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Chapter 16 - Igneous Rocks & Volcanoes [print-friendly version]
1. Molten rock which intrudes the crust is called _______________________.
2. Molten rock which extrudes on to the surface is called ______________________.
3. Intrusive rocks cool at great depth in the crust and therefore form interlocking crystals which are _______________ , while extrusive rocks cool on the surface and are __________________.
4. Complete table.
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Grain Size |
Rate Of Cooling |
Examples |
| Plutonic |
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| Volcanic |
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5. Two features that characterise igneous rocks are that they have interlocking crystals and are ______________.
6. Igneous rocks are rocks that have formed from the crystallisation of ______________ or _________________.
7. Use the following table to distinguish between lava and magma.
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Lava |
Magma |
| Where found? |
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| Gas content? |
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| Types of rocks formed on cooling? |
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| Examples of rocks? |
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8. Two types of volcanoes are ____________________ and ___________________.
9. Complete the table
| Type of Volcano |
Explanation/Definition/Examples |
Labelled diagram |
| Shield Volcano |
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| Composite Volcano |
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10. What is a cone? ________________________________________________________________ ________________________________________________________________________________
11. How do the following terms applied to volcanoes differ in meaning? Active Dormant Extinct
12. A ________________ is a deep narrow geological feature with its depth > 3 x its width.
13. A ________________ is a shallow, wide geological feature with its depth < 3 x its width.
14. What are some indications of an eruption? __________________________________________ ________________________________________________________________________________
15. Complete the following table.
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Quiet Eruptions (Hawaiian-type) |
Explosive Eruptions |
| Viscosity of lava |
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| Gas content of lava |
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| Composition of lava(rocks formed) |
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| Associated features |
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| Type of volcano produced |
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| Examples of volcanoes |
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Multiple choice quiz
- Which of the following types of igneous rocks is a volcanic extrusive rock?
| a. gabbro |
b. andesite |
c. diorite |
d. granite |
- Which of the following types of igneous rocks is a plutonic intrusive rock? (intrusive) rock
| a. rhyolite |
b. basalt |
c. trachyte |
d. gabbro |
- What do we call an igneous rock composed of a disordered (amorphous) structure that has cooled so quickly that no crystals have formed?
| a. fine-grained |
b. glass |
c. coarse-grained |
d. granite |
- Refer to your classification tables in your booklet. Which term describes the composition of basalt?
| a.felsic |
b. fine-grained |
c. mafic |
d. intermediate |
- Which term describes the composition of granite?
| a. felsic |
b. coarse-grained |
c. mafic |
d. intermediate |
- Which rock is the fine-grained equivalent of granite?
| a. andesite |
b. basalt |
c. obsidian |
d. rhyolite |
- Which rock is the coarse-grained equivalent of basalt?
| a. diorite |
b. gabbro |
c. granite |
d. pumice |
- Which of the following rocks ontains the most quartz?
| a. andesite |
b. basalt |
c. obsidian |
d. rhyolite |
- Which of the following rocks contains the least silica and no free quartz?
| a. diorite |
b. gabbro |
c. granite |
d. rhyolite |
- Which of the following rocks is pyroclastic?
| a. diorite |
b. gabbro |
c. granite |
d. tuff |
- What factor primarily controls the viscosity, and therefore the explosiveness, of a magma?
| a. Dissolved gases |
b. pressure |
c. silica content |
d. temperature |
- Which type of volcano is large and has a low slope, such as the Hawaiian volcanoes?
| a. Composite cone |
b. Cinder cone |
c. caldera |
d. shield volcano |
- Which type of volcano is high and steep, such as Mount St. Helens and mount Fuji?
| a. Composite cone |
b. Cinder cone |
c. caldera |
d. shield volcano |
- Which type of volcano is composed of alternate lava flows and pyroclastic material (ash)?
| a. Composite cone |
b. Cinder cone |
c. caldera |
d. shield volcano |
- What is formed when a magma chamber is severely depleted and the volcano subsides into the empty space?
| a. Composite cone |
b. Cinder cone |
c. caldera |
d. shield volcano |
- Shield volcanoes are usually composed of:
| a. andesite |
b. basalt |
c. gabbro |
d. rhyolite |
- A well known example of an extinct and well-eroded shield volcano in SE Qld is
| a. Mount Warning |
b. Mount Beerburrum |
c. Mount Coot-tha |
d. Mount Gravatt |
- What type of volcano is associated with a subduction zone?
| a. Composite cone |
b. Cinder cone |
c. caldera |
d. shield volcano |
- What rock type is produced at divergent plate boundaries (spreading centres)?
| a. andesite |
b. basalt |
c. granite |
d.rhyolite |
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