Ch 3. Plate tectonics - Ch 3 Plate Tectonics A Unifying...

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Unformatted text preview: Ch. 3: Plate Tectonics A Unifying Theory Key Words- Continental Drift- Paleomagnetism- Polar Wandering- Magnetic Reversals- Seafloor Spreading- Plate Boundaries o Divergent o Convergent o Transform- Hot spots ______________________________________________________________________ __ Continental Drift Hypothesis- A. Wegener : The Origin of Continents and Oceans (1915) o Pangaea (all land) o Evidence: fossils Fit of the Continents Identical rock sequences Mountain ranges Glacial deposits - E. Suess: o Gondwanaland ( Gondwana ) o Glossopteris flora (Late Paleozoic; India, Australia, S-Africa, S-America, Antacrctica)- A. du Toit: Our Wandering Continents (1937) o Glacial deposits (S) vs. coal deposits (N) Climatologic paradox o Laurasia (N-continent: N-America, Greenland, Europe, Asia (except India)) o Mesosaurus (freshwater reptile; Brazil and S-Africa)- Mid-Atlantic Ridge (discovered 1870s HMS Challenger ; F. Taylor) Driving Mechanism?? Paleomagnetism- Remanent magnetism in ancient rocks 1 o Fe-bearing minerals o Curie point - Record of direction and intensity of Earths magnetic field at the time of a rocks formation- Earths magnetic field result of different rotation speeds of the outer core and mantle Polar Wandering Apparent change in the location of the poles through time Magnetic Reversals- Normal (e.g. today) or reversed magnetic field- Mapping of ocean basins (1960s) Seafloor Spreading Theory- H. Hess (1962)- Seafloor separates at oceanic ridges, new crust is formed by upwelling magma, new crust moves laterally away from ridge- Thermal convection cells in mantle- Supporting evidence o Magnetic anomalies (deviations from the average strength of Earths...
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This note was uploaded on 03/27/2012 for the course GEOL 2413 taught by Professor Moody during the Spring '10 term at Texas A&M University, Corpus Christi.

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Ch 3. Plate tectonics - Ch 3 Plate Tectonics A Unifying...

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