying the Law of Superposition?

• relative dating
• absolute dating
• radioactive dating
• radiometric dating

Gaps in rock layers caused by erosion are called.

• law of superposition
• unconformities
• uniformitarianism
• relative dating

What things make a good index fossil?

• Good looks and a great smile
• widespread and on Earth of a short time
• widespread and on Earth for a long time
• Only found in one location and in every layer

Which of the following is the oldest?

• Layer L
• Intrusion D
• Intrusion H
• Layer E

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

Which best describes radiometric dating?

• using instruments that detect radioactivity to figure out how old something is
• measuring the relative amounts of a radioactive isotope and a daughter product to figure out the age of a sample
• measuring how quickly the different radioactive isotopes in a sample decay to figure out the age of the sample
• using short-wavelength electromagnetic radiation to determine the age of a sample

The length of time required for half of the radioactive atoms in a sample to decay is its...

• era
• age
• half-life
• eon

Scientists use radioactive decay to measure...

• relative time
• absolute time
• half-lives
• time of day

Which element is usually used to date rocks?

• Carbon-14
• Nitrogen-12
• Uranium-238
• Oxygen-18