6.4 Mastery 1 - Law of Superposition

Superposition means that in an undisturbed sequence of sedimentary rocks, which of the following is true?

• The oldest rocks are on top

• The youngest rocks are on top

• The youngest rocks are in the middle

• There is no way to know which layers are older

Using the law of superposition, order these rocks from oldest to youngest. Mark only one oval.

• CBAD

• DABC

• ABCD

• CDAB

The diagram shows fossils in different rock layers. Which of these statements about the age of these fossils is most likely correct?

• Fossil 2 and 4 are the same age

• Fossil 2 is older than fossil 3

• Fossil 1 and 3 are the same age

• Fossil 4 is older than fossil 3

Which layer formed first? Refer to the diagram showing rock layers labeled R, F, M, B, I, and H. Mark only one oval.

• B

• R

• I

• H

Which fossil is the oldest? Refer to the diagram for fossil locations in rock layers.

• Trilobite

• Ammonite

• Crinoid

• Gastropod

Which layer would be considered a magma intrusion? Mark only one oval.

• H

• M

• F

• I

What is the oldest rock layer in this picture? Mark only one oval.

• D

• A

• E

• B

Which fossils are older than fossil C? Mark only one oval.

• A and B

• D, E, and F

• Only B

• Only A

The magma intrusion is the newest rock layer in the diagram.

• True

• False

True or False: The Fern is the newest fossil in the diagram. Mark only one oval.

• True

• False