EARTH SCIENCE - CHAPTER 6 STUDY GUIDE
WORDS TO KNOW
Relative dating
Superposition
Geologic column
Unconformity
Absolute dating
Isotopes
Radioactive
decay
Radiometric
dating
Half-life
Fossil
Permineralizatio
n
Petrification
Trace fossil
Coprolite
Mold
Cast
Index fossil
Geologic time
scale
Eon
Era
Period
Epoch
INFORMATION TO KNOW
 Know the 4 ways rock layers can be disturbed: folding, faulting,
tilting and intrusions. Be able to recognize illustrations
 Know the 3 types of unconformities: non-conformities,
disconformities, and angular unconformities. Be able to
recognize illustrations.
 Know how unconformities form.
 Know what the geologic column is. You will have rock layers
similar to the one in our class activity (pg 652) and will have
to arrange them into matching layers.
 Know what an isotope is and why it can be used to date rocks.
 Know how to determine the number of atoms remaining of parent
and daughter material after a certain number of half lives. See
the chart on page 143 for an example.
 Know the 3 types of radiometric dating (Carbon 14, PotassiumArgon, and Uranium-Lead). Know which you would use for the
youngest rocks and which you would use for the oldest rocks.
 Know 5 ways in which fossils can form. Know the details of how
these methods form fossils.
 Know some examples of trace fossils.
 Know how fossils can be used to help us understand the past (pgs
149-150)
 Know the divisions of geologic time (eons, eras, periods and
epochs). Know specifically the 4 eons in order and the 3 eras in
order.
 Know which eon, era, period, and epoch you are living in.
PRACTICE ESSAYS
1. Describe the 4 ways rock layers can be disturbed. Include
illustrations and captions with complete sentences.
2. Give at least 3 things we can learn from fossils. Consider the
location, position, and abundance of the fossil when answering.
3. A mummified human is found in the Sahara desert. About 12.5% of
the carbon in the mummy is Carbon 14. Explain how you can find
the mummy’s age.
4. Out in the badlands, you notice an igneous intrusion in some
sedimentary rock. Without testing the rock, can you tell if the
igneous intrusion is older or younger than the sedimentary rock?
How do you know?
5. Scientists know that tropites existed only for about 20 million
years, which is a very short period of time for an organism. How
could scientists use this information?