Chapter 5 and 6 Study Guide Keys
Study Guide – Chapter 5 – Igneous Rocks
Section 5.1 What are igneous rocks?
1. magma
2. igneous rock
3. lava
4. basaltic
5. rhyolitic
6. true
7. false
8. true
9. true
10. false
11. true
12. As the pressure on a rock increases, its melting
point increases.
13. No; different minerals have different melting
points.
14. Temperature increases with depth in Earth’s
crust.
15. Pressure increases with depth from the weight
of overlying rock.
16. melting points
17. partial melting
18. elements
19. reverse
20. fractional crystallization
21. magma
22. discontinuous reaction series
23. continuous reaction series
24. calcium
25. sodium
26. When magma cools rapidly, the calcium-rich
cores are unable to react completely with the
magma, resulting in a zoned crystal with sodiumrich outer layers and calcium-rich cores.
27. At the end of magma crystallization, the
remaining melt, which is enriched with silica and
oxygen, finally crystallizes, forming quartz.
Section 5.2 Classification of Igneous Rock
1. ultrabasic
2. intermediate
3. granitic
4. basaltic
5. ultrabasic
6. basaltic
7. intermediate
8. basaltic
9. granitic
10. ultrabasic
11. Obsidian has a very small grain size.
12. Obsidian is extrusive; its glassy texture without
obvious grains probably formed as lava cooled
quickly on Earth’s surface.
13. Gabbro has large crystals, in contrast to
obsidian’s crystals, which are very small.
14. Gabbro is intrusive; its large grains probably
formed as magma cooled slowly below Earth’s
surface.
15. c.
16. d
17. b
18. e
19. f
20. a
21. to observe the shapes of mineral grains
22. Intrusive igneous rock cools slowly beneath
Earth’s surface, while extrusive igneous rock cools
rapidly at or near Earth’s surface.
23. They have space in which to grow freely.
24. Porphyritic rocks are characterized by large,
well-formed crystals surrounded by finer-grained
crystals.
25. Porphyritic textures can form if a slowly cooling
magma suddenly begins cooling rapidly.
26. d
27. a
28. c
29. b
30. a
31. c
32. a
33. d
34. b
Chapter 5 and 6 Study Guide Keys
Chapter 6 Study Guide – Sedimentary &
Metamorphic Rocks
Section 6.1 Formation of Sedimentary Rocks
1. Sediment
2. unsorted deposits
3. chemical weathering
4. cementation
5. clastic sediments
6. sedimentary rock
7. deposition
8. lithification
9. physical weathering
10. sorted deposits
11. false
12. true
13. false
14. true
15. false
16. false
17. true
18. true
19. bedding
20. transport
21. graded bedding
22. cross-bedding
23. sand dunes
24. ripple marks
25. fossils
26. lithification
Section 6.2 Types of Sedimentary Rocks
1. clastic
2. clastic
3. biochemical
4. biochemical
5. clastic
6. chemical
7. chemical
8. clastic
9. chemical
10. biochemical
11. Shells from dead sea animals settle to the
bottom of the ocean and form sediments. During
burial and lithification of these sediments, calcium
carbonate precipitates out of water and crystallizes
between grains of carbonate sediment, forming
limestone.
12. Fossils provide information about living things
that existed in the past.
13. Some sedimentary features indicate the location
and direction of flow of ancient rivers, the wave
direction over lakes, and ancient shoreline positions.
Section 6.3 Metamorphic Rocks
1. a
2. d
3. g
4. f
5. e
6. b
7. c
8. low, intermediate, and high grades
9. intermediate and high grades
10. low grade
11. a
12. b
13. b
14. d
15. c
16. c
17. d
18. a
19. a
20. igneous rocks
21. sedimentary rocks
22. metamorphic rocks
23. Igneous rocks cool and crystallize from magma.
24. The igneous rocks become sediments.
25. Sediments undergo deposition, burial, and
lithification to become sedimentary rock.
26. heat and pressure
27. Possible response: The metamorphic rock can
melt to form magma that cools and crystallizes
to form igneous rock.
28. The sandstone can be uplifted, weathered, and
eroded to form sediments.