1. Igneous Rocks and Volcanoes

2. View From Space - Klyuchevskaya, Russia

3. Magma – molten rock beneath the surface Lava – molten rock on the surface

4. Igneous Rocks Cool from the Molten State Volcanic -- Erupted on Surface Plutonic -- Solidify Within Earth Large Grain Size ---> Slow Cooling Volcanic Rocks -- Fine Grained Plutonic Rocks -- Coarse Grained Porphyritic Texture: Large Crystals in Fine-grained Setting

5. Igneous Rock Classification How Much Silica? (account for Si) Excess - Rock Has Quartz Just Enough to Form Other Silicates Deficient - Silica-Poor Minerals (Like Olivine) What Feldspars? (Account for Al, Ca, K, Na ) Potash Feldspar KAlSi 3 O 8 Plagioclase Series NaAlSi 3 O 8......CaAl 2 Si 2 O 8 What Other Minerals Are Present? (Account for Fe, Mg)

6. Feldspars K - Feldspar: KAlSi 3 O 8 Several Slightly Different Forms: Microcline Orthoclase Plagioclase (Solid Solution) Albite: NaAlSi 3 O 8 Anorthite: CaAl 2 Si 2 O 8 Any Mixture of the Two Is Possible

7. Bowen's Reaction Series The geologist N.L. Bowen found that minerals tend to form in specific sequences in igneous rocks These sequences could be assembled into a composite sequence.

8. Bowen's Reaction Series No igneous rock ever displays the whole sequence, just a slice across the sequence.

9. Bowen's Series and Igneous Rocks

10. Volcanic Rocks (Rare) Basalt Andesite Rhyolite Plutonic Rocks Dunite Gabbro Diorite Granite 1200 C Melting Point 700 C Mg, Fe Rich In... Si, Na, K Rapid Weathering Slow Usually Dark Color Often Light

11. Bowen's Series and Volcanoes Volcanic Rocks (Rare) Basalt Andesite Rhyolite Plutonic Rocks Dunite Gabbro Diorite Granite Fluid Lava Is... Viscous Mild Eruptions Violent Type of Volcano Shield Volcano Stratovolcano Plug Dome

12. Some Igneous Rocks Are Named on Textural Criteria Pumice - Porous Obsidian - Glass Tuff - Cemented Ash Breccia - Cemented Fragments Porphyry - Fine Matrix, Large Crystals

13. Types of Volcanoes

14. A Cinder Cone: Wizard Island, Crater Lake, Oregon

15. Anatomy of a Cinder Cone, Hawaii

16. Tuff Ring: Diamond Head, Hawaii

18. Shield Volcano: Haleakala, Hawaii

19. Stratovolcano: Mount Shasta, California

20. Shastina and Landslide Deposit

21. Lava Dome, California

22. Products of Eruptions Lava Flows Pyroclastic Debris Bombs Lapilli Ash Mudflows Landslides Gases Steam Carbon Dioxide H 2 S SO 2 HCl HF

23. Environmental Hazards of Volcanoes Pollution SO2, HCl in Water Lava Flows Falling Ejecta Ash Falls Building Collapse Crop Destruction Mudflows Direct Damage (Colombia, 1985) Floods (Several Types) Blast (Mt. St. Helens, 1980) Pyroclastic Flow (St. Pierre, 1902) Gas (Lake Nyos, Cameroon, 1986)

24. Pyroclastic Flow or Nuee Ardente (French: Fiery Cloud)

25. How Calderas Form

26. Crater Lake, Oregon

27. Jemez Caldera, New Mexico

28. Collapsing Volcanoes – Mount Rainier

29. Collapsing Volcanoes - Hawaii

30. Evolution of Volcanoes An active volcanic landscape

31. Evolution of Volcanoes A volcanic landscape after a million years or so