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17 Cards in this Set
- Front
- Back
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5 Geomorphology perspectives
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1. Earth-Science Perspective
2. Ocean-Science Perspective 3. Theoretical Perspective 4. Engineering Perspective 5. Remote Sensing Perspective |
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Earth Science Perspective
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Catastrophism vs uniformitarianism (18-19th cent). 19th cent most surveys & research. Early notions of RSL (1. continents shaped by marine denudation, 2. land subject only to marginal submergance)
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Ocean-Science Perspective
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Royal Societies 1666 improved instrumentation. First bathymetrical charts of Atlantic 1855. HMS challenger first oceanographic expedition. Now physical probing and remote sensing of ocean depths.
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Theoretical Perspective (Mathematicians)
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Scientific revolution, classical wave theory (trochoidal vs. sinusoidal). Shallow water wave theory 1900's, Scripps research WWII.
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Engineering Perspective
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Early use for flood protection, wetland reclamation. Coastal erosion natural, engineering can't solve problem. Nourished beaches (bring sand from somewhere else).
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Remote Sensing Perspective
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Early from balloons, aerial photography in 1920s, satellites after 1960's, big business today.
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Questions of Scale
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Rates of change related to size-small respond quickly, large slowly (1000s-millions yrs).
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Relative Sea Level Change (RSL)
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Coast reflects level of sea relative to land. Changes b/c of 1. absolute changes in oceal volume (glaciation)
2. Absolute changes in Earth's crustal behavior. (high freeboard) |
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Major tectonic plates
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Africa, Pacific, So. American, No. American, Eurasian, Antarctic
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Minor tectonic plates
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Australian, Nazca, Caribbean, Scotia, Arabian, Arabian, Filipino, Cocos, Juan de Fuca
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Wilson cycles
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supercontinents assemble every 500 Ma and then break up. Last one Pangea 300-200 Ma- broke up into Laurussia and Godwana.
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Mechanisms of plate motions
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Plates mobile, movement start with fissures in earths crust. Sea floor spreading= continents ripped away.
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Passive Coasts
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Structure at right angle to coast (discordant). Atlantic coasts.
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Active Coasts
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Structures parallel to coast (concordant). Pacific coasts. Plates colliding.
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Passive margin coasts and expanding oceans
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1. Embryonic- modern rifting of East Africa, late Triassic rifting of Atlantic.
2. Incipient- modern Red Sea, Gulf of CA, late Jurassic Tethys 3. Narrow Ocean- Jurassic No. Atlantic, Cretaceous So. Atlantic & Tethys 4. Developed- Modern Atl., still widening 3-4cm/yr |
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Active Margin Coasts and contracting oceans
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1. Contracting Ocean: plate convergence a ' nd subduction leading to trenches (peru-chile, Andes, mesoamerica, marianas, aleutians)
2. Terminal Ocean: Shrinkage to a large sea w/ bordering uplift or subduction (shrinking of tethys to form modern Med-Black-Caspian Sea) 3. Relict Scar- Oceans squeezed out by cont-to-cont collision (Indian suture w/ Asia) 4. Lateral shear- where plates move laterally alongside one another (Baja CA to mainland Mexico) |
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Glacio-isostacy
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Scandanavia, scotland, hudson bay
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