Earth Sciences 2240F/G Lecture Notes - Lecture 5: Outer Core, Basalt, Convergent Boundary
17 Sep 2020
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This is what makes earth diff from others connected with other similar ridges far south. Alfred wegner: jigsaw of continents, terrain of continents fitted together, continuity of fossils. Wwii: submarines found repetitive magnetic records in ocean floor. After war: in atlantic ocean, found huge volcanic ridge that extended right from north and. Harry hess: ridges as spreading centers where earth"s crust was moving in opposite. Paleomagnetism & earths mf directions, allow new ocean floor to be built from volcanic rock at the ridges: earth has strong mf that defines north/south poles. Do to the dynamo model: driven by circulating hot currents of liquid outer core and. Not always stable, when liquid pattern changes the orientation flips: basalt when cools magnetite (iron oxide) which orient themselves in direction of. Wwii: submerged magnetometers found parallel strips of ocean floor (basalt) that had alternating mf orientation. Earthquakes: produced by movement along fractures in crust.
