Outline of material on Exam II (Friday, October 17):

PART III: ROCKS AND PLATE TECTONICS.

A. Rocks are logical assemblages of minerals.

B. The three rock types.

1. Igneous.
2. Sedimentary.
3. Metamorphic.

C. Rock Types and Plate Tectonic Settings.

D. Processes and Products: The Rock Cycle

E. Igneous rocks.

1. COmposition: understanding the starting material.

• Sources.
• Source control over composition.

2. Cooling rate controls texture.

• Intrusive (plutonic) rocks.
• Extrusive (volcanic) rocks.
• Glass, ash, bombs.

3. Igneous Rock Classifcation.

4. How do magmas form?

• Heat source.
• Geothermal gradients.
• Water in magmas.
• Temperature effect.
• Polymerization of silicates.
  

5. How do magmas and igneous rocks with intermediate compositions form?

• Differentiation.
• Bowen's Reaction Series.
• Magma mixing.

F. Volcanoes.

a. What are they?
b. Lava compositions.
c. Pyroclastic material.
d. Volcano types: Strato-volcano; Shield volcano, Cinder Cone, Caldera volcano.
e.  Importance of volatiles. (H2O, CO2, SO2, F2, Cl2, HCL) Why are they so important?

Part IV. Weathering, Sediments, and Sedimentary Rocks:

A. Sediments and Sedimentary rock categories.

B. Sedimenary Rock Characterisitcs: Interpreting Sediments and Sedimentary Rocks

• grain size,
• sorting, rounding,
• composition relationships).

C. Weathering:

1. Weathering shape the Earth's surface.
2. Weathering of minerals produces soils.
3. Weathering of silicate minerals removes CO2 from atmosphere.
4. Acid rain.
5. Controls on weathering.

   a. Climate.
   b. Relief.
   c. composition of rocks being weathered.

6. Two major categories of weathering:

   a. Mechanical.
   b. Chemical.

   i. Relative stability of minerals.
   ii. Water is critical!
   iii. Chemical weathering processes.
   iv. General reaction for weathering of silicate meinerals.
   v. Clay minerals.

    

7. Weathering Processes and Products.

   a. Soils and weathering.

   • silicate minerals and Carbon dioxide (CO2) in the atmosphere.

   • oxidation of sulfide minerals and acid mine drainage.

   • Why is natural rain slightly acidic?

   • Pollution-caused acid rain.

   • CO2 and limestone.

   b. Products of weathering.

   • Solids (clasts).

   • Ions in solution.

   • New minerals.

   c. What happens to the products of weathering?

   • solids (clasts)
   • Ions.
   • Why are these processes so important for global climate?

    

D. Importance of Sedimentary Rocks (resources).

E. Change sediments to sedimentary rocks: Lithification (cementation).