Earth and Space Science
The Rock Record
Study Guide
Apply all of the following terminologies to the block diagram that follows:
Law of Crosscutting Relationships
Law of Superposition
Principle of Original Horizontality
Unconformities
Which rock layers demonstrate the Principle of Original Horizontality?
Which rock layers demonstrate the Law of Crosscutting Relationships?
Identify an unconformity. What caused the unconformity?
Identify an inclusion.
Which rock layer is the oldest? Which is the youngest?
Geologic Time Scale
What THREE time Periods comprise the Mesozoic Era?
1.
2.
3.
List TWO species that went extinct at the end of the Mesozoic Era.
1.
2.
Which sequence correctly shows time periods listed from oldest to youngest?
A.
Ordovician – Devonian – Jurassic – Cambrian
B.
Triassic – Permian – Jurassic – Cretaceous
C.
Mississippian – Pennsylvanian – Permian – Silurian
D.
Cretaceous – Paleogene – Neogene – Quaternary
How old is the Earth?
Absolute Time
Key Terms:
Absolute Age:
Varve:
Radiometric dating:
Half-life:
Complete the following table which gives information about the radioactive decay of Carbon-14.
Half - Life Mass or Original Carbon-14 Remaining
Percent Remaining
Number of Years
(grams)
0
50
100
0
1
25
50
5,700
2
3
4
5
6
The diagram below represents a sample of a radioactive isotope.
Sample before decay
Key
Radioactive isotope
Decay Product
For the empty squares below, shade in the proportion of remaining mass after each half-life.
1 Half-life
2 half-life
3 half-life
4 half-life