Download Geology 100

Earth Science 100
Preparation for Exam 2
These study questions are designed to help you review the concepts presented in
class. You should refer to both your class notes and the textbook when answering the
questions. Remember to review any concepts presented as in-class activities or as
homework assignments! This exam focuses on material from Chapters 7 and 8, with a
minor amount of material from Chapter 9. However, some concepts from Plate Tectonics
do either overlap or form the foundation for the concepts covered here!
Chapter 7 – Minerals
1. What is the definition of a mineral? (Remember that there are 4 parts to the
definition.)
2. How is a "rock" different from a "mineral"?
3. What controls chemical bonding? What is the difference between "ionic",
"covalent", and "metallic" bonding?
4. What are the 2 most abundant elements in the continental crust?
5. The silicate mineral group is sub-divided into 2 groups. What are the 2 groups
called and how are they different from each other?
6. There are several mineral groups in addition to the silicates. What criteria are
used to divide the minerals into different groups?
7. What determines the physical properties of minerals?
8. What is the difference between crystal form, cleavage, and fracture?
9. What is the difference between luster, color, and streak?
10. What is meant by mineral "hardness" and how is hardness measured?
Chapter 7 (continued) – Rocks (including some material on weathering from Chapter 9)
1. What is the “Rock Cycle”?
2. What is the definition of an "igneous" rock?
3. What 2 criteria are used to classify igneous rocks?
4. What is meant by the "texture" of an igneous rock and how can this be used to
determine cooling history?
5. In the classification of igneous rocks, what is the different between "felsic" and
"mafic" rocks? Name a classic example of each.
6. In the classification of igneous rocks, what is the difference between "volcanic"
and "plutonic" rocks?
7. What defines a "metamorphic" rock? What are the 3 "agents" of metamorphism?
8. What is the difference between "contact" and "regional" metamorphism?
9. What is the difference between "low grade" and "high grade" metamorphism?
10. What is the difference between "foliated" and "non-foliated" metamorphic
texture? Give a classic example of each.
11. What is "mechanical" weathering? What are some examples of mechanical
weathering?
12. What is "chemical" weathering? What are some examples of chemical weathering?
13. What are the 2 main categories for classifying "sedimentary" rocks? Give some
examples of common sedimentary rocks from each category.
14. Sedimentary rocks provide important evidence for deciphering Earth's history.
What 2 features of sedimentary rocks are crucial in providing this evidence?
Chapter 8 – Geologic Time
1. What are the two basic types of ages that may be determined for geologic events?
2. What is the basic concept behind the "Principle of Superposition"?
3. Briefly explain how the concepts of "original horizontality" and "cross-cutting
relationships" may be used to place geologic events in relative order.
4. What is the definition of a "fossil"? Why are fossils geologically important?
5. What characteristics must a fossil have in order to be a good "index fossil"?
6. Applying absolute ages to geologic time required the use of radiometric dating
techniques. Define the terms "isotope", "radioactivity", "parent", "daughter", and
"half-life" as they pertain to radiometric dating.
7. What are the potential sources of error when using radiometric dating techniques?
Can all types of geologic materials be subjected to radiometric dating techniques?
8. What are the basic subdivisions of time used in the Geologic Time Scale?
9. What does the term "phanerozoic" mean and how does it apply to the Geologic Time
Scale?
10. List the era, period, and epoch in which we currently live.