5.1 Igneous Rocks

2,477 views
2,302 views

Published on

0 Comments
5 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
2,477
On SlideShare
0
From Embeds
0
Number of Embeds
36
Actions
Shares
0
Downloads
209
Comments
0
Likes
5
Embeds 0
No embeds

No notes for slide
  • 5.1 Igneous Rocks

    1. 1. Igneous Rocks Pages 99 - 113
    2. 2. Goal 1 Compare and contrast intrusive and extrusive igneous rocks
    3. 3. All rocks are a mixture of minerals. Mineral soup
    4. 4. <ul><li>Each type of rock has its own mix of minerals </li></ul>Gabbro: minerals include hornblende, plagioclase, pyroxene, biotite, olivine, magnetite
    5. 5. <ul><li>Extrusive Igneous Rocks </li></ul>
    6. 6. <ul><li>1. Lava cooled quickly at surface </li></ul>
    7. 8. Kalapana, Hawaii 1990
    8. 9. Lava fountain height approx 10 m Pu‘u Kahaualea , photo by J.D. Griggs, 02/25/83 USGS
    9. 10. <ul><li>2. Fine grain / glassy </li></ul>
    10. 11. <ul><li>3. Examples </li></ul>Obsidian Pumice
    11. 12. <ul><li>Intrusive Igneous </li></ul><ul><li>Rocks </li></ul>
    12. 13. <ul><li>1. Cooled magma inside Earth </li></ul>
    13. 14. <ul><li>2. Cross cutting relationships </li></ul>Photo credit: Eurico Zimbres
    14. 15. Photo credit: Wing-chi Poon at Devil's Lookout Point, Black Canyon Gunnison National Park, Colorado, USA
    15. 16. <ul><li>3. Coarse Grain </li></ul><ul><li>+large, interlocking crystals </li></ul><ul><li>+naked eye </li></ul>
    16. 17. <ul><li>4. Examples </li></ul>
    17. 18. Granite porphyry: coarse grains surrounded by fine grains
    18. 19. Goal 3 Explain the 4 factors that affect how rocks melt and crystallize
    19. 20. <ul><li>Magma forms in the Earth’s Mantle </li></ul><ul><li>Slushy mix </li></ul><ul><li>Solids </li></ul><ul><li>Liquids </li></ul><ul><li>Gases </li></ul>
    20. 21. <ul><li>Temperature </li></ul><ul><ul><li>Temp increases w/ depth </li></ul></ul>
    21. 22. <ul><li>2. Pressure </li></ul><ul><li>a) pressure increases with depth </li></ul><ul><li>b) increased pressure = higher melting temp </li></ul>
    22. 23. <ul><li>3. Water content </li></ul><ul><li>a) water increase = melting point decrease </li></ul>
    23. 24. <ul><li>4. Mineral composition </li></ul><ul><li>a) minerals have individual unique melting points </li></ul>
    24. 25. <ul><li>Bowen’s Reaction series </li></ul><ul><li>Explains the order in which minerals crystallize out of a magma solution </li></ul>
    25. 26. <ul><li>Bowen’s Reaction Series </li></ul>Image Credit: James Madison University Geology Dept.
    26. 27. <ul><li>Left side </li></ul><ul><li>Iron-rich minerals </li></ul><ul><li>Discontinous </li></ul><ul><li>crystallization </li></ul>Right side Feldspar minerals Continuous crystallization
    27. 28. SiO 2 content is related to classification Dark / Green Ultramafic 0% Dark Mafic < 50% Basaltic ½ light ½ dark Intermediate ~ 60% Andesitic Light Felsic > 70% Rhyolitic General color Classification SiO 2 content Magma type
    28. 29. <ul><li>Summary </li></ul><ul><li>Texture related to location of crystallization </li></ul><ul><ul><li>Fine grain = extrusive </li></ul></ul><ul><ul><li>Coarse grain = intrusive </li></ul></ul><ul><ul><li>Porphyritic = intrusive </li></ul></ul>
    29. 30. <ul><li>Mineral content related to crystallization series </li></ul><ul><ul><li>Fe rich = discontinuous </li></ul></ul><ul><ul><li>Na, Ca Feldspars = continuous </li></ul></ul>
    30. 31. <ul><li>Classification related to SiO 2 content and color </li></ul><ul><ul><li>Light = Felsic </li></ul></ul><ul><ul><li>½ and ½ = Intermediate </li></ul></ul><ul><ul><li>Dark = Mafic </li></ul></ul><ul><ul><li>Very dark / green = Ultramafic </li></ul></ul>
    31. 32. Determining if a rock is Igneous: <ul><li>Hard, scratches glass </li></ul><ul><li>No banding or layers of colors </li></ul><ul><li>Coarse-grain (large crystals) that interlock </li></ul><ul><li>Fine-grain (small crystals), glassy, light / holey from gas pockets </li></ul><ul><li>Common colors: black, white, gray, reds to pinks </li></ul>
    32. 33. <ul><li>Thanks to the following people who have generously shared photos on the creative commons at Flickr: </li></ul><ul><li>The Shifted Librarian… Road Closed </li></ul><ul><li>James_C… Red granite Cross </li></ul><ul><li>Kevinzim… gabbro slice </li></ul><ul><li>Jeff gerhard… lava </li></ul><ul><li>AZAdam… lava tube </li></ul><ul><li>Travis S… obsidian point </li></ul><ul><li>Ambuj Saxena… pumice </li></ul><ul><li>Kevinzim… coarse grain intrusive </li></ul><ul><li>Basial… Intrusive examples </li></ul>

    ×