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Unformatted text preview: Lecture #1 14/02/2007 10:38:00 geologic cycle Materials <= Emphasize interaction Processes Materials solid earth o Minerals- basic building blocks of the earth letters, put together to form rocks(words) o Rocks- Igneous, Sedimentary, Metamorphic words, things put together in certain ways, used to read the earths history Processes Internal- beneath the earths surface, we cant see how they occur but we can see their effects and then test the conditions to produce the same result. i.e. earthquakes, mountain building, volcanism. All these have surface manifestation that we see even though the process is internal to the earth. Driven by some sort of energy, in this case it is heat energy. The source of the energy is two-fold: Remnant heat=> from the earths original cooling. Radioactive Decay=> i.e. Uranium, below the crust, causing heat External- directly shape the earth: o Weathering- breakdown of the rock material at the earth surface, temperature and the rainfall work together to govern this process o Mass Wasting- a mass of material moved solely by gravity, aided by water and wind but they do not do the actual transportation. Mass wasting can occur at any downslope o Erosion- differs from Mass wasting because there is an agent of transport involved in the process Running water (sheet flow or river channels) Waves & Currents Wind Groundwater Glaciation o Deposition- material removed from some sources, and moved into lower areas. o Heat Energy- A solar source drives the external process, the atmosphere is heated up, the less dense air rises, cooler air sinks that create wind the therefore weather. Which then affect the transportation methods that cause Mass Wasting, Erosion, Weathering, and Deposition. What is the net affect of all these methods of transportation???? All continents could be reduced/erode to sea level. Theoretically if the transportation methods are used the surface will become lever Time affects the speed of the weathering that some rocks experience. The plates of the world will occasionally uplift and counter-act the external processes need to bring the surface level down. The internal forces cause this counteraction. So for the most part they balance out. But in some areas i.e. the Himalayans, and grand canyon area, the internal processes are overpowering the external forces. The interaction between the internal and external processes are those that cause the earth to be a Dynamic Planet, the interactions combined with time...
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- Fall '05