6. Using the diagram, which rock layer
likely formed first?
_____________________________
Relative Dating Practice
1. Using the diagram, determine what sequence
of events occurred in the rock layers shown
above.
A. An intrusion formed, and then the rock
layers formed around the intrusion.
B. First, the bottom layer of rock layers
formed. Then, the intrusion formed. Finally,
a fault cut through the top layers.
C. The rock layers were folded, and then the intrusion cut through the layers.
D. All of the rock layers formed, and then an intrusion cut through some of the
layers.
7. What law tells you this layer formed
first? ___________________________
_____________________________
8. Which rock likely formed last?
_________________________________
9. What law tells you this? ________________________________________________
Using the diagram circle the correct answer, or fill in the blanks.
10. Fossils in layer Y are likely
__older/younger__ than fossils
found in rock layer X.
2. Using the diagram above, put the rock layers in order from the oldest (first to
occur), to the youngest (last to occur). Use textbook page 243 if you need help.
First rock ___________ formed, next rock ____________ formed second, then rock
____________ formed third, and lastly rock ____________ formed.
3. The law of _____________________________ says that an intrusion is always
younger than the rock that it cuts through.
4. The law of ____________________________ says the older rocks lie below
younger rocks in undisturbed layers.
5. If two fossils are found in the same undisturbed rock layer, how will their ages
compare? ____________________________________________________________
11. The intrusion, labeled by
letter ______ is
__older/younger__ than the
rock layers that it cuts through. I
know this because of the law of
__superposition/cross-cutting
relationships__ says _________
______________________________________________________________________
12. Find the picture of the ammonite fossil. The ammonite fossil is found in rock layer
__________. This rock layer is __older/younger__ than rock layer Z. The law of
__superposition/cross-cutting relationships__ tells me that this is true because it says
_______________________________________________
13. If the fossils in layer Y formed 100 million years ago, and its ancestors formed 200
million years ago, which rock layer would contain the fossils of the ancestor species?
________________ How do you know? _____________________________________
______________________________________________________________________