1. Plutonic and Volcanic Activity

2. Intrusive Igneous Bodies

3. What are Plutons?
Concordant plutons 
Laccoliths are _______________________.
Discordant plutons 
Batholiths 
Stocks 
Volcanic pipes 

4. What are characteristics of the 3 Categories of Volcanoes?
What is Volcanism?
What are characteristics of the 3 Categories of Volcanoes?
Active volcanoes 
Dormant volcanoes 
Extinct volcanoes 
Kilauea, Hawaii

5. What are Volcanoes? What is a Crater? What is a Caldera?
Crater Lake, Oregon

6. What is Viscosity? What influences viscosity? Magma Type Silica
Content
Na, K Al
Ca, Fe, Mg
Viscosity
Mafic
Intermed.
Felsic %
> 65
low
medium
high
Increase
Increase

7. Composite Volcanoes (Stratovolcanoes)
Mt. St. Helens, WA

8. Characteristics of Lava Domes
(Mt. Lassen, CA = world’s largest)

9. Characteristics of Shield volcanoes

10. Characteristics of Cinder Cones
SP Crater, Arizona

11. What is
Pahoehoe?

12. What is A'a?

13. What are Lava Tubes & how do they form?

14. What is Pillow lava &
how does it form?

15. Lava solidifies, contracts, & fractures.
What is Columnar jointing?
Oregon

16. What are Pyroclastic sheets?
Marella River valley, Philippines

17. Characteristics of Pyroclastic material
Ash =
Lapilli =
Bombs =
lapilli
bomb
ash

18. Volcanic Gases ________ of gas emitted is water vapor.
Mt. Lassen, Calif.
Volcanic Gases
________ of gas emitted is water vapor.
Lesser amounts of CO2, N, SO2, & H2SO4 are released.
Most gases quickly dissipate.

19. What are Volcanic tremors?
What 4 things must you have to predict eruptions?
What are Volcanic tremors?
What do they indicate?

20. 1. Swelling (magma moves into reservoir)
2. Shape change (increases in slope & distance b/w surface points)
3. Volcanic tremors are produced.
4. Eruption occurs.
5. Volcano deflates & regains its original shape.

21. Where are volcanoes found?

22. Divergent Margins Convergent Margins
Mafic magma forms oceanic crust Intermed. to Felsic magma
Quiescent eruptions Explosive eruptions
Shield volcanoes form along Composite volcanoes & lava Mid-Ocean Ridges domes comprise volcanic arcs

23. What is Intraplate Volcanism?
What type of magma is associated with this type of volcanism?
Where are two locations of intraplate
volcanism?