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Purchase lab manual in lab this week Homework 1 due in lab this week Read Mt. Saint Helens disaster paper

Purchase lab manual in lab this week Homework 1 due in lab this week Read Mt. Saint Helens disaster paper. Igneous Rocks. Earth Materials continued. Mineral - Naturally formed -Solid -Formed by inorganic processes -Specific chemical composition -Characteristic crystal structure.

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Purchase lab manual in lab this week Homework 1 due in lab this week Read Mt. Saint Helens disaster paper

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  1. Purchase lab manual in lab this week Homework 1 due in lab this weekRead Mt. Saint Helens disaster paper

  2. Igneous Rocks

  3. Earth Materials continued Mineral -Naturally formed -Solid -Formed by inorganic processes -Specific chemical composition -Characteristic crystal structure Rock – a coherent, naturally occurring solid, consisting of an aggregate of one or more minerals, or a mass of natural glass or organic matter.

  4. Basic Rock Classifications • Igneous • Sedimentary • Metamorphic

  5. Rock Cycle And Pressure Cementation SedimentaryRocks Erosion/ Weathering Sediment Erosion/ Weathering Heat Erosion Pressure Heat and Pressure Igneous Rocks MetamorphicRocks Cooling Heat Magma

  6. ? Define - Freeze ?

  7. Igneous Rocks -a rock that forms when hot molten rock (magma or lava) cools and freezes solid • Two types of igneous rocks • Plutonic – cools underground • Volcanic – cools above ground

  8. Factors controlling Melting 1. Temperature: Melt at [800oC and 1200oC] Source of heat [radioactive decay]

  9. Geothermal Gradient – the rate at which temperature increases with depth in the Earth 30OC/km

  10. Bowen’s Reaction Series

  11. Iron and Magnesium rich Dark colored minerals Al, Ca, and Sodium rich Light colored minerals

  12. Factors controlling Melting 2. Pressure: • as pressure increases, melting temperature increases • as pressure decreases, melting temperature decreases Lowering pressure causes melting in divergent margins.

  13. Relationship between P, T, and Melt Less Pressure More Pressure

  14. Divergent Plate Boundary

  15. Factors controlling Melting 3. Water content: as water content increases, melting temperature decreases Water in rocks causes melting in convergent margins.

  16. Water increases melting at convergent plate boundaries

  17. Where do igneous rocks occur?

  18. Types of Molten Material 1. Magma – molten material below the Earth's surface 2. Lava – molten material above the Earth's surface

  19. Magma Composition Changes • Partial melting • Assimilation • Magma Mixing • Fractional Crystallization

  20. Partial Melting some minerals melt at a lower temperature than others.

  21. Magma Viscosity Viscosity – resistance to flow honey – high viscosity water – low viscosity Viscosity increases as silica content increases.

  22. Magma Chemistry Molten material can consist of liquid rock, mineral grains and gases (H2O, CO2, SO2). Silicon and oxygen (SiO2) make up the majority of magma 45% SiO2 - "low" silica content 75% SiO2 - "high" silica content

  23. Endmember Magma Chemistry Mafic – low SiO2, iron, magnesium Felsic/Silicic – high SiO2, aluminum, calcium, sodium

  24. Igneous Rock Types Intrusive (plutonic) rock – cools and solidifies below the Earth's surface. Extrusive (volcanic) rock – cools and solidifies above the Earth's surface.

  25. Textures of Igneous Rocks Texture – overall appearance, related to size, shape, and arrangement of minerals. Texture is related to cooling history of an igneous rock, not its chemistry.

  26. Textures of Igneous Rocks 1. Phaneritic (course grained) Magma 2. Aphanitic (fine grained) Lava Glassy Vesicular 3. 4.

  27. Increasing Fe and Mg Increasing silica content

  28. Aphanitic Texture – Rapid Cooling Small Crystals

  29. Phaneritic Texture – Slow Cooling Large Crystals

  30. Silicic Chemical Composition Aphanitic Texture – Rapid Cooling Small Crystals Phaneritic Texture – Slow Cooling Large Crystals Granite Rhyolite

  31. Intermediate Chemical Composition Aphanitic Texture – Rapid Cooling Small Crystals Phaneritic Texture – Slow Cooling Large Crystals Diorite Andesite

  32. Mafic Chemical Composition Aphanitic Texture – Rapid Cooling Small Crystals Phaneritic Texture – Slow Cooling Large Crystals Gabbro Basalt

  33. Phaneritic Porphyritic-Phaneritic Phenocrysts in Groundmass

  34. Aphanitic Porphyritic-Aphanitic Phenocrysts in Groundmass

  35. Pegmatites

  36. Ingersoll Mine Ingersoll mine, Pennington Co., South Dakota, United States One of the many adits at the old Ingersoll pegmatite. Private and Very dangerous. No Trespass.

  37. Glassy Texture - Very Rapid Cooling - No Crystal Structure

  38. Pyroclastic Texture Ash Fall Ash Flow

  39. Plutonic Structures

  40. Plutonic Structures

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