Tuesday, February 23rd, 1999
Announcements: Second writing assignment due Thursday. Turn in two copies and follow the original guidelines.

Lecture notes:

I. Preview and review
    A. Appalachians (Smokies, Shenandoah)

    B. Compressional vs. collisional (tectonic environment)
            1. Natural consequence of subduction (ocean removal)

    C. Thrust faults
            1. Less than or equal to 200 km transport
            2. Weak link lubricant (shale, limestone, or something with a lot of graphite)
            3. The result is that it thickens the crust (thickest crust is where mountain building is at its peak)
            4. Advection of heat

    D. Rocks
            1. Soils, topography (how resistant to erosion)
            2. Silica (biologically inert)
            3. Decreasing order of fertility
                    a. Limestone (best)
                    b. Basalt
                    c. Granite
                    d. Mud stone (worst)
            4. Particularly good
                    a. Ca (Calcium)
                    b. Mg (Magnesium)
                    c. K (Potassium)
                    d. P (Phosphorus)

II. Rocky Mountains
    A. Formed by compressional tectonism (large scale processes happening as a result of land masses pushing together

    B. Why are the Rocky Mountains not near a continental margin but near the middle of the continent? (Rockies sit
    almost 1000 miles or 1600 km from the coast)
            1. Geologist believe that the Rockies are where they are today because of the break up of Pangea
 
            2. For about 150 million years, masses of rock attached to the edge of the continent therefore destroying the
            continental margin because the land was too weak to deal with 150 million years worth of the impact; the margin
            flowed instead of breaking and eventually shifted to rock that could break

    C. The compressional event that formed the Appalachians is different that the compressional event that formed the
    Rockies

    D. The Rockies are young because limestone is found at the top of its mountains whereas the Appalachians have
    limestone in the valley meaning that the Appalachians have pushed the limestone downwards therefore meaning it
    is an older range of mountains

    E. Rocky Mountains are all about the same height and age  (numerous peaks in Rockies are over 13,000 feet or 4000
    meters)
            1. Very steep, much steeper than Appalachians
 
            2. Because the mountains are steeper, it means the mountains are younger (less erosion to wear the mountains
            down)

    F. Rockies are high mountain climate

    G. Long's Peak (14,256 feet about 4300 meters) dominates the south-central part of the park

III. Miscellaneous
    A. Crystals
            1. In order for crystals to grow they need:
                    a. Time
                    b. Heat
                    c. Nutrient
                    d. This is a diffusion process

            2. "The first things to crystallize are poorer in silica, sodium, potassium, and aluminum, and richer in iron,
            magnesium, and calcium than the melt from which they grew" (Alley 53).
 
    B. Diamonds come from volcanoes

    C. Gold, silver (metals) form where any hot, volcanic area comes in contact with limestone (incredible mineralization)

    D. Metamorphism -- growth of new minerals; advection, revisited
            1. Factors that matter in metamorphism include heat chemically active fluids, pressure and stress

            2. "Most metamorphic rocks have their platy mineral grains aligned in layers, or folia, into which they have been
            flattened by the stress or push" (Alley 51).

    E. How do geologist know if a rock will "fold" or "break"?
            1. Determine the depth of the rock and you therefore you determine the temperature of the rock (the temperature
            allows geologist to determine how close a material is to melting)

            2. Determine the type of the rock
                    a. Weak rocks "fold"
                            ex. limestone, shale

                    b. Strong rocks "break"
                            ex. basalt, sandstone

    F. Deep crustal faults -- granite with great folds came up from far below and traveled along the fault

    G. Steep crustal faults -- (not thoroughly discussed in lecture)

    H. Every time you see limestone you know that this area was under water for a long time where the temperatures are
    warm