Download Name___________________________ Igneous Rocks Formation

Name___________________________
Igneous Rocks
Formation
1. What three factors determine the type of igneous rock that forms?
Extrusive Igneous Rock
2.
Where does extrusive rock form?
3. At what rate does extrusive rock cool?
4. Why don’t crystals always form in extrusive rock?
5. What happens to the gas in gas-rich lava as it erupts?
6. Which feature of extrusive rock indicates that gases escaped?
Intrusive Igneous Rock
7.
Where does intrusive rock form?
8. At what rate does intrusive rock cool?
9. Why does magma cool at a different rate underground than at the surface?
10. Which type of crystals form in intrusive rock?
11. How are crystals arranged in intrusive rock?
Put a check mark in the space that identifies the correct type of igneous rock.
Facts used to Classify Igneous Rock
1. The crystals in the rock are small or impossible to see with the
unaided eye.
2. The rock has a high amount of silica.
3. The rock appears fine-grained.
4. The rock shows an interlocking texture of crystals.
5. There might be some quartz present in the rock.
6. The rock is darker in color.
7. The escape of gas and rapid cooling leave holes in some rocks.
8. The rock has a low amount of silica.
9. The rock has a rough texture and has holes in it.
10. The rock appears to be coarse-grained.
11, The texture of the rock is smooth like glass.
12. The rock is light in color.
13. The rock is rich in silica.
14. There are no apparent crystals.
15. There are well-defined crystals.
Answer each question in the space provided. Use complete sentences.
Question
What is the
difference
between magma
and lava?
What moves
magma to Earth’s
surface.
Which type of
rock forms when
magma cools
underground?
Where is pumice
present?
Why doesn’t
obsidian have
crystals?
How does basalt
form?
Why is volcanic
ash extrusive
igneous rock?
What effect does
the rate that
magma cools have
on crystal
formation?
Answer
Intrusive Rock
Extrusive Rock