EESA06H3 Lecture Notes - Supercontinent Cycle, Oa, Echo Sounding
25 Jan 2012
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Document Summary
Formation of planet earth: 4500 million years before present. Magnetic stripes on the ocean floor and wander paths for continents 1965 fred. Mid-ocean ridges and hot spots: 1965 tuzo wilson. Plate tectonics and wilson cycle: 1967 tuzo wilson. Wegener proposed that continents moved by plowing through the sea floor. Pangea consists= laurasia (n america & asia)+gondwana (southern continents, Continent fits!! north america, south america; europe and africa. Make sense when you put all the continents together. Harold hess introduced idea of sea floor spreading (1962) Sea floor created mor"s recycled into mantle at trenches. Magnetometer surveys of ocean floor identified patterns of anomalies on each side of mor"s. Magnetometer -measure the direction and strength of the magnetic plans. Paleomagnetism and magnetic stripes on the ocean floor. The earth"s magnetic field: our protective shield. Solid core, liquid outer core, core rotate slightly faster than mantle. Magnetic alignment preserved in magnetite records orientation of earth"s field.
