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2011-10-10 19:11:57

geo topics for exam
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  1. 5 criteria to be classified as minerals
    - Naturally occurring

    - Solid substance

    - Orderly crystalline structure

    - Generally Inorganic

    -Well defined chemical composition
  2. Physical properties

    - Ability to transmit light


    - Streak

    - Tenacity


    - Cleavage
  3. Silicates
    - they all contain oxygen and silicon atoms.

    --carry silicon-oxygen tetrahedron

    -some form from molten rock as it cools, others formed at earths surfaces as weather erodes.
  4. non-silicates
    - only make 8 percent of earths crust.

  5. magma
    -is melting that occurs primarily within earth's crust and upper mantle
  6. Lava
    - its magma tha reaches earth's surface.
  7. (Igneous) Felsic- Granitic
    Quartz, potassium feldspar

    - Coarsed grained: granite

    - Fine grained: Rhyolite

    - Glassy: Obsidian and Pumice
  8. (igneous) Intermediate- Andesitic
    Amphibole, sodium and calcium rich

    - Coarsed grained: Diorite

    - Fine-grained: Andesite

    - Glassy: Obsidian and Pumice
  9. (igneous) Mafic- Basaltic
    Pyroxene, Calcium-rich

    - Coarse-grained: Gabbro

    - Fine grained: Basalt

    - Glassy- Obsidian
  10. (igneous) Ultramafic
    Olivine and pyroxene

    - Coarse-grained: Peridotite

    - Fine grained: Komatiite
  11. Chemical weathering
    - water is the most important agent of chemical weathering

    - Carbon dioxide is another chemical weathering.
  12. Mechanical weathering
    this process breaks down small pieces of the object but retains its properties.

    - Frost wedging


    - Biological activity
  13. Detrital sedimentary rocks
    - they form from solid products of weathering
  14. Chemical sedimentary rocks
    - derived from solutions that are carried to the lakes and seas.
  15. Lithification
    refers to processes by which sediments are transformed into solid sedimentary rocks.

    Compaction: most common process, overlying material compresses the deeper sediments.

    Cementation: the cementing materials are carried in solution by water percolating through its pores.
  16. Sedimentary rock features
    - some may contain fossils

    - Strata and beds are the most common trait
  17. (metamorphic triggers) Heat
    - It results in recrystallization of existing minerals and formation of new mineral.

    - Rocks can increase their tempertaure by having magma touching them, calling them baked rock.
  18. (metamorphic triggers) Pressure
    - temperature increases the further one goes down as pressure as well.

    - confining pressure causes the spaces between minerals grains to close.
  19. (metamorphic triggers) Chemical
    - they aid in recrystallization
  20. Common foliated texture
    Slate, schist, and gneiss
  21. common non-foliated texture
    Marble and quartzite
  22. Divergent boundaries
    is a boundary where 2 plates are moving away from one another
  23. Convergent boundary
    two plates in which they come together
  24. Transform fault boundary
    two plates rub against one another in a sideways motion
  25. calculate rate of plate motion
    cm/ year